Engine Performance System Self-Diagnostics Acura MDX I

INTRODUCTION

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES article, proceed with self-diagnostics. If no fault codes, or only pass codes exist after entering self-diagnostics, proceed to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.).

SELF-DIAGNOSTIC SYSTEM

1. With ignition on, connect the Honda PGM Tester or the HDS to the data link connector (DLC) and go into any of the live data screens.
2. Turn ignition off.
3. Turn the Honda PGM Tester off or close the HDS and then back on. Go to the SCS mode and follow the screens to ground the 16-pin DLC.

MIL Stays Illuminated

1. Start engine and check MIL.
2. If MIL stays illuminated, turn ignition switch off. Connect scan tool to DLC. (Scheme 1)
3. Turn ignition switch on. Record DTCs and freeze data listed on scan tool. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__diagnostic-trouble-code-definitions). Perform appropriate trouble shooting procedure. NOTE: Freeze data indicates engine conditions when the first malfunction, misfire or fuel trim malfunction occurred.
4. If no DTCs are found, go to «TROUBLESHOOTING MALFUNCTION INDICATOR LIGHT»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__troubleshooting-malfunction-indicator-light).

MIL Not Illuminated

If MIL does not stay illuminated but driveability problem exists, refer to SYMPTOM DIAGNOSIS under SYMPTOMS in TROUBLE SHOOTING - NO CODES article.

DTC Cannot Be Duplicated

Some DTC trouble shooting requires you to reset PCM and try to duplicate DTC. If problem is intermittent and DTC cannot be duplicated, do not continue trouble shooting procedure. Continuing with procedure will only result in confusion and possibly, needless replacement of PCM.

MALFUNCTION INDICATOR LIGHT

As a bulb check, Malfunction Indicator Light (MIL) illuminates for 15 to 20 seconds when ignition is on and engine is not running. MIL also illuminates when a system failure has been detected and a corresponding DTC has been set in PCM memory. Not all trouble codes will activate MIL. If MIL comes on and no DTCs are stored in memory, problem may be caused by an intermittent electrical problem and not necessarily a faulty component. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.

Hard Failures

Hard failures cause MIL to illuminate and remain on until problem is repaired. If light comes on and remains on (light may flash) during vehicle operation, cause of malfunction must be determined by retrieving Diagnostic Trouble Codes (DTCs). See RETRIEVING DIAGNOSTIC TROUBLE CODES . If a sensor fails, control unit will use a substitute value in its calculations to continue engine operation. In this condition, commonly known as limp-in mode, the vehicle will run, but driveability will not be optimum.

Intermittent Failures

Intermittent failures may cause MIL to flicker or illuminate and go out after the intermittent fault goes away. The corresponding DTC will be retained in PCM memory. If related fault does not reoccur within 50 ignition cycles, related DTC will be erased from PCM memory. Intermittent failures may be caused by sensor, connector or wiring related problems. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.

RETRIEVING DIAGNOSTIC TROUBLE CODES

Note. For complete self-diagnostic capabilities a Honda PGM Tester or HDS is required.

Using Scan Tool

Locate Data Link Connector (DLC). (Scheme 1) Connect and operate scan tool in accordance with manufacturer's instructions.

Scheme 1

FREEZE DATA

Freeze data indicates engine operating conditions when the first malfunction, misfire or fuel trim malfunction was detected. Freeze data can be helpful when used during trouble shooting. A scan tool must be used to check for freeze data.

PCM RESET PROCEDURE/CLEARING DIAGNOSTIC TROUBLE CODES

To clear codes use the Honda PGM Tester or the HDS use the "CLEAR COMMAND". The PCM stores data and DTCs to correct the system even when there is no electrical power such as the NO. 10 BACK UP fuse or battery negative cable disconnected.

Honda PGM Tester and HDS has 3 kinds of clear commands to meet the purpose.

1. DTC clear. This command erases all stored DTC codes and Freeze Data.
2. PCM clear. This command erases all stored DTC codes, Freeze Data and all specific data to correct the system except CKP pattern.
3. CKP clear. This command erases only CKP pattern data. This command is for the repair of a misfire or CKP sensor. If CKP pattern data is cleared from PCM, you must do the CKP pattern relearn procedure by test drive. See «CKP PATTERN LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__ckp-pattern-learn-procedure) .

PCM REMOVAL & REPLACEMENT

Note. The PCM in 2003 has a self-shutdown feature that writes data to memory and does diagnostic functions for up to 18 hours after you turn the ignition switch to LOCK. To keep from permanently damaging the PCM or losing data, do this procedure before unplugging the PCM: With ignition switch in ON position, connect PGM tester to DLC. Power on tester. Select CURRENT DATA to establish communication between PGM tester and PCM. Communication must be established between tester and PCM before turning ignition switch to LOCK position. Turn ignition switch to LOCK position. Exit to MENU. Select SCS, and follow the screen prompts to ground the 16-pin DLC. DO NOT press EXIT key or you will drop out of SCS mode. Once DLC is properly grounded, you can safely unplug the PCM. Using this procedure to short the SCS stops the data writing process that normally occurs right after the ignition is turned to LOCK position. If you short the SCS before turning the ignition switch to LOCK, the ECM/PCM goes into 1-trip mode, which does not stop the data writing process nor prevent ECM/PCM damage. If you disconnect the negative battery cable before unplugging the ECM/PCM, damage will not occur but ECM/PCM will lose CKP pattern and idle learn data. For CKP pattern learn procedure, see CKP PATTERN LEARN PROCEDURE . For idle learn procedure, see PCM IDLE LEARN PROCEDURE .

PCM IDLE LEARN PROCEDURE

Note. Using the Honda PGM Tester or the HDS to "clear" DTCs does not require this procedure.

Note. This procedure must be done so the PCM can learn the engine idle characteristics. Do the procedure when: PCM is replaced. PCM is reset. Throttle body is replaced.

Idle Learn Procedure

1. Make sure all electrical accessories are off.
2. Connect the Honda PGM Tester or the HDS and perform PCM RESET in the CLEAR menu.
3. Turn ignition switch on and wait 2 seconds.
4. Start engine and hold at 3000 RPM with no load (A/T in N or P position) until radiator fan comes on, or until engine coolant temperature reaches 194°F (90°C).
5. Allow engine to idle for about 5 minutes with throttle fully closed. NOTE: If radiator fan comes on, do not include its running time in the 5 minutes.

CKP PATTERN LEARN PROCEDURE

Note. Enable criteria: Engine coolant temperature must be 176°F (80°C) or higher.

1. Having cleared the CKP pattern from PCM, leave Honda PGM Tester or the HDS connected to DLC and turn ignition switch off. Turn ignition switch on. Wait for 30 seconds.
2. Start vehicle and test drive on a level road. Decelerate (with throttle fully closed) from engine speed of 2500 RPM to 1000 RPM with A/T in "2" or "D3" position.
3. Stop vehicle. DO NOT turn the ignition switch off. Select the ALL DATA list in DATA LIST menu using Honda PGM Tester or the HDS .
4. Check status of PULSER F/B LEARN. If it is set to NG, enable criteria was probably not met; repeat the procedure from beginning.

PCM LOCATION

PCM is located in the right side of engine compartment towards the front of vehicle. Connect test equipment using backprobe set. See TEST EQUIPMENT . Check system according to procedures described in specific Diagnostic Trouble Code (DTC) tests.

TEST EQUIPMENT

All voltage tests should be performed by backprobing using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless specifically stated differently in testing procedure. DO NOT use a test light or analog meter to check circuits with solid-state devices. Solid-state devices can be damaged. Ensure all jumper wire(s) include a (5-amp) in-line fuse.

Use 2 Backprobe Sets (07SAZ-001000A) to backprobe Powertrain Control Module (PCM) terminals when directed by testing. (Scheme 2)

DO NOT puncture wire insulation. Place tester probe into contact with terminal from terminal side of wiring harness connector(s) in engine compartment. For female connector(s), touch terminal lightly with tester probe. DO NOT insert probe into terminal.

Note. For PCM harness connector terminal identification, see CONNECTOR IDENTIFICATION .

Note. Circuit tests are written specifically for use with Honda PGM Tester. Other scan tools can be used but may have limited functions.

Scheme 2

SYSTEM READINESS TEST CODES

If battery has been disconnected, DTCs have been cleared or PCM has been reset, readiness codes will reset. In some states part of emission testing is to ensure readiness codes are complete. If readiness codes are not complete, emission test cannot be finished.

To check if readiness codes are complete, turn ignition switch on, engine off. MIL will illuminate for 15-20 seconds. If MIL goes off, readiness codes are complete. If MIL blinks 5 times, one or more readiness codes are not complete.

To set each code, drive vehicle or run engine as described in following procedures.

Catalytic Converter Monitor & Readiness Code

Note. Do not turn ignition switch off.

Note. Enable criteria includes: Ensure ambient temperature is 20-95°F (-7-35°C). Engine coolant temperature at 158°F (70°C) or higher. Intake air temperature at 20°F (-7°C) or higher. Vehicle speed sensor reads more than 25 MPH.

1. Connect Honda PGM Tester or the HDS to DLC. (Scheme 1)
2. Start engine and test drive vehicle under stop-and-go conditions with short periods of steady cruise. After about 5 miles readiness code should switch to passed.
3. Using Honda PGM Tester or the HDS, check for readiness code. If readiness code is not set to complete, repeat the procedure.

EGR Monitor & Readiness Code

Note. Do not turn ignition switch off during this procedure.

Note. Enable criteria includes: Engine coolant temperature at 176°F (80°C) or higher.

1. Connect Honda PGM Tester or the HDS to DLC. (Scheme 1)
2. Start engine and test drive vehicle at a steady speed with A/T in "D" position 50-62 MPH or above for more than 10 seconds.
3. Decelerate from 50-62 MPH or above by completely releasing throttle for at least 5 seconds.If the engine stops during procedure, start test drive again.
4. Using Honda PGM Tester or the HDS, check OBD status screen for DTC P0401 in the DTCs menu. If it passed readiness is complete. If readiness is not set to complete, repeat the procedure.

EVAP Emission Control System Monitor & Readiness Code

Note. Enable criteria includes: Battery voltage is 8 volts or higher. A/T in "N" or "P" position. Engine stopped.

1. Connect Honda PGM Tester or the HDS to DLC. (Scheme 1)
2. Start engine. Select EVAP test in INSPECTION menu. Then select FUNCTION TEST.
3. Check OBD status screen for EVAP DTCs P0442, P0456 and P0457 in the DTCs menu.
4. If they are passed, the readiness code is set. If they are not passed, go to next step.
5. If readiness code is not complete, check for a temporary DTC. If there is no DTC, one or more of enable criteria was not met; repeat procedure.

Air Fuel Ratio (A/F) Sensor Monitor & Readiness Code

Note. Do not turn ignition switch off.

Note. Enable criteria includes: Ensure engine coolant temperature is 140°F (60°C) or higher.

1. Connect Honda PGM Tester or the HDS to DLC. (Scheme 1)
2. Start engine.
3. Start engine and test drive vehicle under stop-and-go conditions with short periods of steady cruise. During test drive decelerate by completely releasing throttle for at least 5 seconds. After about 3.5 miles, the readiness code should switch from not complete to complete.
4. Check the OBD status screen for Air Fuel Ratio (A/F) DTCs P0133 or P2A00 in the DTCs menu. If they are passed, readiness code is set. If they are not passed, go to next step.
5. If readiness code is not complete, check for a temporary DTC. If there is no DTC, one or more of enable criteria was not met; repeat procedure.

Air Fuel Ratio (A/F) Sensor Heater Monitor & Readiness Code

1. Connect Honda PGM Tester or the HDS to DLC. (Scheme 1)
2. Start engine and let idle for 1 minute. The readiness code should switch from not complete to complete.
3. If readiness code is not complete, check for a temporary DTC. If there is no DTC, one or more of enable criteria was not met; repeat procedure.

Misfire Monitor & Readiness Code

1. This code is always set to available because misfiring is continuously monitored.
2. Monitoring pauses and the misfire counter resets, if the vehicle is driven over a rough road.
3. Monitoring pauses and the misfire counter holds its current value, if throttle position changes more than a predetermined value, or if driving conditions fall outside the range of any related enable criteria.

Fuel System Monitor & Readiness Code

1. This code is always set to available because fuel system is continuously monitored during closed loop operation.
2. Monitoring pauses when catalytic converter, EVAP control system and A/F sensor monitors are active.
3. Monitoring pauses when any related enable criteria are not being met. Monitoring resumes when enable criteria are again being met.

Comprehensive Component Monitor & Readiness Code

This code is always set to available because comprehensive component monitor is continuously running whenever the engine is cranking or running.

SUMMARY

If no hard fault codes (or only pass codes) exist, driveability symptoms exist, or intermittent codes exist, proceed to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION

CONNECTOR IDENTIFICATION

Note. PCM is located in right side of engine compartment towards the front of vehicle. For connector identification, refer to illustrations. (Scheme 3)or (Scheme 4).

Scheme 3

Scheme 4

DIAGNOSTIC CIRCUIT CHECK

Note. To identify PCM connectors, see illustration. (Scheme 4)

TROUBLESHOOTING MALFUNCTION INDICATOR LIGHT

1. Turn ignition switch on and observe Malfunction Indicator Light (MIL). If MIL always comes on and stays on, go to step 11. If MIL stays on but sometimes works normally, check for following: Intermittent short in Brown wire between PCM harness connector terminal B54 and DLC 16-pin connector terminal No. 9. (Scheme 3)or (Scheme 4). Intermittent short in Green/Orange wire between PCM harness connector terminal B5 and gauge assembly harness connector "A" terminal A30. (Scheme 21) Repair wiring as necessary. If MIL stays off, go to next step. If MIL stays off but sometimes works normally, check for following malfunctions: Loose No. 9 BACK UP LIGHT, INSTRUMENT LIGHT fuse (10-amp) in driver's under-dash fuse/relay box. Loose No. 46 ACG S fuse (15-amp) in under-hood fuse/relay box. Loose No. 1 FUEL PUMP fuse (15-amp) in driver's under-dash fuse/relay box. Intermittent connection between PCM harness connector terminal B5 (Green/Orange wire) and the gauge assembly harness connector "A" terminal A30. Intermittent open in Green/Orange wire between PCM harness connector terminal B5 and gauge assembly harness connector "A" terminal A30. Intermittent short in Yellow/Red wire between PCM harness connector terminal A7, MAP sensor and counter shaft speed sensor. Intermittent short in Yellow/Blue wire between PCM harness connector terminal A27, EGR valve position sensor, main shaft speed sensor, or intake manifold runner control actuator. Intermittent short in Yellow/Black wire between PCM harness connector terminal B43 and the (APP) sensor. Intermittent short in Yellow/White wire between PCM harness connector terminal B29 and the accelerator pedal position (APP) sensor. Intermittent short in Yellow/Blue wire between PCM harness connector terminal B46 and the fuel tank pressure (FTP) sensor. For connector views, see «CONNECTOR IDENTIFICATION»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__connector-identification). See appropriate wiring diagram under ENGINE PERFORMANCE in WIRING DIAGRAMS. Repair as necessary.
2. Turn ignition switch off, then on. If low oil pressure light is on, go to next step. If low oil pressure light is not on, check for a blown No. 9 BACK UP LIGHT, INSTRUMENT LIGHT fuse (10-amp) in driver's under-dash fuse/relay box. Also check for short or open in wire between No. 9 BACK UP LIGHT, INSTRUMENT LIGHT fuse (10-amp) in driver's under-dash fuse/relay box and gauge assembly.
3. Attempt to start engine. If engine starts, go to next step. If engine does not start, go to step 5.
4. Turn ignition switch off. Disconnect PCM "B" harness connector. Connect fused jumper wire between ground and PCM harness connector terminal B5. Turn ignition switch on. If MIL comes on, substitute known-good PCM, then recheck. If symptom or indication goes away, replace original PCM. If MIL does not come on, check for blown MIL bulb or open in Green/Orange wire between PCM harness connector terminal B5 and gauge assembly harness connector "A" terminal A30.
5. Turn ignition switch off. Inspect No. 46 ACG S fuse (15-amp) in under-hood fuse/relay box. If fuse is OK, go to next step. If fuse is not good, check for a short in wire between No. 46 ACG S fuse (15-amp) in under-hood fuse/relay box and PGM-FI main relay. Check for a short in wire between PGM-FI main relay and the PCM, injectors, CKP sensors or CMP sensor.
6. Inspect No. 1 FUEL PUMP fuse (15-amp) in driver's under-dash fuse/relay box. If fuse is OK, go to next step. If fuse is not good, check for a short in wire between No. 1 FUEL PUMP fuse (15-amp) in driver's under-dash fuse/relay box PGM-FI main relay. Check for a short in wire between PGM-FI main relay and the fuel pump. Check for faulty PGM-FI main relay or a faulty fuel pump.
7. Disconnect PCM "A" harness connector. With both PCM harness connectors disconnected, measure continuity between ground and terminals A7, A27, B29, B43 and B46 individually. If there is continuity, go to next step. If there is no continuity, go to step 9.
8. Disconnect the connector from each of these sensors, one at a time while checking for continuity between ground and terminals A7, A27, B29, B43 and B46 individually. (A7) (Yellow/Red wire) Countershaft speed sensor (A27) (Yellow/Blue wire) EGR valve position sensor (B46) (Yellow/Blue wire) Fuel Tank Pressure (FTP) sensor (A27) (Yellow/Blue wire) Mainshaft speed sensor (A7) (Yellow/Red wire) Manifold Absolute Pressure (MAP) sensor (B29) (Yellow/White wire) APP sensor If there is continuity, repair short to ground in wire between PCM and the sensor with the problem wire. If there is no continuity, replace the sensor that made continuity to ground go away when disconnected.
9. Disconnect the injectors, CKP sensors and CMP sensor connectors, Turn ignition switch on. Measure voltage between ground and PCM harness connector terminal A18. If there is battery voltage, go to next step. If there is not battery voltage, check for an open in wire between PGM-FI main relay and PCM connector terminal A18. Check for poor connection at PGM-FI main relay. Check for faulty PGM-FI main relay. See appropriate wiring diagram under ENGINE PERFORMANCE in WIRING DIAGRAMS. If necessary repair or replace the part.
10. Check for continuity between ground and PCM harness connector terminals A39, A30 and A73. If there is continuity, substitute known-good PCM, then recheck. If symptom or indication goes away, replace original PCM. If there is not continuity, repair open in wires between ground (G101) and PCM harness connector terminals A39, A30 and A73.
11. Turn ignition off. Reconnect PCM harness connectors. Turn ignition on. Measure voltage between ground and DLC connector terminal No.9 (Brown wire). If there is about 5 volts, go to step 13. If there is not about 5 volts, go to next step.
12. Turn ignition off. Disconnect PCM harness connector "B". Check for continuity between ground and PCM connector terminal B54. If there is continuity, repair short in wire between PCM harness connector terminal B54. If there is not continuity, substitute known-good PCM, then recheck. If symptom or indication goes away, replace original PCM.
13. Turn ignition off. Disconnect PCM harness connector "A". Turn ignition on. If the MIL stays on, repair short in green/orange wire between gauge assembly harness connector "A" terminal A30 and PCM harness connector terminal B5. If the MIL does not stay on, substitute known-good PCM, then recheck. If symptom or indication goes away, replace original PCM.

DTC P0097: INTAKE AIR TEMPERATURE SENSOR 2 CIRCUIT, LOW VOLTAGE

Note. As intake air temperature increases, IAT sensor resistance decreases.

1. Turn ignition on. Check the IAT sensor 2 in the DATA list with the Honda PGM tester or the HDS. If about 356°F (180°C) or higher, or 0.08 volt or less is indicated, go to next step. If about 356°F (180°C) or higher, or 0.08 volt or less is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at IAT sensor 2 connector and the PCM connector.
2. Turn ignition off. Disconnect IAT 2 2-pin connector. Turn ignition on. Check the IAT sensor 2 in the DATA list with the Honda PGM tester or the HDS. If about 356°F (180°C) or higher, or 0.08 volt or less is indicated, go to next step. If about 356°F (180°C) or higher, or 0.08 volt or less is not indicated, go to step 4.
3. Turn ignition off. Disconnect PCM harness connector "B". (Scheme 4) Check for continuity between ground and IAT 2 2-pin harness connector terminal No. 1. If there is continuity, repair short to ground in Red/Blue wire between IAT sensor 2 and PCM harness connector terminal B53. Go to step 5. If there is not continuity, go to step 6.
4. Replace IAT sensor 2.
5. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0097 is set, check for poor connections or loose terminals at IAT sensor 2 and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.
6. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0097, check for poor connections or loose terminals at IAT sensor 2 and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P0098: INTAKE AIR TEMPERATURE SENSOR 2 CIRCUIT, HIGH VOLTAGE

Note. As intake air temperature increases, IAT sensor resistance decreases.

1. Turn ignition on. Check the IAT sensor 2 in the DATA list with the Honda PGM tester or the HDS. If about -40°F (-40°C) or less, or 4.90 volts or higher is indicated, go to next step. If about -40°F (-40°C) or less, or 4.90 volts or higher is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at IAT sensor 2 connector and the PCM connector.
2. Turn ignition off. Disconnect IAT 2 2-pin connector. Connect the IAT sensor 2 connector terminals 1 and 2 with a fused jumper wire. Turn ignition on. Check the IAT sensor 2 in the DATA list with the Honda PGM tester or the HDS. If about -40°F (-40°C) or less, or 4.90 volts or higher is indicated, go to next step. If about -40°F (-40°C) or less, or 4.90 volts or higher is not indicated, go to step 5.
3. Turn ignition off. Remove jumper wire. Turn ignition on. Measure voltage between ground and IAT 2 2-pin harness connector terminal No. 1. If there is about 5 volts, repair open in Red/Blue wire between IAT sensor 2 and PCM harness connector terminal B53. Go to step 6. If there is not about 5 volts, go to next step.
4. Turn ignition off. Disconnect PCM harness connector "B". (Scheme 4) Check for continuity between PCM harness connector B53 and IAT 2 2-pin harness connector terminal No. 1 (Red/Blue wire). If there is continuity, go to step 7. If there is not continuity, repair open in Red/Blue wire between IAT sensor 2 and PCM harness connector terminal B53. Go to step 6.
5. Replace IAT sensor 2.
6. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0098 is set, check for poor connections or loose terminals at IAT sensor 2 and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.
7. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0098 is set, check for poor connections or loose terminals at IAT sensor 2 and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P0107: MANIFOLD ABSOLUTE PRESSURE SENSOR CIRCUIT, LOW VOLTAGE INPUT

Note. If DTC P0641 is set at the same time as DTC P0107, troubleshoot DTC P0641 first, then recheck for DTC P0107.

1. Turn ignition switch on. With the Honda PGM tester or the HDS, check Manifold Absolute Pressure (MAP) sensor in the DATA list. If MAP sensor data indicates about 3 kPa, or 0.23 volt or less go to next step. If MAP sensor data does not indicates about 3 kPa, or 0.23 volt or less, problem is intermittent. Check for poor connection(s) or loose wire(s) between MAP sensor 3-pin harness connector and PCM.
2. Turn ignition switch off. Disconnect MAP sensor 3-pin harness connector. (Scheme 5) Turn ignition switch on. Check Manifold Absolute Pressure (MAP) sensor in the DATA list. If MAP sensor data indicates about 3 kPa, or 0.23 volt or less go to step 6. If MAP sensor data does not indicates about 3 kPa, or 0.23 volt or less, measure voltage between MAP sensor 3-pin harness connector terminals No. 1 (Yellow/Red wire) and 3 (Green/White wire). See appropriate wiring diagram under ENGINE PERFORMANCE in WIRING DIAGRAMS. If about 5 volts are present, go to step 4. If about 5 volts are not present, go to next step.
3. Turn ignition switch off. Disconnect PCM "A" harness connector. Check for continuity between PCM "A" harness connector terminal A7 and MAP sensor connector terminal No. 1. If there is continuity, go to step 7. If continuity does not exist, repair open in wire between PCM "A" harness connector terminal A7 and MAP sensor connector terminal No. 1. Go to step 5.
4. Replace MAP sensor.
5. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0107 is set, check for poor connections or loose terminals at MAP sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.
6. Turn ignition switch off. Disconnect PCM "A" harness connector. Check for continuity between ground and MAP sensor 3-pin harness connector terminal No. 2 (Green/Red wire). If continuity is present, repair short in wire between MAP sensor 3-pin harness connector terminal No. 3 (Green/Red wire) and PCM "A" harness connector terminal A6. Go to step 5. If continuity is not present, go to next step.
7. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0107, check for poor connections or loose terminals at MAP sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

Scheme 5

DTC P0108: MANIFOLD ABSOLUTE PRESSURE SENSOR CIRCUIT, HIGH VOLTAGE INPUT

1. Turn ignition on. Check the MAP sensor in the DATA list with the Honda PGM tester or the HDS. If about 160 kPa, or 4.49 volts or higher is indicated, go to next step. If about 160 kPa, or 4.49 volts or higher is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at MAP sensor connector and the PCM connector.
2. Turn ignition off. Disconnect MAP 3-pin connector. (Scheme 5) Connect the MAP sensor connector terminals 2 and 3 with a fused jumper wire. Turn ignition on. Check the MAP sensor in the DATA list with the Honda PGM tester or the HDS. If about 160 kPa, or 4.49 volts or higher is indicated, go to next step. 160 kPa, or 4.49 volts or higher is not indicated, go to step 5.
3. Turn ignition off. Remove jumper wire. Turn ignition on. Measure voltage between ground and MAP 3-pin harness connector terminal No. 1 and 3. If there is about 5 volts, go to next step. If there is not about 5 volts, repair open in Red/Yellow wire between IAT sensor 1 and 3. Go to step 6.
4. Turn ignition off. Disconnect PCM harness connector "A". (Scheme 4) Check for continuity between PCM harness connector A6 and MAP sensor 3-pin harness connector terminal No. 2 (Green/Red). If there is continuity, go to step 7. If there is not continuity, repair open in Green/Red wire between MAP sensor and PCM harness connector terminal A6. Go to step 6.
5. Replace MAP sensor.
6. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0108 is set, check for poor connections or loose terminals at MAP sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.
7. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0108, check for poor connections or loose terminals at MAP sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P0112: INTAKE AIR TEMPERATURE SENSOR CIRCUIT, LOW VOLTAGE INPUT

Note. As intake air temperature increases, IAT sensor resistance decreases.

1. Turn ignition on. Check the IAT sensor 1 in the DATA list with the Honda PGM tester or the HDS. If about 356°F (180°C) or higher, or 0.08 volt or less is indicated, go to next step. If about 356°F (180°C) or higher, or 0.08 volt or less is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at IAT sensor 1 connector and the PCM connector.
2. Turn ignition off. Disconnect IAT 2 2-pin connector. Turn ignition on. Check the IAT sensor 1 in the DATA list with the Honda PGM tester or the HDS. If about 356°F (180°C) or higher, or 0.08 volt or less is indicated, go to next step. If about 356°F (180°C) or higher, or 0.08 volt or less is not indicated, go to step 4.
3. Turn ignition off. Disconnect PCM harness connector "A". (Scheme 4) Check for continuity between ground and IAT 1 2-pin harness connector terminal No. 1. If there is continuity, repair short to ground in Red/Yellow wire between IAT sensor 1 and PCM harness connector terminal A24. Go to step 5. If there is not continuity, go to step 6.
4. Replace IAT sensor 1.
5. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0112 is set, check for poor connections or loose terminals at IAT sensor 1 and PCM harness connectors. Go to 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.
6. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0112, check for poor connections or loose terminals at IAT sensor 1 and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P0113: INTAKE AIR TEMPERATURE SENSOR CIRCUIT, HIGH VOLTAGE INPUT

Note. As intake air temperature increases, IAT sensor resistance decreases.

1. Turn ignition on. Check the IAT sensor 1 in the DATA list with the Honda PGM tester or the HDS. If about -40°F (-40°C) or less, or 4.90 volts or higher is indicated, go to next step. If about -40°F (-40°C) or less, or 4.90 volts or higher is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at IAT sensor 1 connector and the PCM connector.
2. Turn ignition off. Disconnect IAT 1 2-pin connector. Connect the IAT sensor connector terminals 1 and 2 with a fused jumper wire. Turn ignition on. Check the IAT sensor 1 in the DATA list with the Honda PGM tester or the HDS. If about -40°F (-40°C) or less, or 4.90 volts or higher is indicated, go to next step. If about -40°F (-40°C) or less, or 4.90 volts or higher is not indicated, go to step 5.
3. Turn ignition off. Remove jumper wire. Turn ignition on. Measure voltage between ground and IAT 1 2-pin harness connector terminal No. 1. If there is about 5 volts, repair open in Red/Yellow wire between IAT sensor 1 and PCM harness connector terminal A24. Go to step 6. If there is not about 5 volts, go to next step.
4. Turn ignition off. Disconnect PCM harness connector "B". (Scheme 4) Check for continuity between PCM harness connector A24 and IAT 1 2-pin harness connector terminal No. 1 (Red/Yellow wire). If there is continuity, go to step 7. If there is not continuity, repair open in Red/Yellow wire between IAT sensor 1 and PCM harness connector terminal A24. Go to step 6.
5. Replace IAT sensor 1.
6. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0113 is set, check for poor connections or loose terminals at IAT sensor 1 and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.
7. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0113, check for poor connections or loose terminals at IAT sensor 1 and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P0116: ENGINE COOLANT TEMPERATURE SENSOR CIRCUIT, RANGE/PERFORMANCE PROBLEM

1. Turn ignition on. Using Honda PGM Tester or the HDS, check ECT sensor in the DATA list. If ECT reading is about 176°F (80°C) or higher, 0.86 volt or less, go to next step. If ECT reading is not about 176°F (80°C) or higher, 0.86 volt or less, go to step 3 .
2. Note current coolant temperature. Turn ignition off. Cool engine for one hour. Using Honda PGM Tester or the HDS, check ECT sensor in the DATA list. If ECT reading changes 5.4°F (3°C) or more, problem is intermittent, system is OK at this time. Check thermostat and cooling system. If ECT reading changes 5.4°F (3°C) or more, go to step 4 .
3. Note current coolant temperature. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle. Using Honda PGM Tester or the HDS, check ECT sensor in the DATA list. If ECT reading changes 5.4°F (3°C) or more, problem is intermittent, system is OK at this time. Check thermostat and cooling system. If ECT reading changes 5.4°F (3°C) or more, go to step 4 .
4. Turn ignition off. Replace the ECT sensor. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) .
5. Allow engine to cool to between 17°F (-7°C) and 86°F (30°C).
6. Start engine, let idle for 20 minutes.
7. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0116 is set, check for poor connections or loose terminals at ECT sensor and PCM harness connectors. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, go to next step.
8. Monitor the OBD STATUS for DTC P0116 in the DTCs menu with the Honda PGM tester or the HDS. If it PASSED, troubleshooting is complete. If it is FAILED, check for poor connections or loose terminals at MAP sensor and PCM harness connectors. Go to step 1 . If it is NOT COMPLETED, go to step 5 and recheck.

DTC P0117: ENGINE COOLANT TEMPERATURE SENSOR CIRCUIT, LOW VOLTAGE

Note. As engine coolant temperature increases, ECT sensor resistance decreases.

1. Turn ignition on. Check the ECT sensor in the DATA list with the Honda PGM tester or the HDS. If about 356°F (180°C) or higher, or 0.08 volt or less is indicated, go to next step. If about 356°F (180°C) or higher, or 0.08 volt or less is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at ECT sensor connector and the PCM connector.
2. Turn ignition off. Disconnect ECT 2-pin connector. Turn ignition on. Check the ECT sensor in the DATA list with the Honda PGM tester or the HDS. If about 356°F (180°C) or higher, or 0.08 volt or less is indicated, go to next step. If about 356°F (180°C) or higher, or 0.08 volt or less is not indicated, go to step 4.
3. Turn ignition off. Disconnect PCM harness connector "A". (Scheme 4) Check for continuity between ground and ECT 2-pin harness connector terminal No. 1. If there is continuity, repair short to ground in Red/White wire between ECT sensor and PCM harness connector terminal A4. Go to step 5. If there is not continuity, go to step 6.
4. Replace ECT sensor.
5. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0117 is set, check for poor connections or loose terminals at ECT sensor and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.
6. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0117, check for poor connections or loose terminals at ECT sensor and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P0118: ENGINE COOLANT TEMPERATURE SENSOR CIRCUIT, HIGH VOLTAGE INPUT

Note. As engine coolant temperature increases, ECT sensor resistance decreases.

1. Turn ignition on. Check the ECT sensor in the DATA list with the Honda PGM tester or the HDS. If about -40°F (-40°C) or less, or 4.90 volts or higher is indicated, go to next step. If about -40°F (-40°C) or less, or 4.90 volts or higher is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at ECT sensor connector and the PCM connector.
2. Turn ignition off. Disconnect ECT sensor 2-pin connector. Connect the ECT sensor connector terminals 1 and 2 with a fused jumper wire. Turn ignition on. Check the ECT sensor in the DATA list with the Honda PGM tester or the HDS. If about -40°F (-40°C) or less, or 4.90 volts or higher is indicated, go to next step. If about -40°F (-40°C) or less, or 4.90 volts or higher is not indicated, go to step 5.
3. Turn ignition off. Remove jumper wire. Turn ignition on. Measure voltage between ground and ECT sensor 2-pin harness connector terminal No. 1. If there is about 5 volts, repair open in Red/White wire between ECT sensor and PCM harness connector terminal A4. Go to step 6. If there is not about 5 volts, go to next step.
4. Turn ignition off. Disconnect PCM harness connector "B". (Scheme 4) Check for continuity between PCM harness connector A4 and ECT sensor 2-pin harness connector terminal No. 1 (Red/White wire). If there is continuity, go to step 7. If there is not continuity, repair open in Red/White wire between ECT sensor and PCM harness connector terminal A4. Go to step 6.
5. Replace ECT sensor.
6. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0118 is set, check for poor connections or loose terminals at ECT sensor and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.
7. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0118, check for poor connections or loose terminals at ECT sensor and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P0122: THROTTLE POSITION SENSOR 1 CIRCUIT, LOW VOLTAGE

Note. TP sensor is an integral part of throttle body and is not sold separately.

1. Turn ignition on. Check the TP SENSOR 1 in the DATA list with the Honda PGM tester or the HDS. If about 0.28 volt or lower is indicated, go to next step. If about 0.28 volt or lower is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at TP sensor 1 connector (at throttle actuator control module) and the PCM connector.
2. Turn ignition off. Replace throttle body assembly.
3. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0122 is set, check for poor connections or loose terminals at TP sensor 1 connector and PCM harness connectors. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.

DTC P0123: THROTTLE POSITION SENSOR CIRCUIT, HIGH VOLTAGE

Note. TP sensor is an integral part of throttle body and is not sold separately.

1. Turn ignition on. Check the TP SENSOR 1 in the DATA list with the Honda PGM tester or the HDS. If about 4.75 volts or higher is indicated, go to next step. If about 4.75 volts or higher is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at TP sensor 1 connector (at throttle actuator control module) and the PCM connector.
2. Turn ignition off. Replace throttle body assembly.
3. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0123 is set, check for poor connections or loose terminals at TP sensor 1 connector and PCM harness connectors. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.

DTC P0125: ENGINE COOLANT TEMPERATURE SENSOR, SLOW RESPONSE

1. Start engine and let it idle.
2. Check ECT SENSOR in the DATA list with the Honda PGM tester or the HDS. If about 86°F (30°C) or less, or 2.61 volts or higher is indicated, go to next step. If about 86°F (30°C) or less, or 2.61 volts or higher is not indicated, problem is intermittent, system is OK at this time. Check thermostat and cooling system.
3. Let engine idle for 15 minutes. Check ECT SENSOR in the DATA list with the Honda PGM tester or the HDS. If about 86°F (30°C) or less, or 2.61 volts or higher is indicated, go to next step. If about 86°F (30°C) or less, or 2.61 volts or higher is not indicated, problem is intermittent, system is OK at this time. Check thermostat and cooling system.
4. Turn ignition off. Replace ECT sensor.
5. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) .
6. Allow engine to cool to between 19°F (-7°C) and 86°F (30°C).
7. Start engine and let engine idle for 20 minutes.
8. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0125 is set, check for poor connections at ECT sensor and PCM. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, go to next step.
9. Monitor the OBD STATUS for DTC P0125 in the DTCs menu with the Honda PGM tester or the HDS. If it PASSED, troubleshooting is complete. If it is FAILED, check for poor connections at ECT sensor and PCM. Go to step 1 . If it is NOT COMPLETED, go to step 6 and recheck.

DTC P0128: COOLING SYSTEM MALFUNCTION

Note. If DTCs P0112, P0113, P0116, P0117, P0118, P0300, P0301-P0306, P0335, P0339, P0385, P0389, P2227-P2229, P2646-P2649, P0506, or P0507 are stored, troubleshoot these DTCs first. DTC P0128 can also set when hood is opened while engine is running.

1. Turn ignition on. Do the DTC CLEAR in the CLEAR menu with the Honda PGM tester or the HAS. Turn blower switch off. Turn A/C off.
2. Check FAN CTRL in the DATA list with the Honda PGM tester or the HDS. If the fan is off, go to next step. If the fan is not off, wait until FAN CTRL is off Go to next step.
3. Check the ECT sensor in the DATA list with the Honda PGM tester or the HDS, then check radiator fan operation. If the fan keeps running when engine coolant temperature reaches 158°F (70°C) check radiator fan circuits, fan relay circuits and the fan relay. If circuits are OK , go to step 10 . If the fan does not keep running when engine coolant temperature reaches 158°F (70°C), go to next step.
4. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle. Turn ignition off.
5. Turn ignition on. Do the RADIATOR FAN test in the DATA list with the Honda PGM tester or the HDS for 20 minutes. Check ECT SENSOR in the DATA list with the Honda PGM tester or the HDS. If about 140°F (60°C) or less, 1.25 volt or more is measured, problem is intermittent, system is OK at this time. If about 140°F (60°C) or less, 1.25 volt or more is not measured, go to next step.
6. Turn ignition off. Allow engine to cool to between 19°F (-7°C) and 86°F (30°C). Replace thermostat.
7. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) .
8. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0128 is set, check the cooling system. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, go to next step.
9. Monitor the OBD STATUS for DTC P0128 in the DTCs menu with the Honda PGM tester or the HDS. If it PASSED, troubleshooting is complete. If it is FAILED, check the cooling system. Go to step 1 . If it is NOT COMPLETED, go to step 8 and recheck.
10. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Allow engine to cool to between 19°F (-7°C) and 86°F (30°C). Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0128 is set, check for poor connections or loose terminals at ECT sensor and PCM harness connectors. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P0133 OR DTC P0153

Code Definition

1. DTC P0133: Rear Air Fuel Ratio Sensor Circuit Slow Response (Bank 1, Sensor 1)
2. DTC P0153: Front Air Fuel Ratio Sensor Circuit Slow Response (Bank 2, Sensor 1)

Note. This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear (A/F) ratio sensor terminals will precede Front A/F ratio sensor terminals. Also, Front A/F ratio sensor terminal information will be enclosed in parantheses ( ).

Note. If DTC P0139 and/or (P0159) is set at the same time as DTC P0133 and/or (P0153), troubleshoot DTC P0139 and/or (P0159) first, then recheck for DTC P0133 and/or (P0153).

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle
3. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). A/T in "D" position. Vehicle speed at 30 MPH or more and engine speed at 1200-2250 RPM.
4. Using Honda PGM Tester or the HDS, check the AF FB AVE in the DATA list. If the value is 0.8-1.2, go to next step. If the value is not 0.8-1.2. Go to step 3 and recheck.
5. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P0133 and/or (P0153) in the DTCs menu. If it is PASSED, problem is intermittent, system is OK at this time. If it FAILED, go to next step. If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION, go to step 1 and recheck.
6. Turn ignition off.
7. Replace Air Fuel Ratio sensor.
8. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) .
9. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle
10. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). A/T in "D" position. Vehicle speed at 30 MPH or more and engine speed at 1200-2250 RPM.
11. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0133 and/or (P0153) are set, check for poor connections or loose terminals at A/F sensor (Sensor 1) and PCM connector. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, go to next step.
12. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P0133 and/or (P0153) in the DTCs menu. If it is PASSED, troubleshooting is complete. If it FAILED, check for poor connections or loose terminals at A/F sensor (Sensor 1) and PCM connector Go to step 1 . If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION, go to step 9 and recheck.

DTC P0134 OR DTC P0154

Code Definition

1. DTC P0134: Rear Air Fuel Ratio Sensor Heater System Malfunction (Bank 1, Sensor 1)
2. DTC P0154: Front Air Fuel Ratio Sensor Heater System Malfunction (Bank 2, Sensor 1)

Note. This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear (A/F) ratio sensor terminals will precede Front A/F ratio sensor terminals. Also, Front A/F ratio sensor terminal information will be enclosed in parantheses ( ).

Note. If DTC P1153, P1155, (P1173) and/or (P1175) is set at the same time as DTC P0134 and/or (P0154), troubleshoot DTC P1153, P1155, (P1173) and/or (P1175) first, then recheck for DTC P0134 and/or (P0154).

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine with no load (A/T in Park or Neutral). Run until the radiator fan comes on, then let engine idle.
3. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0134 and/or (P0154) are set, go to next step. If DTCs P0134 and/or (P0154) are not set, check for poor connections or loose terminals at A/F sensor (Sensor 1) and PCM connector.
4. Turn ignition off.
5. Replace Air Fuel Ratio sensor.
6. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) .
7. Start engine with no load (A/T in Park or Neutral). Run until the radiator fan comes on, then let engine idle.
8. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0134 and/or (P0154) are set, check for poor connections or loose terminals at A/F sensor (Sensor 1) and PCM connector, go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, go to next step.
9. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P0134 and/or (P0154) in the DTCs menu. If it is PASSED, troubleshooting is complete. If it FAILED, check for poor connections or loose terminals at A/F sensor (Sensor 1) and PCM connector Go to step 1 . If it is NOT COMPLETED, go to step 7 and recheck.

DTC P0135 OR DTC P0155

Code Definition

1. DTC P0135: Rear Air Fuel Ratio Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)
2. DTC P0155: Front Air Fuel Ratio Sensor Heater Circuit Malfunction (Bank 2, Sensor 1)

Note. This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear (A/F) ratio sensor terminals will precede Front A/F ratio sensor terminals. Also, Front A/F ratio sensor terminal information will be enclosed in parantheses ( ).

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine with no load (A/T in Park or Neutral). Run until the radiator fan comes on, then let engine idle.
3. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0135 and/or (P0155) are set, go to next step. If DTCs P0135 and/or (P0155) are not set, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at A/F sensor (Sensor 1) and PCM connector.
4. Turn ignition switch off. Check No. 9 LAFHT (15-amp) fuse in the under-hood sub-fuse box. If it is blown, repair short in wire between Air Fuel Ratio sensor and A/F sensor relay and the fuse. Go top step 15. If fuse is not blown, go to next step.
5. Disconnect the A/F sensor 8-pin harness connector. (Scheme 6) At component side measure resistance between the A/F sensor 8-pin harness connector terminals No. 1 and 2. If there is between 2.5-3.2 ohms at room temperature, go to next step. If there is not between 2.5-3.2 ohms at room temperature, go to step 14.
6. Check for continuity between ground and each A/F sensor 8-pin harness connector terminal individually. If there is continuity, go to step 14. If there is no continuity, go to next step.
7. Check for continuity between the A/F sensor 8-pin harness connector terminal No. 1 and the rest, 3, 4, 6, 7 and 8 individually. If there is continuity, repair short in wire between go to step 14. If there is no continuity, go to next step.
8. Disconnect PCM harness connector "A". (Scheme 4) Check continuity between ground and PCM harness connector "A" terminal A57 (A58). If continuity is present, repair short in wire(s) between PCM harness connector "A" terminal A57 (A58) and A/F sensor (Sensor 1). Go to step 15. If continuity is not present, go to next step.
9. With a fused jumper wire, connect A/F sensor (Sensor 1) connector terminal No. 2 to ground. Check continuity between ground and PCM harness connector "A" terminal A57 (A58). If continuity is present, go to next step. If continuity is not present, repair open in wire(s) between PCM harness connector "A" terminal A57 (A58) and A/F sensor (Sensor 1). Go to step 15.
10. With a fused jumper wire, connect A/F sensor (Sensor 1) connector terminal No. 1 to ground. Remove the A/F sensor relay. Check continuity between ground and A/F sensor relay harness connector terminal No. 2 (White/Black wire). If continuity is present, go to next step. If continuity is not present, repair open in wire between A/F sensor (Sensor 1) and the A/F sensor relay. Go to step 15.
11. Disconnect PCM harness connector "B". (Scheme 4) Check continuity between ground and PCM harness connector "B" terminal B10 (Orange wire). If continuity is present, repair short in wire between PCM harness connector "B" terminal B10 (Orange wire) and A/F sensor relay. Go to step 15. If continuity is not present, go to next step.
12. Check continuity between A/F sensor relay terminal No. 3 and PCM harness connector "B" terminal B10 (Orange wire). If continuity is present, go to next step. If continuity is not present, repair open in wire between PCM harness connector "B" terminal B10 (Orange wire) and A/F sensor relay. Go to step 15.
13. Test A/F sensor relay. If the A/F sensor relay is OK, go to step 18. If the A/F sensor relay is not OK, replace the A/F sensor relay. Go to step 15.
14. Replace A/F sensor (Sensor 1).
15. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
16. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0135 and/or (P0155) are set, check for poor connections or loose terminals at A/F sensor (Sensor 1) and PCM connector, go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, go to next step.
17. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P0135 and/or (P0155) in the DTCs menu. If it is PASSED, troubleshooting is complete. If it FAILED, check for poor connections or loose terminals at A/F sensor (Sensor 1) and PCM connector Go to step 1. If it is NOT COMPLETED, go to step 15 and recheck.
18. Update the PCM if it does not have the latest software, or substitute a know-good PCM.
19. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0135 and/or (P0155) are set, check for poor connections or loose terminals at A/F sensor (Sensor 1) and PCM connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, PCM was updated, troubleshooting is done. If PCM was substituted, replace the original PCM.

Scheme 6

DTC P0137 OR DTC P0157

Code Definition

1. DTC P0137: Rear Secondary Heated Oxygen Sensor Circuit Low Voltage (Bank 1, Sensor 2)
2. DTC P0157: Front Secondary Heated Oxygen Sensor Circuit Low Voltage (Bank 2, Sensor 2)

Note. This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear (A/F) ratio sensor terminals will precede Front A/F ratio sensor terminals. Also, Front A/F ratio sensor terminal information will be enclosed in parantheses ( ).

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle.
3. Using Honda PGM Tester or the HDS, check the AF FB AVE (LT FUEL TRIM) in the DATA list. If the value is 1.00 or more, go to next step. If the value is not 1.00 or more, check for poor connections or loose terminals at secondary HO2 sensor (Sensor 2) and PCM connectors. Go to step 1.
4. Using Honda PGM Tester or the HDS, check the HO2S S2 in the DATA list. If the voltage is 0.29 volt or less, go to next step. If the voltage is not 0.29 volt or less, go to step 7.
5. Turn ignition off. Disconnect the secondary HO2S (Sensor 2) 4-pin connector. (Scheme 7) Go to next step.
6. Using Honda PGM Tester or the HDS, check the HO2S S2 in the DATA list. If the voltage is 0.29 volt or less, go to step 9. If the voltage is not 0.29 volt or less, go to step 11.
7. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). A/T in "D" position. Engine speed at 2000-3000 RPM. Drive vehicle about 10 minutes, then decelerate (with throttle fully closed) for 5 seconds.
8. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P0137 and/or (P0157) in the DTCs menu. If it is PASSED, problem is intermittent, system is OK at this time. If it FAILED, go to step 11. If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION, go to step 7 and recheck.
9. Turn ignition off.
10. Disconnect PCM harness connector "A". (Scheme 4) Check for continuity between ground and secondary HO2S (Sensor 2) 4-pin connector terminal No. 1. If there is continuity, repair short in wire between PCM harness connector "A" terminal A21 (A22) and secondary HO2S (Sensor 2). Go to step 14.
11. Turn ignition off.
12. Replace secondary HO2S (Sensor 2). Go to step 14.
13. Reconnect PCM harness connector "A". Go to next step.
14. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
15. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle
16. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). A/T in "D" position. Engine speed at 2000-3000 RPM. Drive vehicle about 10 minutes, then decelerate (with throttle fully closed) for 5 seconds.
17. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0137 and/or (P0157) are set, check for poor connections or loose terminals at secondary HO2S (Sensor 2) and PCM connector, go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, go to next step.
18. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P0137 and/or (P0157) in the DTCs menu. If it is PASSED, troubleshooting is complete. If it FAILED, check for poor connections or loose terminals at secondary HO2S (Sensor 2) and PCM connector Go to step 1. If it is NOT COMPLETED, go to step 15 and recheck.
19. Update the PCM if it does not have the latest software, or substitute a know-good PCM.
20. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle
21. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). A/T in "D" position. Engine speed at 2000-3000 RPM. Drive vehicle about 10 minutes, then decelerate (with throttle fully closed) for 5 seconds.
22. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0137 and/or (P0157) are set, check for poor connections or loose terminals at secondary HO2S (Sensor 2) and PCM connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, PCM was updated, troubleshooting is done. If PCM was substituted, replace the original PCM.

DTC P0138 OR DTC P0158

Code Definition

1. DTC P0138: Rear Secondary Heated Oxygen Sensor Circuit High Voltage (Bank 1, Sensor 2)
2. DTC P0158: Front Secondary Heated Oxygen Sensor Circuit High Voltage (Bank 2, Sensor 2)

Note. This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear (A/F) ratio sensor terminals will precede Front A/F ratio sensor terminals. Also, Front A/F ratio sensor terminal information will be enclosed in parantheses ( ).

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle.
3. Using Honda PGM Tester or the HDS, check the AF FB AVE (LT FUEL TRIM) in the DATA list. If the value is 1.00 or more, go to next step. If the value is not 1.00 or more, check for poor connections or loose terminals at secondary HO2 sensor (Sensor 2) and PCM connectors. Go to step 1.
4. Using Honda PGM Tester or the HDS, check the HO2S S2 in the DATA list. If the voltage is 0.75 volt or more, go to step 7. If the voltage is not 0.75 volt or more, go to next step.
5. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). A/T in "D" position. Engine speed at 2000-3000 RPM. Drive vehicle about 10 minutes, then decelerate (with throttle fully closed) for 5 seconds.
6. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P0138 and/or (P0158) in the DTCs menu. If it is PASSED, problem is intermittent, system is OK at this time. If it FAILED, go to step 12. If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION, go to step 5 and recheck.
7. Turn ignition off. Disconnect the secondary HO2S (Sensor 2) 4-pin connector. (Scheme 7) Go to next step.
8. With a fused jumper wire, connect secondary HO2S (Sensor 2) 4-pin connector terminals No. 1 and 2. Go to next step.
9. Turn ignition on. Using Honda PGM Tester or the HDS, check the HO2S S2 in the DATA list. If the voltage is 0.75 volt or more, go to next step. If the voltage is not 0.75 volt or more, go to step 12.
10. Turn ignition off. Disconnect PCM harness connector "A". (Scheme 4) Check for continuity between PCM harness connector "A" terminals A21 and A28 and/or (A22) and A28. If there is continuity, go to step 19. If there is no continuity, go to next step.
11. Remove the jumper wire connected to secondary HO2S (Sensor 2) 4-pin connector. Check for continuity between PCM harness connector "A" terminals A21 (A22) and secondary HO2S (Sensor 2) 4-pin connector terminals No. 1. If there is continuity, repair open in wire between PCM harness connector "A" terminal A28 and secondary HO2S (Sensor 2). Go to step 14. If there is no continuity, repair wire between PCM harness connector "A" terminals A21 (A22) and secondary HO2S (Sensor 2). Go to step 14.
12. Turn ignition off.
13. Replace secondary HO2S (Sensor 2).
14. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
15. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle.
16. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). A/T in "D" position. Engine speed at 2000-3000 RPM. Drive vehicle about 10 minutes, then decelerate (with throttle fully closed) for 5 seconds.
17. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0138 and/or (P0158) are set, check for poor connections or loose terminals at secondary HO2S (Sensor 2) and PCM connector, go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, go to next step.
18. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for P0138 and/or (P0158) in the DTCs menu. If it is PASSED, troubleshooting is complete. If it FAILED, check for poor connections or loose terminals at secondary HO2S (Sensor 2) and PCM connector Go to step 1. If it is NOT COMPLETED, go to step 14 and recheck.
19. Update the PCM if it does not have the latest software, or substitute a know-good PCM.
20. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle
21. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). A/T in "D" position. Engine speed at 2000-3000 RPM. Drive vehicle about 10 minutes, then decelerate (with throttle fully closed) for 5 seconds.
22. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0138 and/or (P0158) are set, check for poor connections or loose terminals at secondary HO2S (Sensor 2) and PCM connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, PCM was updated, troubleshooting is done. If PCM was substituted, replace the original PCM.

DTC P0139 OR DTC P0159

Code Definition

1. DTC P0139: Rear Secondary Heated Oxygen Sensor Slow Response (Bank 1, Sensor 2)
2. DTC P0159: Front Secondary Heated Oxygen Sensor Slow Response (Bank 2, Sensor 2)

Note. This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear (A/F) ratio sensor terminals will precede Front A/F ratio sensor terminals. Also, Front A/F ratio sensor terminal information will be enclosed in parantheses ( ).

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle.
3. Test drive vehicle with throttle fully opened, then decelerate with throttle fully closed for 3 seconds.
4. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P0139 and/or (P0159) in the DTCs menu. If it is PASSED, problem is intermittent, system is OK at this time. If it FAILED, go to next step. If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION, go to step 2 and recheck.
5. Turn ignition off.
6. Replace secondary HO2S (Sensor 2).
7. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) .
8. Test drive vehicle with throttle fully opened, then decelerate with throttle fully closed for 3 seconds.
9. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0139 and/or (P0159) are set, check for poor connections or loose terminals at secondary HO2S (Sensor 2) and PCM connector, go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, go to next step.
10. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for P0139 and/or (P0159) in the DTCs menu. If it is PASSED, troubleshooting is complete. If it FAILED, check for poor connections or loose terminals at secondary HO2S (Sensor 2) and PCM connector Go to step 1 . If it is NOT COMPLETED, go to step 8 and recheck.

DTC P0141 OR DTC P0161

Code Definition

1. DTC P0141: Rear Secondary Heated Oxygen Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)
2. DTC P0161: Front Secondary Heated Oxygen Sensor Heater Circuit Malfunction (Bank 2, Sensor 2)

Note. This test covers both Front and Rear secondary HO2S (Sensor 2). The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear secondary HO2S (Sensor 2) terminals will precede Front secondary HO2S (Sensor 2) terminals. Also, Front secondary HO2S (Sensor 2) terminal information will be enclosed in parantheses ( ).

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine with no load (A/T in Park or Neutral). Run until the radiator fan comes on, then let engine idle.
3. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0141 and/or (P0161) are set, go to next step. If DTCs P0141 and/or (P0161) are not set, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at secondary HO2S (Sensor 2) and PCM connector.
4. Turn ignition switch off. Check No. 9 LAFHT (15-amp) fuse in the under-hood sub-fuse box. If it is blown, repair short in wire between secondary HO2S (Sensor 2) and A/F sensor relay and the fuse. Go top step 14. If fuse is not blown, go to next step.
5. Disconnect the secondary HO2S (Sensor 2) 4-pin harness connector. (Scheme 7) At component side, measure resistance between the secondary HO2S (Sensor 2) 4-pin harness connector terminals No. 3 and 4. If there is between 5.4-6.6 ohms at room temperature, go to next step. If there is not between 5.4-6.6 ohms at room temperature, go to step 13.
6. Check for continuity between ground and secondary HO2S (Sensor 2) 4-pin harness connector terminal No. 3 and 4 individually. If there is continuity, go to step 13. If there is no continuity, go to next step.
7. Disconnect PCM harness connector "A". (Scheme 4) Check continuity between ground and PCM harness connector "A" terminal A59 (A60). If continuity is present, repair short in wire(s) between PCM harness connector "A" terminal A59 (A60) and secondary HO2S (Sensor 2). Go to step 14. If continuity is not present, go to next step.
8. With a fused jumper wire, connect secondary HO2S (Sensor 2) connector terminal No. 3 to ground. Check continuity between ground and PCM harness connector "A" terminal A59 (A60). If continuity is present, go to next step. If continuity is not present, repair open in wire(s) between PCM harness connector "A" terminal A59 (A60) and secondary HO2S (Sensor 2). Go to step 14.
9. With a fused jumper wire, connect secondary HO2S (Sensor 2) connector terminal No. 4 to ground. Remove the A/F sensor relay. Check continuity between ground and A/F sensor relay harness connector terminal No. 2 (White/Black wire). If continuity is present, go to next step. If continuity is not present, repair open in wire between secondary HO2S (Sensor 2) and the A/F sensor relay. Go to step 14.
10. Disconnect PCM harness connector "B". (Scheme 4) Check continuity between ground and PCM harness connector "B" terminal B10 (Orange wire). If continuity is present, repair short in wire between PCM harness connector "B" terminal B10 (Orange wire) and A/F sensor relay. Go to step 14. If continuity is not present, go to next step.
11. With a fused jumper wire, connect A/F sensor relay harness connector terminal No. 3 (Orange wire) to ground. Check continuity between ground and PCM harness connector "B" terminal B10 (Orange wire). If continuity is present, go to next step. If continuity is not present, repair open in wire between PCM harness connector "B" terminal B10 (Orange wire) and A/F sensor relay. Go to step 13.
12. Test A/F sensor relay. If the A/F sensor relay is OK, go to step 17. If the A/F sensor relay is not OK, replace the A/F sensor relay. Go to step 14.
13. Replace secondary HO2S (Sensor 2).
14. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
15. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0141 and/or (P0161) are set, check for poor connections or loose terminals at secondary HO2S (Sensor 2) and PCM connector, go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, go to next step.
16. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P0141 and/or (P0161) in the DTCs menu. If it is PASSED, troubleshooting is complete. If it FAILED, check for poor connections or loose terminals at secondary HO2S (Sensor 2) and PCM connector Go to step 1. If it is NOT COMPLETED, go to step 15 and recheck.
17. Update the PCM if it does not have the latest software, or substitute a know-good PCM.
18. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0141 and/or (P0161) are set, check for poor connections or loose terminals at secondary HO2S (Sensor 2) and PCM connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, PCM was updated, troubleshooting is done. If PCM was substituted, replace the original PCM.

Scheme 7

DTC P0171, DTC P0172, DTC P0174 OR DTC P0175

Code Definition

1. DTC P0171: Rear Bank (Bank 1) Fuel System Too Lean
2. DTC P0172: Rear Bank (Bank 1) Fuel System Too Rich
3. DTC P0174: Front Bank (Bank 2) Fuel System Too Lean
4. DTC P0175: Front Bank (Bank 2) Fuel System Too Rich

Note. If DTCs P0107, P0108, P0133, P0134, P0135, P0137, P0138, P0139, P0141, P0153, P0154, P0155, P0157, P0158, P0159, P0161, P0401, P0404, P0406, P1128, P1129, P2195, P2197, P2237, P2238,P2240, P2241, P2243, P2245, P2247, P2249, P2251, P2252, P2254, P2255, P2279, P2413, P2627, P2628, P2630, P2631, P2646, P2647, P2648, P2649, P2A00, or P2A03 are also set, troubleshoot these before proceeding.

1. Check fuel pressure. See «FUEL PRESSURE (MDX)»(ref-151684-S16405542492003032100000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. If fuel pressure is okay, check valve clearances and adjust if necessary. See VALVE CLEARANCE in ON-VEHICLE ADJUSTMENTS «MDX, 3.2CL & 3.2TL»(/acura/mdx/i-2000-2006/remont/adjustments/#engine-controls-on-vehicle-adjustments__mdx-32cl-32tl) article. If valve clearance is OK, replace fuel injectors. Go to next step. If fuel pressure is not OK, check the following. Go to next step. If fuel pressure is too high, check fuel pressure regulator and fuel return line. Repair as necessary. If fuel pressure is too low, check fuel pump, fuel feed line, fuel filter and fuel pressure regulator. Repair as necessary.
2. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) .
3. Start engine and run at 3000 RPM, with no load (in park or neutral) until radiator fan comes on then let engine idle.
4. Test drive under the following conditions: Engine coolant temperature more than 158°F (70°C). A/T in "D" position. Drive at a steady speed between 25-55 MPH for 5 minutes, then drive at a steady speed between 15-75 MPH for 15 minutes NOTE: DTC P0171, P0172, P0174 and/or P0175 may take up to 40 minutes of test driving to set. With the Honda PGM tester or the HDS, monitor the long term fuel trim (LTFT) or air fuel feed back AVE (AF FB AVE) for 15 minutes of driving. If the fuel trim/ AF AVE stays at about 1.0 (0.0 percent) there is no problem at this time.
5. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0171, P0172, P0174 and/or P0175 are set, go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.

DTC P0201, DTC P0202, DTC P0203, DTC P0204, DTC P0205 OR DTC P0206

Code Definition

1. DTC P0201: No. 1 Fuel Injector Circuit Malfunction
2. DTC P0202: No. 2 Fuel Injector Circuit Malfunction
3. DTC P0203: No. 3 Fuel Injector Circuit Malfunction
4. DTC P0204: No. 4 Fuel Injector Circuit Malfunction
5. DTC P0205: No. 5 Fuel Injector Circuit Malfunction
6. DTC P0206: No. 6 Fuel Injector Circuit Malfunction

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine with no load (A/T in Park or Neutral), then let it idle.
3. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0201, P0202, P0203, P0204, P0205 and/or P0206 are set, go to next step. If there are no Temporary DTCs or DTCs set, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at appropriate fuel injector and PCM connector.
4. Turn ignition off. Disconnect PCM harness connector "A". (Scheme 4) Go to next step.
5. Turn ignition on. Measure voltage between ground and appropriate PCM connector terminal. See «DTC/PCM "A" HARNESS CONNECTOR TERMINAL IDENTIFICATION»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics). If there is battery voltage, go to step 16. If there is no battery voltage, go to next step. DTC/PCM "A" HARNESS CONNECTOR TERMINAL IDENTIFICATION Problem Cylinder DTC PCM Connector Terminal Wire Color No. 1 P0201 A61 Brown No. 2 P0202 A62 Red No. 3 P0203 A63 Blue No. 4 P0204 A64 Yellow No. 5 P0205 A65 Black/Red No. 6 P0206 A66 White/Blue
6. Remove intake manifold. See INTAKE MANIFOLD «REMOVAL & INSTALLATION»(ref-98284-S05190566582001052100000) in ENGINES article.
7. Disconnect injector 2-pin harness connector from the suspect cylinder.
8. Turn ignition on. Measure voltage between ground and injector 2-pin harness connector terminal No. 1. If there is battery voltage, go to next step. If there is no battery voltage, repair open in wire between injector and PGM-FI main relay 1. Go to step 17.
9. Turn ignition off. Check for continuity between ground and the appropriate PCM connector terminal. See «DTC/PCM "A" HARNESS CONNECTOR TERMINAL IDENTIFICATION»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics). If there is continuity, repair short in wire between PCM and injector. Go to step 17. If there is no continuity, go to next step.
10. With a fused jumper, connector the appropriate injector connector terminal No. 2 to ground. See «DTC/PCM "A" HARNESS CONNECTOR TERMINAL IDENTIFICATION»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics). Go to next step.
11. Check for continuity between ground and the appropriate PCM connector terminal. If there is continuity, go to next step. If there is no continuity, repair open in wire between PCM and injector. Go to step 17.
12. Measure resistance between injector 2-pin connector terminals No. 1 and 2 (component side). If there is about 10-13 ohms, go to next step. If resistance is not as specified, replace injector. Go to step 17.
13. Substitute a known-good injector to the problem cylinder. Reinstall intake manifold.
14. Reconnect PCM harness connector "A". Start engine and let idle for 2 minutes.
15. Test drive vehicle for several minutes in the range of the recorded freeze frames.
16. Using the Honda PGM Tester or the HDS, check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE in the DATA list for 10 minutes. If it does show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, go to step 21. If it does not show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, replace the original injector. Go to next step.
17. Reconnect PCM harness connector "A". Reconnect injector harness connectors.
18. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
19. Test drive vehicle for several minutes in the range of the recorded freeze frames.
20. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0201, P0202, P0203, P0204, P0205 and/or P0206 are set, check for poor connections or loose terminals at fuel injector and PCM connector. Go to «DTC P0201, DTC P0202, DTC P0203, DTC P0204, DTC P0205 OR DTC P0206»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__dtc-p0201-dtc-p0202-dtc-p0203). If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is done.
21. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
22. Test drive vehicle for several minutes in the range of the recorded freeze frames.
23. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0201, P0202, P0203, P0204, P0205 and/or P0206 are set, check for poor connections or loose terminals at fuel injector and PCM connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P0222: THROTTLE POSITION SENSOR 2 CIRCUIT, LOW VOLTAGE

1. Turn ignition on. Check the TP SENSOR 2 in the DATA list with the Honda PGM tester or the HDS. If about 0.18 volt or lower is indicated, go to next step. If about 0.18 volt or lower is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at TP sensor 2 connector (at throttle actuator control module) and the PCM connector.
2. Turn ignition off. Replace throttle body assembly.
3. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0222 is set, check for poor connections or loose terminals at TP sensor 2 connector and PCM harness connectors. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.

DTC P0223: THROTTLE POSITION SENSOR 2, CIRCUIT, HIGH VOLTAGE

1. Turn ignition on. Check the TP SENSOR 2 in the DATA list with the Honda PGM tester or the HDS. If about 4.84 volts or higher is indicated, go to step next step. If about 4.84 volts or higher is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at TP sensor 2 connector (at throttle actuator control module) and the PCM connector.
2. Turn ignition off. Replace throttle body assembly.
3. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0223 is set, check for poor connections or loose terminals at TP sensor 2 connector and PCM harness connectors. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.

DTC P0300: RANDOM MISFIRE & WITH DTC P0301-DTC P0306

Note. If misfire is frequent enough to trigger detection of increased emissions during 2 consecutive driving cycles, the MIL will come on and DTC P0300 (and some combination of DTCs P0301-P0306) will be stored.

Note. If misfire is frequent enough to damage the catalytic converter, the MIL will blink whenever the misfire occurs and DTC P0300 (and some combination of DTCs P0301-P0306) will be stored. When the misfire stops, the MIL will remain on.

Note. If DTCs P0107, P0108, P0171, P0172, P0401, P0404, P0406, P0506, P0507, P0335, P0339, P0340, P0344, P0385, P0389, P1128, P1129 and/or P2413 are set, troubleshoot these DTCs before trouble shooting random misfire DTCs.

1. Special tools required: Pressure Gauge Adapter (07NAJ-P07010A) A/T Low Pressure Gauge With Panel (07406-0070300) A/T Pressure Hose (07406-0020201) A/T Pressure Hose, 2210 mm (07MAJ-PY4011A) A/T Pressure Adapter (07MAJ-PY40120) Oil Pressure Hose (07ZAJ-S5AA200)
2. Note the following freeze frame data: Engine speed. Vehicle speed. Throttle position. CLV. Gear position.
3. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
4. Start engine with no load (A/T in Park or Neutral), then let it idle.
5. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0301, P0302, P0303, P0304, P0305 or P0306 in the DTCs menu. If it is PASSED, go to next step. If it FAILED. Go to step 10. If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION, wait for several minutes and recheck.
6. Using the Honda PGM Tester or the HDS, check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE in the DATA list for 10 minutes. If it does show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, go to step 10. If it does not show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, go to next step.
7. Test drive vehicle for several minutes in the range of the recorded freeze frames.
8. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0301, P0302, P0303, P0304, P0305 or P0306 in the DTCs menu. If it is PASSED, go to next step. If it FAILED. Go to 10. If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION, go to step 7 and recheck.
9. Using the Honda PGM Tester or the HDS, check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE in the DATA list for 10 minutes. If it does show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, go to next step. If it does not show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, problem is intermittent, system is OK at this time.
10. Turn ignition off.
11. Check fuel quality. If the fuel quality is good, go to next step. If the fuel quality is not good, drain the tank and fill it with known-good fuel. Go to step 18.
12. Clean spark plugs.
13. Test drive vehicle for several minutes in the range of the recorded freeze frames.
14. Using the Honda PGM Tester or the HDS, check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE in the DATA list for 10 minutes. If it does show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, go to next step. If it does not show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, go to step 18.
15. Check fuel pressure. See «FUEL PRESSURE TESTING - MDX»(ref-151684-S16405542492003032100000) under FUEL SYSTEM in the BASIC DIAGNOSTIC PROCEDURES article. If fuel pressure is OK, go to next step. If fuel pressure is not OK, do the following: If fuel pressure is to high, replace fuel pressure regulator. Go to step 18. If fuel pressure is to low, check fuel pump, fuel feed pipe and fuel filter. If they are OK, replace fuel pressure regulator. Go to step 18. NOTE: Fuel pump, fuel pressure regulator and fuel filter are all part of the Fuel Tank Unit and are in fuel tank.
16. Turn ignition off.
17. Turn ignition off. Remove VTEC oil pressure switch. Install Adapter (07NAJ-P07010A), Hose (07MAJ-PY40120) and Gauge (07406-0070300). (Scheme 26) Reinstall VTEC oil pressure switch. Reconnect VTEC solenoid valve single pin harness connector and VTEC oil pressure switch 2-pin harness connector. Start engine and run at 3000 RPM with no load (A/T in Park or Neutral) until radiator fan comes on. Connect remote tachometer under hood. Check oil pressure at 1000 and 2000 RPM. Checks should be done in under one minute because of engine running with no load. If oil pressure is less than 49 kPa, check for air in fuel line. Go to next step. If oil pressure is not as specified, inspect VTEC system oil line. Go to next step.
18. Turn ignition on.
19. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu.
20. With the Honda PGM tester or the HDS, do the CKP PATTERN CLEAR in the CLEAR menu.
21. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
22. Do the CKP pulse learn procedure. See «CKP PATTERN LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__ckp-pattern-learn-procedure).
23. Test drive vehicle for several minutes in the range of the recorded freeze frames.
24. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0301, P0302, P0303, P0304, P0305 or P0306 are set, check for poor connections or loose terminals at ignition coils, fuel injectors and PCM harness connectors. Go to «DTC P0301, DTC P0302, DTC P0303, DTC P0304, DTC P0305 OR DTC P0306»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__dtc-p0301-dtc-p0302-dtc-p0303). If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, go to next step.
25. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0301, P0302, P0303, P0304, P0305 or P0306 in the DTCs menu. If it is PASSED, troubleshooting is complete. If it FAILED. Go to step 1. If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION, go to step 23 and recheck.

DTC P0301, DTC P0302, DTC P0303, DTC P0304, DTC P0305 OR DTC P0306

Code Definition

1. DTC P0301: Cylinder No. 1 Misfire Detected
2. DTC P0302: Cylinder No. 2 Misfire Detected
3. DTC P0303: Cylinder No. 3 Misfire Detected
4. DTC P0304: Cylinder No. 4 Misfire Detected
5. DTC P0305: Cylinder No. 5 Misfire Detected
6. DTC P0306: Cylinder No. 6 Misfire Detected

1. Note the following freeze frame data: Engine Speed Vehicle Speed Throttle Position CLV Gear Position
2. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
3. Start engine with no load (A/T in Park or Neutral), then let it idle.
4. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P0301, P0302, P0303, P0304, P0305 or P0306 in the DTC menu. If it is PASSED, go to next step. If it FAILED. Go to step 9. If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION, wait for several minutes and recheck.
5. Using the Honda PGM Tester or the HDS, check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE in the DATA list for 10 minutes. If it does show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, go to step 9. If it does not show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, go to next step.
6. Test drive vehicle for several minutes in the range of the recorded freeze frames.
7. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0301, P0302, P0303, P0304, P0305 or P0306 in the DTCs menu. If it is PASSED, go to next step. If it FAILED. Go to step 9. If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION, go to step 6 and recheck.
8. Using the Honda PGM Tester or the HDS, check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE in the DATA list for 10 minutes. If it does show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, go to next step. If it does not show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, problem is intermittent, system is OK at this time.
9. Turn ignition off.
10. Remove intake manifold cover.
11. Start engine and listen for clicking sound at fuel injector on suspect cylinder. If injector clicks, go to next step. If injector does not click, go to step 19.
12. Turn ignition off. Exchange ignition coil from suspect cylinder with one from another cylinder. Test drive vehicle several times in range of recorded freeze data.
13. Using the Honda PGM Tester or the HDS, check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE in the DATA list for 10 minutes. If it does show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, go to next step. If it does not show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, problem is intermittent, misfire due to poor contact at ignition coil connector (no misfire at this time). Make sure coil connections are secure.
14. Determine which cylinder had misfire. If misfire followed ignition coil that was exchanged, replace ignition coil. Go to step 30. If misfire stayed in same cylinder, go to next step.
15. Turn ignition switch off. Exchange spark plug from suspect cylinder with one from another cylinder.
16. Test drive vehicle several times in range of recorded freeze data.
17. Using the Honda PGM Tester or the HDS, check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE in the DATA list for 10 minutes. If it does show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, go to next step. If it does not show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, problem is intermittent, misfire due to spark plug fouling (no misfire at this time).
18. Determine which cylinder had misfire. If misfire followed spark plug that was exchanged, replace spark plug. Go to step 30. If misfire stayed in same cylinder, go to next step.
19. Turn ignition switch off. Exchange fuel injector from suspect cylinder with one from another cylinder. Test drive vehicle several times in range of recorded freeze data.
20. Using the Honda PGM Tester or the HDS, check the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE in the DATA list for 10 minutes. If it does show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, go to next step. If it does not show the CYL1 MISFIRE, CYL2 MISFIRE, CYL3 MISFIRE, CYL4 MISFIRE, CYL5 MISFIRE and/or CYL6 MISFIRE misfire counts, problem is intermittent, misfire due to poor contact at fuel injector connector (no misfire at this time). Make sure fuel injector connections are secure.
21. Determine which cylinder had misfire. If misfire followed injector that was exchanged, replace injector. Go to step 30. If misfire stayed in same cylinder, go to next step.
22. Turn ignition switch off. Disconnect suspect ignition coil 3-pin harness connector. (Scheme 8)
23. Turn ignition on. Measure voltage between ground and ignition coil 3-pin harness connector terminal No. 3 (Black/White wire). If there is battery voltage, go to next step. If there is not battery voltage, repair open in wire between ignition coil and ignition coil relay. Go to step 30.
24. Turn ignition off. Check for continuity between ground and ignition coil 3-pin harness connector terminal No. 2 (Black wire). If there is continuity, go to next step. If there is no continuity, repair open in wire between ignition coil and ground connectors G101 and G102. Go to step 30.
25. Disconnect PCM harness connector "A". (Scheme 4) Check for continuity between ground and PCM harness connector terminal. See «DTC/PCM "A" HARNESS CONNECTOR TERMINAL IDENTIFICATION»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics). If continuity is present, repair short in wire between PCM harness connector "A" and ignition coil 3-pin harness connector. Go to step 30. If no continuity is present, go to next step. DTC/PCM "A" HARNESS CONNECTOR TERMINAL IDENTIFICATION Suspect Cylinder DTC PCM Terminal No. Wire Color No. 1 P0301 A33 Yellow/Green No. 2 P0302 A34 Blue/Red No. 3 P0303 A35 White/Blue No. 4 P0304 A36 Brown No. 5 P0305 A37 Black/Red No. 6 P0306 A38 Brown/White
26. Reconnect PCM harness connector. Connect fused jumper wire between ground and suspect ignition coil 3-pin harness connector terminal No. 1. (Scheme 8) Check for continuity between ground and PCM harness connector terminal. See «DTC/PCM "A" HARNESS CONNECTOR TERMINAL IDENTIFICATION»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics). If continuity is present, go to next step. If continuity is not present, repair open wire between PCM harness connector "A" and ignition coil 3-pin harness connector terminal No. 1. See appropriate wiring diagram under ENGINE PERFORMANCE in WIRING DIAGRAMS. Repair as necessary. Go to step 30.
27. Reconnect ignition coil 3-pin harness connector. Reconnect PCM harness connector "A".
28. Do an engine compression and cylinder leakdown test. If the engine passes both tests, go to next step. If the engine does not pass both tests, repair engine. Go to step 30.
29. Do the VTEC rocker arm test. See «VTEC ROCKER ARM TEST»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__vtec-rocker-arm-test). If engine passes test, go to step 37. If the engine did not pass test repair VTEC rocker arm. Go to next step.
30. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Go to next step.
31. With the Honda PGM tester or the HDS, do the CKP PATTERN CLEAR in the CLEAR menu.
32. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
33. Do the CKP pulse learn procedure. See «CKP PATTERN LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__ckp-pattern-learn-procedure).
34. Test drive vehicle for several minutes in the range of the recorded freeze frames.
35. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0301, P0302, P0303, P0304, P0305 or P0306 are set, check for poor connections or loose terminals at ignition coils, fuel injectors and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, go to next step.
36. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0301, P0302, P0303, P0304, P0305 or P0306 in the DTCs menu. If it is PASSED, troubleshooting is complete. If it FAILED. Go to step 1 and recheck. If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION, go to step 34 and recheck.
37. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
38. Test drive vehicle for several minutes in the range of the recorded freeze frames.
39. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0301, P0302, P0303, P0304, P0305 or P0306 are set, check for poor connections or loose terminals at ignition coils, fuel injectors and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

Scheme 8

DTC P0325: KNOCK SENSOR CIRCUIT MALFUNCTION

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold at 3000 RPM with no load (A/T in Park or Neutral) until radiator fan comes on, then let it idle.
3. Hold engine at 3000-4000 RPM for at least 60 seconds.
4. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0325 is set, go to next step. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTC P0340 is not set, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at knock sensor and PCM connectors.
5. Turn ignition switch off. Disconnect PCM harness connector "A". (Scheme 4) Disconnect KS sub-harness 1-pin connector. Check for continuity between ground and PCM harness connector terminal A26 (Red/Blue wire). (Scheme 4) If continuity is present, repair short in Red/Blue wire between PCM harness connector and KS sub-harness connector. Go to step 11. If continuity is not present, go to next step.
6. Connect fused jumper wire between ground and KS sub-harness 1-pin connector. Check for continuity in Red/Blue wire between ground and PCM harness connector terminal A26 (Red/Blue wire). If continuity is present, go to next step. If continuity is not present, repair open in Red/Blue wire between PCM harness connector and KS sub-harness connector. Go to step 8.
7. Remove intake manifold.
8. Check KS sub-harness 1-pin connector and knock sensor for an open or short. If they are OK, go to next step. If they are not OK, repair or replace KS sub-harness. Go to step 11.
9. Replace knock sensor.
10. Install intake manifold.
11. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
12. Start engine. Hold at 3000 RPM with no load (A/T in Park or Neutral) until radiator fan comes on, then let it idle.
13. Hold engine at 3000-4000 RPM for at least 60 seconds.
14. Check for Temporary DTCs or DTCs in the DTC menu. If any Temporary DTCs or DTCs are set, go to step 16. If any Temporary DTCs or DTCs are not set, go to next step.
15. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0325 in the DTCs menu. If it is PASSED, troubleshooting is complete. If it FAILED, go to step 1. If it is NOT COMPLETED, go to step 12 and recheck.
16. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
17. Start engine. Hold at 3000 RPM with no load (A/T in Park or Neutral) until radiator fan comes on, then let it idle.
18. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0325 is set, check for poor connections or loose terminals at knock sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P0335 OR DTC P0385

Code Definition

1. DTC P0335: Crankshaft Position Sensor "A" No Signal
2. DTC P0385: Crankshaft Position Sensor "B" No Signal

Note. This test covers both "A" and "B" CKP sensors circuit malfunctions. The information will be shown "A" first and "B" second. When discussion arises, "A" sensors and circuit terminals will precede "B" sensors and circuit terminals. Furthermore, "B" sensors and circuit terminals information will be enclosed in parantheses ( ).

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0335 or P0385 are set, go to next step. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTCs P0335 or P0385 are not set, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at CKP sensors "A" and "B" and PCM connectors.
3. Turn ignition switch off. Disconnect CKP sensor A/B 6-pin harness connector. (Scheme 9) Turn ignition on. Measure voltage between ground and CKP sensor "A/B" 6-pin connector terminals No. 6 (No. 3). If battery voltage is present, go to next step. If battery voltage is not present, repair open in wire between CKP sensor A/B connector terminals No. 6 (No. 3) and PGM-FI main relay 1. Go to step 10.
4. Measure voltage between ground and CKP sensor A/B 6-pin connector terminal No. 5 (No. 2). If 5 volts is present, go to next step. If 5 volts is not present, go to step 6.
5. Measure voltage between CKP sensor A/B 6-pin connector terminals No. 4 (No. 1) and No. 6 (No. 3). If battery voltage is present, go to step 8. If battery voltage is not present, repair open in wire between CKP sensor A/B and ground connector G101. Go to step 10.
6. Turn ignition off. Disconnect PCM harness connector "A". (Scheme 4) Check for continuity between PCM harness connector terminals A44 (A46) and CKP sensor A/B 6-pin connector terminals No.5 (No.2). If there is continuity, go to next step. If there is no continuity, repair open in wire between PCM harness connector terminals A44 (A46) and CKP sensor. Go to step 10.
7. Check for continuity between ground and PCM harness connector terminals A44 (A46). If there is continuity, repair short in wire between PCM harness connector terminals A44 (A46) and CKP sensor Go to step 10. If there is no continuity, go to step 15.
8. Turn ignition off.
9. Replace CKP sensor A/B.
10. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Go to next step.
11. With the Honda PGM tester or the HDS, do the CKP PATTERN CLEAR in the CLEAR menu.
12. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
13. Do the CKP pulse learn procedure. See «CKP PATTERN LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__ckp-pattern-learn-procedure).
14. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0335 or P0385 are set check for poor connections or loose terminals at CKP sensor A/B and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.
15. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
16. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0335 or P0385 are set, check for poor connections or loose terminals at CMP sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

Scheme 9

DTC P0339 OR DTC P0389

Code Definition

1. DTC P0339: Crankshaft Position Sensor "A" Intermittent Interruption
2. DTC P0389: Crankshaft Position Sensor "B" Intermittent Interruption

Note. This test covers both "A" and "B" CKP sensors circuit malfunctions. The information will be shown "A" first and "B" second. When discussion arises, "A" sensors and circuit terminals will precede "B" sensors and circuit terminals. Furthermore, "B" sensors and circuit terminals information will be enclosed in parantheses ( ).

1. Note the following freeze data. Engine speed. Vehicle speed.
2. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
3. Start engine and let idle for 10 seconds.
4. Using Honda PGM Tester or the HDS, check for CKP NOISE 1 or (2) COUNT in the DATA list. If 0 counts are indicated, go to next step. If 0 counts are not indicated, go to step 8 .
5. Test drive vehicle for several minutes in the range of the recorded freeze frame data.
6. Using Honda PGM Tester or the HDS, check for CKP NOISE 1 or (2) COUNT in the DATA list. If 0 counts are indicated, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at CKP sensor A/B and PCM harness connectors. If 0 counts are not indicated, go to next step.
7. Check for poor connections or loose terminals at the following locations: CKP sensor A/B. PCM. Engine ground. Body ground. If connections and terminals are OK, go to next step. If connections and terminals are not OK, repair connections and terminals. Go to step 11 .
8. Check for damage on the CKP sensor A/B pulse plate. If it is damaged, replace the CKP sensor A/B pulse plate. Go to step 11 . If it is OK, go to next step.
9. Turn ignition off.
10. Replace the CKP sensor A/B.
11. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Go to next step.
12. With the Honda PGM tester or the HDS, do the CKP PATTERN CLEAR in the CLEAR menu. Go to next step.
13. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Go to next step.
14. Do the CKP pulse learn procedure. See «CKP PATTERN LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__ckp-pattern-learn-procedure) .
15. Start engine and let idle for 10 seconds.
16. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0339 or P0389 are set check for poor connections or loose terminals at CKP sensor A/B and PCM harness connector. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.

DTC P0340: CAMSHAFT POSITION SENSOR NO SIGNAL

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0340 is set, go to next step. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTC P0340 is not set, check for poor connections or loose terminals at CMP sensor and PCM connectors.
3. Turn ignition off. Disconnect CMP sensor 3-pin connector. see scheme 10 Go to next step.
4. Measure voltage between ground and CMP sensor 3-pin connector terminal No. 3 (Yellow/Black wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open in wire between CMP sensor and PGM-FI main relay 1 (FI MAIN). Go to step 12.
5. Measure voltage between ground and CMP sensor 3-pin connector terminal No. 1 (Yellow wire). If about 5 volts are present, go to next step. If about 5 volts are not present, go to step 7.
6. Measure voltage between CMP sensor 3-pin connector terminals No. 2 (Brown/Yellow wire) and No. 3 (Yellow/Black wire). If battery voltage is present, go to step 12. If battery voltage is not present, repair open in wire between CMP sensor and ground connector G101. Go to step 12.
7. Turn ignition off. Go to next step.
8. Disconnect PCM harness connector "A". (Scheme 4) Check for continuity between CMP sensor 3-pin connector terminal No. 1 and PCM harness connector terminal A45 (Yellow wire). If there is continuity, go to next step. If there is no continuity, repair short in wire between PCM and CMP sensor. Go to step 12.
9. Check for continuity between ground and CMP sensor 3-pin connector terminal No. 1 (Yellow wire). If there is continuity, repair short in wire between PCM and CMP sensor. Go to step 12. If there is no continuity, go to step 14.
10. Turn ignition off.
11. Replace CMP sensor.
12. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
13. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0340 is set, check for poor connections or loose terminals at CMP sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.
14. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
15. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0340 is set, check for poor connections or loose terminals at CMP sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P0344: CAMSHAFT POSITION SENSOR INTERMITTENT INTERRUPTION

1. Note the following freeze data: Engine Speed Vehicle Speed
2. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
3. Start engine and let idle for 10 seconds.
4. Using Honda PGM Tester or the HDS, check for CMP NOISE 2 COUNT in the DATA list. If 0 counts are indicated, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at CMP sensor and PCM harness connectors. If 0 counts are not indicated, go to next step.
5. Check for poor connections or loose terminals at the following locations: CMP Sensor PCM Engine Ground Body Ground If connections and terminals are OK, go to next step. If connections and terminals are not OK, repair connections and terminals. Go to step 9 .
6. Check for damage on the front camshaft pulley (CMP sensor pulse plate). If it is damaged, replace the front camshaft pulley (CMP sensor pulse plate). If it is OK, go to next step.
7. Turn ignition off. Go to next step.
8. Replace CMP sensor. Go to next step.
9. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Go to next step.
10. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0344 is set, check for poor connections or loose terminals at CMP sensor and PCM harness connector. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.

DTC P0401: EGR SYSTEM INSUFFICIENT FLOW DETECTED

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold at 3000 RPM with no load (A/T in Park or Neutral) until radiator fan comes on, then let it idle.
3. Using Honda PGM Tester or the HDS, do the EGR TEST in the INSPECTION menu. If the EGR system is OK, go to next step. If the EGR system is not OK, go to step 6 .
4. Test drive under the following conditions: Engine coolant temperature more than 158°F (70°C). A/T in "D" position. Vehicle speed at 30 MPH or more and engine speed between 1100 and 2300 RPM. During drive, decelerate (with throttle fully closed) for 5 seconds.
5. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0401 in the DTCs menu. If it is PASSED, problem is intermittent system is OK at this time. If it FAILED, remove EGR valve and EGR plate. Clean the intake manifold EGR port with carburetor cleaner. Also clean the passage inside EGR valve with carburetor cleaner. Install EGR valve and EGR plate. Go to step 8 . If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION , go to step 4 and recheck.
6. Turn ignition off.
7. Replace EGR valve.
8. Turn ignition on.
9. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Go to next step.
10. Test drive under the following conditions: Engine coolant temperature more than 158°F (70°C). A/T in "D" position. Vehicle speed at 30 MPH or more and engine speed between 1100 and 2300 RPM. During drive, decelerate (with throttle fully closed) for 5 seconds.
11. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0401 is set, check for poor connections or loose terminals at EGR valve and PCM connectors. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTC P0401 is not set, go to next step.
12. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0401 in the DTCs menu. If it is PASSED, troubleshooting is done. If it is FAILED, go to step 1 and recheck. If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION , go to step 10 and recheck.

DTC P0403: EGR CONTROL CIRCUIT MALFUNCTION

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle.
3. With the Honda PGM tester or the HDS, do the EGR test in the INSPECTION menu. If the EGR system is OK, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at EGR valve and PCM connectors. If EGR system is not OK, go to next step.
4. Turn ignition off. Disconnect EGR 6-pin connector. (Scheme 25) At the EGR valve side, measure resistance between connector terminals No. 4 and 6. If there is about 6.3-6.7 ohms, go to next step. If there is not about 6.3-6.7 ohms, go to step 8.
5. Disconnect PCM harness connector "A". (Scheme 4) Check for continuity between ground and PCM harness connector terminal A15 (Blue/Red wire). If there is continuity, repair short in wire between PCM harness connector terminal A15 and EGR valve. Go to step 9. If there is no continuity, go to next step.
6. With a fused jumper wire, connect EGR connector terminal No. 4 to ground. Check for continuity between ground and PCM harness connector terminal A15 (Blue/Red wire). If there is continuity, go to next step. If there is no continuity, repair open in wire between PCM harness connector terminal A15 and EGR valve. Go to step 9.
7. Check for continuity between ground and EGR 6-pin harness connector terminal No. 6 (Black wire). If there is continuity, update the PCM if it does not have the latest software, or substitute a known-good PCM. Go to step 9. If there is no continuity, repair open in wire between ground and EGR 6-pin harness connector terminal No. 6. Go to step 9.
8. Replace EGR valve.
9. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
10. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle.
11. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0403 is set, check for poor connections or loose terminals at EGR valve and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P0404: EGR CONTROL CIRCUIT RANGE/PERFORMANCE PROBLEM

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle.
3. With the Honda PGM tester or the HDS, do the EGR test in the INSPECTION menu. If the EGR system is OK, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at EGR valve and PCM connectors. If EGR system is not OK, go to next step.
4. Turn ignition off. Disconnect EGR 6-pin connector. (Scheme 25) At the EGR valve sensor side, measure resistance between connector terminals No. 1 and 2. If there is about 100K ohms, go to step 17. If there is not about 6.3-6.7 ohms, go to next step.
5. At the sensor side, measure resistance between EGR valve 6-pin connector terminal No. 1 and 3. If there is resistance of 100K ohms or more, go to step 17. If there is no resistance, go to next step.
6. Check continuity between ground and EGR valve 6-pin connector terminal No. 6 (Black wire). If there is continuity, go to next step. If there is no continuity, repair open in wire between EGR valve 6-pin connector terminal No. 6 (Black wire) and ground connector G101. Go to step 18.
7. Disconnect PCM harness connector "A". (Scheme 4) Check for continuity between ground and PCM harness connector terminal A15 (Blue/Red wire). If there is continuity, repair short in wire between PCM harness connector terminal A15 and EGR valve 6-pin connector terminal No. 4 (Blue/Red wire). Go to step 18. If there is no continuity, go to next step.
8. Check for continuity between PCM harness connector terminal A15 and EGR valve 6-pin connector terminal No. 4 (Blue/Red wire). If there is continuity, go to next step. If there is no continuity, repair open in wire between PCM harness connector terminal A15 and EGR valve 6-pin connector terminal No. 4 (Blue/Red wire). Go to step 17.
9. Remove EGR valve and EGR plate.
10. Clean the intake manifold EGR port with carburetor cleaner. Also clean the passage inside EGR valve with carburetor cleaner. Install EGR valve and EGR plate.
11. Reconnect EGR valve 6-pin connector. Reconnect PCM harness connector "A".
12. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
13. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle.
14. With the Honda PGM tester or the HDS, do the EGR test in the INSPECTION menu. If the EGR system is OK, go to step 20. If EGR system is not OK, go to next step.
15. Turn ignition off.
16. Replace EGR valve.
17. Turn ignition on.
18. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
19. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle.
20. Test drive vehicle under light load for about 10 minutes. Try to keep engine speed in the 1700-2500 RPM range.
21. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0404 is set, check for poor connections or loose terminals at EGR valve and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, go to next step.
22. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0404 in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED. Go to step 1 and recheck. If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION, go to step 20 and recheck.

DTC P0406: EGR VALVE POSITION SENSOR CIRCUIT, HIGH VOLTAGE

1. Turn ignition on. With the Honda PGM tester or the HDS, check the EGR VLS in the DATA list. If there is about 4.88 volts, go to next step. If there is not about 4.88 volts, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at EGR valve and PCM harness connectors.
2. Turn ignition off. Disconnect EGR 6-pin connector. (Scheme 25) go to next step.
3. Turn ignition on. Measure voltage between EGR valve 6-pin connector terminal No. 2 (Green/Yellow wire) and 3 (Yellow/Blue wire). If there is about 5 volts, go to step 5. If there is not about 5 volt, go to next step.
4. Turn ignition off. Disconnect PCM harness connector "A". (Scheme 4) Check for continuity between PCM harness connector terminal A28 and EGR 6-pin connector terminal No. 2 (Green/Yellow wire). If there is continuity, go to step 9. If there is no continuity, repair open in wire between PCM harness connector terminal A28 and EGR 6-pin connector terminal No. 2 (Green/Yellow wire)
5. Turn off ignition.
6. Replace EGR valve.
7. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
8. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0406 is set, check for poor connections or loose terminals at EGR valve and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.
9. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
10. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0406 is set, check for poor connections or loose terminals at EGR valve and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P0420 OR DTC P0430

Code Definition

1. DTC P0420: Rear Bank Catalyst System Efficiency Below Threshold (Bank 1)
2. DTC P0430: Front Bank Catalyst System Efficiency Below Threshold (Bank 2)

Note. This test covers both "REAR" and "FRONT" bank catalytic converter malfunctions. The information will be shown "REAR" first and "FRONT" second. When discussion arises, "REAR" bank catalytic converter will precede "FRONT" bank catalytic converter. Furthermore "FRONT" bank catalytic converter information will be enclosed in parantheses ( ).

Note. If DTCs P0137, P0138, P0141, P0161, P0157, or P0158 are set, troubleshoot these codes before proceeding.

Note. When poor fuel quality is used, this DTC may be set.

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold at 3000 RPM with no load (A/T in Park or Neutral) until radiator fan comes on, then let it idle.
3. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). A/T in "D" position. Vehicle speed between 50-55 MPH with cruise control. Drive about 2 minutes, then decelerate for at least 4 seconds with throttle completely closed, then accelerate to 55 MPH for 20 minutes with cruise control.
4. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0420 and/or (P0430) in the DTCs menu. If it is EXECUTING, continue driving condition until a result comes in. If it is not EXECUTING, go to step 3 and recheck.
5. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0420 and/or (P0430) in the DTCs menu. If it is PASSED, problem is intermittent, system is OK at this time. If it FAILED, go to next step. If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION, go to step 4 and recheck.
6. Turn ignition off.
7. Replace the WU-TWC.
8. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Go to next step.
9. Start engine. Hold at 3000 RPM with no load (A/T in Park or Neutral) until radiator fan comes on, then let it idle.
10. Test drive vehicle for about 10 minutes, changing vehicle speeds frequently.
11. With the Honda PGM tester or the HDS, check the CAT MON TEMP in the DATA list. If it is OK, go to next step. If it is not OK, go to step 9 and recheck.
12. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). A/T in "D" position. Vehicle speed between 50-55 MPH with cruise control. Drive about 2 minutes, then decelerate for at least 4 seconds with throttle completely closed, then accelerate to 55 MPH for 20 minutes with cruise control.
13. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0420 and/or (P0430) in the DTCs menu. If it is EXECUTING, continue driving condition until a result comes in. If it is not EXECUTING, go to step 12 and recheck.
14. Check for Temporary DTCs or DTCs in the DTC menu. If Temporary DTCs or DTCs are set, go to indicated DTC and troubleshoot. If Temporary DTCs or DTCs are not set, go to next step.
15. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0420 and/or (P0430) in the DTCs menu. If it is PASSED, troubleshooting is done. If it is FAILED, check the fuel quality. If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION, go to step 12 and recheck.

DTC P0443: EVAP CANISTER PURGE VALVE CIRCUIT MALFUNCTION

Note. Special tools required: Vacuum Pump/Gauge, 0-30 in.Hg (A973X-041-XXXXX) Vacuum/Pressure Gauge, 0-4 in.Hg (07JAZ-001000B)

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0443 is set, go to next step. If DTC P0443 is not set, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at EVAP canister purge valve and PCM connectors.
3. Turn ignition off.
4. Disconnect vacuum hose (A) from EVAP canister purge valve (B) and connect a vacuum pump/gauge to the hose. (Scheme 16)
5. Start engine and let it idle. The ECT SENSOR in the DATA list must be below 131°F (56°C). If there is vacuum, go to next step. If there is no vacuum, go to step 8.
6. Turn ignition off. Disconnect EVAP canister purge valve 2-pin connector. Check for continuity between ground and EVAP canister purge valve 2-pin connector terminal No. 1 (Red/Yellow wire). If there is continuity, go to next step. If there is no continuity, go to step 13.
7. Turn ignition off. Disconnect PCM harness connector "A". (Scheme 4) Check for continuity between ground and EVAP canister purge valve 2-pin connector terminal No. 1 (Red/Yellow wire). If there is continuity, repair short in wire between EVAP canister purge valve 2-pin connector terminal No. 1 and PCM harness connector terminal A16. If there is no continuity, go to step 18.
8. Turn ignition off. Disconnect EVAP canister purge valve 2-pin connector.
9. Turn ignition on. Measure voltage between ground and EVAP canister purge valve 2-pin connector terminal No. 2 (White/Black wire). If there is battery voltage, go to next step. If there is no battery voltage, repair open in wire between EVAP canister purge valve 2-pin connector terminal No. 2 an No. 9 LAF HT (15-amp) fuse in under-hood sub-fuse box. Go to step 14.
10. Turn ignition off. Disconnect PCM harness connector "A". Check for continuity between PCM harness connector terminal A16 (Red/Yellow wire) and EVAP canister purge valve 2-pin connector terminal No. 1. If there is continuity, go to next step. If there is no continuity, repair open in wire between EVAP canister purge valve 2-pin connector terminal No. 1 PCM harness connector terminal A16.
11. Measure resistance between EVAP canister purge valve 2-pin connector terminal No. 1. and 2. If there is about 23 ohms at room temperature, go to step 18. If there is not about 23 ohms at room temperature, go to next step.
12. Replace EVAP canister purge valve.
13. Reconnect PCM harness connector "A".
14. Reconnect EVAP canister purge valve.
15. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
16. Start engine. Hold at 3000 RPM with no load (A/T in Park or Neutral) until radiator fan comes on, then let it idle.
17. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0443 is set, check for poor connections or loose terminals at EVAP canister vent shut valve and PCM connectors. Go to step 1. If DTC P0443 is not set, troubleshooting is done.
18. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
19. Start engine. Hold at 3000 RPM with no load (A/T in Park or Neutral) until radiator fan comes on, then let it idle.
20. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0443, check for poor connections or loose terminals at EVAP canister purge valve and PCM connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P0451: FUEL TANK PRESSURE SENSOR CIRCUIT, RANGE/PERFORMANCE PROBLEM

Note. If DTC P2422 is stored at the same time as DTC P0451, troubleshoot DTC P2422 first, then recheck for DTC P0451.

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine and let idle for 1 minute.
3. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0451 in the DTCs menu. If it is PASSED, problem is intermittent system is OK at this time. If it FAILED, go to next step. and recheck. If it is NOT COMPLETED, go to step 2 and recheck.
4. Turn ignition off.
5. Replace FTP sensor.
6. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Go to next step.
7. Start engine, let idle for 1 minute. Using Honda PGM Tester or the HDS, check for Temporary DTCs or DTCs in the DTC menu. If DTC P0451 is set, check for poor connections or loose terminals at FTP sensor and PCM connectors. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, go to next step.
8. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0451 in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED, check for poor connections or loose terminals at FTP sensor and PCM connectors. Go to step 1 . If it is NOT COMPLETED, go to step 7 and recheck.

DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT, LOW VOLTAGE

Note. If DTC P0651 is stored at the same time as DTC P0452, troubleshoot DTC P0651 first, then recheck for DTC P0452.

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Turn ignition off. Remove fuel fill cap and wait 1 minute. Turn ignition on. Using Honda PGM Tester or the HDS, check the FTP SENSOR in the DATA list. If there is about 7.3 kPa (2.16 in.Hg) or 0.3 volt or less, go to step 4. If there is more or less than 7.3 kPa (2.16 in.Hg) or 0.3 volt or less, go to next step.
3. Install fuel fill cap. Start engine. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0452 in the DTCs menu. If it is PASSED, problem is intermittent, system is OK at this time. If it FAILED, go to next step. If it is NOT COMPLETED, repeat this step and recheck.
4. Turn ignition off. Disconnect FTP sensor 3-pin connector. (Scheme 10) Turn ignition on. Using Honda PGM Tester or the HDS, check the FTP SENSOR in the DATA list. If there is about 7.3 kPa (2.16 in.Hg) or 4.7 volts, go to next step. If there is more or less than about 7.3 kPa (2.16 in.Hg) or 4.7 volts, go to step 8.
5. Measure voltage between ground and FTP sensor connector terminal No 1 (Yellow/Blue wire). If there is about 5 volts, go to step 7. If there is not about 5 volts, go to next step.
6. Turn ignition off. Disconnect PCM harness connector "B". (Scheme 4) With a fused jumper wire, connect FTP sensor connector terminal No. 1 to ground. Check for continuity between ground and PCM harness connector terminal B46 (Yellow/Blue wire). If there is continuity, go to step 13. If there is no continuity, repair open in wire between PCM harness connector terminal B46 and FTP sensor connector terminal No. 1. Go to step 9.
7. Turn ignition off. Disconnect PCM harness connector "B". Check for continuity between ground and FTP sensor connector terminal No. 3 (Light Green wire). If there is continuity, repair short in wire between PCM harness connector terminal B47 and FTP sensor connector terminal No. 3. If there is no continuity, go to step 13.
8. Turn ignition off. Replace FTP sensor.
9. Reconnect PCM harness connector "B". Reconnect FTP sensor 3-pin connector. Turn ignition on.
10. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Go to next step.
11. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Using Honda PGM Tester or the HDS, check for Temporary DTCs or DTCs in the DTC menu. If DTC P0452 is set, check for poor connections or loose terminals at FTP sensor and PCM connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, go to next step.
12. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0452 in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED, check for poor connections or loose terminals at FTP sensor and PCM connector. Go to step 1 and recheck. If it is NOT COMPLETED, go to step 11 and recheck.
13. Update the PCM if it does not have the latest software, or substitute a know-good PCM.
14. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Using Honda PGM Tester or the HDS, check for Temporary DTCs or DTCs in the DTC menu. If DTC P0452 is set, check for poor connections or loose terminals at FTP sensor and PCM connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

Scheme 10

DTC P0453: FUEL TANK PRESSURE SENSOR CIRCUIT, HIGH VOLTAGE

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Turn ignition off. Remove fuel fill cap and wait 1 minute. Turn ignition on. Using Honda PGM Tester or the HDS, check the FTP SENSOR in the DATA list. If there is about 7.3 kPa (2.16 in.Hg) or 4.7 volts or more, go to step 4. If there is more or less than 7.3 kPa (2.16 in.Hg) or 4.7 volts or more, go to next step.
3. Install fuel fill cap. Start engine. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0452 in the DTCs menu. If it is PASSED, problem is intermittent, system is OK at this time. If it FAILED, go to next step. If it is NOT COMPLETED, repeat this step and recheck.
4. Turn ignition off. Disconnect FTP sensor 3-pin connector. (Scheme 10) Turn ignition on. Measure voltage between ground and FTP sensor connector terminal No 3 (Light Green wire). If there is about 5 volts, go to next step. If there is not about 5 volts, go to step 6.
5. Measure voltage between FTP sensor connector terminal No 1 (Yellow/Blue wire) terminal No. 2 (Green/Black wire). If there is about 5 volts, go to step 7. If there is not about 5 volts, go to step 8.
6. Turn ignition off. Disconnect PCM harness connector "B". (Scheme 4) With a fused jumper wire, connect FTP sensor connector terminal No. 3 to ground. Check for continuity between ground and PCM harness connector terminal B47 (Light Green wire). If there is continuity, go to step 12. If there is no continuity, repair open in wire between PCM harness connector terminal B47 and FTP sensor connector terminal No. 3. Go to step 8.
7. Turn ignition off. Replace FTP sensor.
8. Reconnect PCM harness connector "B". Reconnect FTP sensor 3-pin connector. Turn ignition on.
9. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Go to next step.
10. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Using Honda PGM Tester or the HDS, check for Temporary DTCs or DTCs in the DTC menu. If DTC P0453 is set, check for poor connections or loose terminals at FTP sensor and PCM connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, go to next step.
11. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0453 in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED, check for poor connections or loose terminals at FTP sensor and PCM connector. Go to step 1 and recheck. If it is NOT COMPLETED, go to step 10 and recheck.
12. Update the PCM if it does not have the latest software, or substitute a know-good PCM.
13. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Using Honda PGM Tester or the HDS, check for Temporary DTCs or DTCs in the DTC menu. If DTC P0453 is set, check for poor connections or loose terminals at FTP sensor and PCM connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P0455: EVAPORATIVE EMISSION CONTROL SYSTEM, VERY LARGE LEAK DETECTED

Note. Special tools required: Vacuum Pump/Gauge, 0-30 in.Hg (A973X-041-XXXXX) Vacuum/Pressure Gauge, 0-4 in.Hg (07JAZ-001000B)

1. Inspect fuel filler cap, seal and filler neck seal surface. Cap must be tightened at least three clicks to seal system. Replace if necessary. If fuel filler cap and fuel fill pipe is okay, go to next step.
2. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu. Turn ignition off.
3. Using Honda PGM Tester or the HDS, do the EVAP FUNCTION test in the INSPECTION menu. NOTE: If the EVAP FUNCTION test is stopped, start engine and let idle for 15 minutes, then test again. If there is not enough vapor in the fuel tank, do the PCS leak check. See «DTC P0497: EVAP SYSTEM LOW PURGE FLOW»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__dtc-p0497-evap-system-low-purge) for PCS leak check procedure. If EVAP SYSTEM is NORMAL, problem is intermittent, system is OK at this time. Check for poor connections and loose terminals at FTP sensor, EVAP bypass solenoid valve, EVAP canister purge valve, or EVAP canister vent shut valve and PCM connectors. If EVAP SYSTEM is not NORMAL, go to next step.
4. Go to the appropriate step based on testers display: If "Small Leak is Detected in Canister" is displayed, go to step 5. If "Small Leak is Detected in Tank" is displayed, go to step 22. If another result is displayed, go to step 28.
5. Turn ignition off. Disconnect 2 vapor hoses (A) from EVAP 2-way valve (B). Plug tank port side (C) of the EVAP 2-way valve. Connect a T-fitting (D) from the vacuum gauge and the vacuum pump to the EVAP 2-way valve. See (a) in (Scheme 11).
6. Turn ignition on. Using Honda PGM Tester or the HDS, do the EVAP BPS ON test in the INSPECTION menu.
7. Slowly apply 0.4 in.Hg of vacuum to hose.
8. If it holds vacuum for about 20 seconds, go to next step. If it does not hold vacuum for about 20 seconds, replace EVAP 2-way valve or "O" ring. Go to step 46.
9. Reconnect fuel tank side vapor hose (A) to the 2-way bypass valve (B). Plug canister side vapor/vacuum hose (C). See (b) in (Scheme 11).
10. Check the connection of the fuel tank vapor control valve vent hose and quick connect fitting. If the hose is connected properly, go to next step. If the hose is not connected properly, repair the fuel tank vapor control valve vent hose and quick connect fitting. Go to step 46.
11. Disconnect fuel tank vapor control valve vent hose (A) from EVAP canister (B) and plug canister port (C). See (c) in (Scheme 11).
12. Disconnect vacuum hose (A) between EVAP canister and EVAP canister purge valve (B) from EVAP canister purge valve side. Connect T-fitting (C) from vacuum gauge and vacuum pump to vacuum hose (A). See (a) in (Scheme 12).
13. Slowly apply 0.6 in.Hg of vacuum to hose.
14. If it holds vacuum for about 1 minute, inspect fuel tank vapor control valve vent hose. If OK replace fuel tank. Go to step 46. If it does not hold vacuum for about 1 minute, go to next step.
15. Disconnect all drain hoses from EVAP canister vent shut valve and plug their ports.
16. Slowly apply 0.6 in.Hg of vacuum to hose. If it holds vacuum for about 1 minute, replace EVAP canister vent shut valve. Go to step 46. If it does not hold vacuum for about 1 minute, go to next step.
17. Disconnect vacuum hose (A) between EVAP canister (B) and EVAP canister vent shut valve from EVAP canister side, plug EVAP canister port (C). See (b) in (Scheme 12).
18. Slowly apply 0.6 in.Hg of vacuum to hose. If it holds vacuum for about 1 minute, check hose between EVAP canister vent shut valve and EVAP canister. If hose is OK, replace EVAP canister vent shut valve. Go to step. Go to step 46. If it does not hold vacuum for about 1 minute, go to next step.
19. Reconnect vacuum hose to EVAP canister purge valve.
20. Disconnect vacuum hose (A) between EVAP canister (B) and EVAP canister purge valve from EVAP canister side. Connect T-fitting (C) from vacuum gauge and vacuum pump to vacuum hose (A). See (a) in (Scheme 13).
21. Slowly apply 0.6 in.Hg of vacuum to hose. If it holds vacuum, check for damage to EVAP canister. If EVAP canister is OK, go to step 46. If it does not hold vacuum, check hose between EVAP canister purge valve and EVAP canister. If hose is OK, replace EVAP canister purge valve. Go to step 46.
22. Turn ignition off. Disconnect 2 vapor hoses (A) from EVAP 2-way valve (B). Plug tank port side (C) of the EVAP 2-way valve. Connect a T-fitting (D) from the vacuum gauge and the vacuum pump to the EVAP 2-way valve. See (b) in (Scheme 13).
23. Turn ignition on. Using Honda PGM Tester or the HDS, do the EVAP BPS ON test in the INSPECTION menu.
24. Slowly apply 0.4 in.Hg of vacuum to hose.
25. If it holds vacuum for about 20 seconds, go to next step. If it does not hold vacuum for about 20 seconds replace EVAP 2-way valve or "O" ring. Go to step 46.
26. Test fuel tank vapor control valve. See «FUEL TANK VAPOR CONTROL VALVE TEST»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics) article. If fuel tank vapor control valve is OK, go to next step. If fuel tank vapor control valve is not OK, then replace fuel tank vapor control valve. Go to step 28.
27. Check for poor connections at fuel tank vapor tube, fuel tank vapor recirculation tube, fuel tank vapor signal tube, FTP sensor hoses and vapor line between EVAP 2-way valve and fuel tank. If all lines are OK, remove fuel pump and check mating seal surfaces and seal. If all connections are not OK, reconnect or replace the loose hose/tube. Go to step 46 Reconnect fuel tank.
28. Turn ignition off. Reconnect fuel tank side vapor hose (A) to the 2-way bypass valve (B). Plug canister side vapor/vacuum hose (C). See (b) in (Scheme 11).
29. Check the connection of the fuel tank vapor control valve vent hose and quick connect fitting. If the hose is connected properly, go to next step. If the hose is not connected properly, replace the fuel tank vapor control valve vent hose and quick connect fitting. Go to step 46.
30. Disconnect fuel tank vapor control valve vent hose (A) from EVAP canister (B) and plug canister port (C). See (c) in (Scheme 11).
31. Disconnect vacuum hose (A) between EVAP canister and EVAP canister purge valve (B) from EVAP canister purge valve side. Connect T-fitting (C) from vacuum gauge and vacuum pump to vacuum hose (A). See (a) in (Scheme 12).
32. Slowly apply 0.6 in.Hg of vacuum to hose.
33. If it holds vacuum for about 1 minute, inspect fuel tank vapor control valve vent hose. If OK replace fuel tank vapor control valve. Go to step 46. If it does not hold vacuum for about 1 minute, go to next step.
34. Disconnect all drain hoses from EVAP canister vent shut valve.
35. Slowly apply 0.6 in.Hg of vacuum to hose. If it holds vacuum for about 1 minute, replace EVAP canister vent shut valve. Go to step 46. If it does not hold vacuum for about 1 minute, go to next step.
36. Disconnect vacuum hose (A) between EVAP canister (B) and EVAP canister vent shut valve from EVAP canister side, plug EVAP canister port (C). See (b) in (Scheme 12).
37. Slowly apply 0.6 in.Hg of vacuum to hose. If it holds vacuum for about 1 minute, check hose between EVAP canister vent shut valve and EVAP canister. If hose is OK, replace EVAP canister vent shut valve. Go to step. Go to step 46. If it does not hold vacuum for about 1 minute, go to next step.
38. Reconnect vacuum hose to EVAP canister purge valve.
39. Disconnect vacuum hose (A) between EVAP canister (B) and EVAP canister purge valve from EVAP canister side. Connect T-fitting (C) from vacuum gauge and vacuum pump to vacuum hose (A). See (a) in (Scheme 13).
40. Slowly apply 0.6 in.Hg of vacuum to hose. If it holds vacuum, check for damage to EVAP canister. If EVAP canister is OK, go to next step. If it does not hold vacuum, check hose between EVAP canister purge valve and EVAP canister. If hose is OK, replace EVAP canister purge valve. Go to step 46.
41. Turn ignition off. Disconnect 2 vapor hoses (A) from EVAP 2-way valve (B). Plug tank port side (C) of the EVAP 2-way valve. Connect a T-fitting (D) from the vacuum gauge and the vacuum pump to the EVAP 2-way valve. See (b) in (Scheme 13).
42. Turn ignition on. Using Honda PGM Tester or the HDS, do the EVAP BPS ON test in the INSPECTION menu.
43. Slowly apply 0.4 in.Hg of vacuum to hose. If it holds vacuum for about 20 seconds, go to next step. If it does not hold vacuum for about 20 seconds replace EVAP 2-way valve or "O" ring. Go to step 46.
44. Test fuel tank vapor control valve. See «FUEL TANK VAPOR CONTROL VALVE TEST»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics) article. If fuel tank vapor control valve is OK, go to next step. If fuel tank vapor control valve is not OK, then replace fuel tank vapor control valve. Go to step 28.
45. Check for poor connections at fuel tank vapor tube, fuel tank vapor recirculation tube, fuel tank vapor signal tube, FTP sensor hoses and vapor line between EVAP 2-way valve and fuel tank. If all lines are OK, remove fuel pump and check mating seal surfaces and seal. If all connections are not OK, reconnect or replace the loose hose/tube. Go to step 46.
46. Reconnect all hoses and connectors.
47. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
48. Using Honda PGM Tester or the HDS, do the EVAP FUNCTION test in the INSPECTION menu.
49. If EVAP SYSTEM is NORMAL, troubleshooting is complete. If EVAP SYSTEM is not NORMAL, check for poor connections and loose terminals at FTP sensor, EVAP bypass solenoid valve, EVAP canister purge valve, or EVAP canister vent shut valve and PCM connectors. Go to step 1.

Scheme 11

Scheme 12

Scheme 13

DTC P0456: EVAPORATIVE EMISSION CONTROL SYSTEM, VERY SMALL LEAK DETECTED

Note. Special tools required: Vacuum Pump/Gauge, 0-30 in.Hg (A973X-041-XXXXX) Vacuum/Pressure Gauge, 0-4 in.Hg (07JAZ-001000B)

1. Inspect fuel filler cap, seal and filler neck seal surface. Cap must be tightened at least three clicks to seal system. Replace if necessary. If fuel filler cap and fuel fill pipe is okay, go to next step.
2. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu. Turn ignition off.
3. Using Honda PGM Tester or the HDS, do the EVAP FUNCTION test in the INSPECTION menu.
4. If EVAP SYSTEM is NORMAL, problem is intermittent, system is OK at this time. Check for poor connections and loose terminals at FTP sensor, EVAP bypass solenoid valve, EVAP canister purge valve, or EVAP canister vent shut valve and PCM connectors. If EVAP SYSTEM is not NORMAL, go to next step.
5. Go to the appropriate step based on testers display. If "Small Leak is Detected in Canister" is displayed, go to step 6. If "Small Leak is Detected in Tank" is displayed, go to step 23.
6. Turn ignition off. Disconnect 2 vapor hoses (A) from EVAP 2-way valve (B). Plug tank port side (C) of the EVAP 2-way valve. Connect a T-fitting (D) from the vacuum gauge and the vacuum pump to the EVAP 2-way valve. See (b) in (Scheme 13).
7. Turn ignition on. Using Honda PGM Tester or the HDS, do the EVAP BPS ON test in the INSPECTION menu.
8. Slowly apply 0.4 in.Hg of vacuum to hose.
9. If it holds vacuum for about 20 seconds, go to next step. If it does not hold vacuum for about 20 seconds replace EVAP 2-way valve or "O" ring. Go to step 28.
10. Turn ignition off. Reconnect fuel tank side vapor hose (A) to the 2-way bypass valve (B). Plug canister side vapor/vacuum hose (C). See (b) in (Scheme 11).
11. Check the connection of the fuel tank vapor control valve vent hose and quick connect fitting. If the hose is connected properly, go to next step. If the hose is not connected properly, replace the fuel tank vapor control valve vent hose and quick connect fitting. Go to step 28.
12. Disconnect fuel tank vapor control valve vent hose (A) from EVAP canister (B) and plug canister port (C). See (c) in (Scheme 11).
13. Disconnect vacuum hose (A) between EVAP canister and EVAP canister purge valve (B) from EVAP canister purge valve side. Connect T-fitting (C) from vacuum gauge and vacuum pump to vacuum hose (A). See (a) in (Scheme 12).
14. Slowly apply 0.6 in.Hg of vacuum to hose.
15. If it holds vacuum for about 1 minute, inspect fuel tank vapor control valve vent hose. If OK replace fuel tank vapor control valve. Go to step 28. If it does not hold vacuum for about 1 minute, go to next step.
16. Disconnect all drain hoses from EVAP canister vent shut valve.
17. Slowly apply 0.6 in.Hg of vacuum to hose. If it holds vacuum for about 1 minute, replace EVAP canister vent shut valve. Go to step 28. If it does not hold vacuum for about 1 minute, go to next step.
18. Disconnect vacuum hose (A) between EVAP canister (B) and EVAP canister vent shut valve from EVAP canister side, plug EVAP canister port (C). See (b) in (Scheme 12).
19. Slowly apply 0.6 in.Hg of vacuum to hose. If it holds vacuum for about 1 minute, check hose between EVAP canister vent shut valve and EVAP canister. If hose is OK, replace EVAP canister vent shut valve. Go to step. Go to step 28. If it does not hold vacuum for about 1 minute, go to next step.
20. Reconnect vacuum hose to EVAP canister purge valve.
21. Disconnect vacuum hose (A) between EVAP canister (B) and EVAP canister purge valve from EVAP canister side. Connect T-fitting (C) from vacuum gauge and vacuum pump to vacuum hose (A). See (a) in (Scheme 13).
22. Slowly apply 0.6 in.Hg of vacuum to hose. If it holds vacuum, check for damage to EVAP canister. If EVAP canister is OK, go to next step. If it does not hold vacuum, check hose between EVAP canister purge valve and EVAP canister. If hose is OK, replace EVAP canister purge valve. Go to step 28.
23. Turn ignition off. Disconnect 2 vapor hoses (A) from EVAP 2-way valve (B). Plug tank port side (C) of the EVAP 2-way valve. Connect a T-fitting (D) from the vacuum gauge and the vacuum pump to the EVAP 2-way valve. See (b) in (Scheme 13).
24. Turn ignition on. Using Honda PGM Tester or the HDS, do the EVAP BPS ON test in the INSPECTION menu.
25. Slowly apply 0.4 in.Hg of vacuum to hose. If it holds vacuum for about 20 seconds, go to next step. If it does not hold vacuum for about 20 seconds replace EVAP 2-way valve or "O" ring. Go to step 28.
26. Test fuel tank vapor control valve. See «FUEL TANK VAPOR CONTROL VALVE TEST»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics) article. If fuel tank vapor control valve is OK, go to next step. If fuel tank vapor control valve is not OK, then replace fuel tank vapor control valve. Go to step 28
27. Check for poor connections at fuel tank vapor tube, fuel tank vapor recirculation tube, fuel tank vapor signal tube, FTP sensor hoses and vapor line between EVAP 2-way valve and fuel tank. If all lines are OK, remove fuel pump and check mating seal surfaces and seal. Go to next step. If all connections are not OK, reconnect or replace the loose hose/tube. Go to step 29.
28. Reconnect all hoses and connectors.
29. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See PCM Idle Learn Procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
30. Using Honda PGM Tester or the HDS, do the EVAP FUNCTION test in the INSPECTION menu.
31. If EVAP SYSTEM is NORMAL, troubleshooting is complete. If EVAP SYSTEM is not NORMAL, check for poor connections and loose terminals at FTP sensor, EVAP bypass solenoid valve, EVAP canister purge valve, or EVAP canister vent shut valve and PCM connectors. Go to step 1.

DTC P0457: EVAPORATIVE EMISSION CONTROL SYSTEM LEAK DETECTED, FUEL FILL CAP LOOSE/OFF

1. Inspect fuel filler cap, seal and filler neck seal surface. Cap must be tightened at least three clicks to seal system. Replace if necessary. If fuel filler cap and fuel fill pipe is okay, go to next step.
2. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu. Turn ignition off.
3. Using Honda PGM Tester or the HDS, do the EVAP FUNCTION test in the INSPECTION menu.
4. If EVAP SYSTEM is NORMAL, problem is intermittent, system is OK at this time. Check for poor connections and loose terminals at FTP sensor, EVAP bypass solenoid valve, EVAP canister purge valve, or EVAP canister vent shut valve and PCM connectors. If EVAP SYSTEM is not NORMAL, go to next step.
5. Turn ignition off. Remove EVAP canister vent shut valve. Connect 2-pin connector to EVAP canister vent shut valve.
6. Turn ignition on. Using Honda PGM Tester or the HDS, do the EVAP CVS ON test in the INSPECTION menu. Check EVAP canister vent shut valve operation. If the valve operates, find and correct a pinch in EVAP canister vent tube. Go to step 11 . If the valve does not operate, go to next step.
7. Turn ignition off. Replace EVAP canister vent shut valve.
8. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Go to next step.
9. Using Honda PGM Tester or the HDS, do the EVAP FUNCTION test in the INSPECTION menu.
10. If EVAP SYSTEM is NORMAL, troubleshooting is complete. If EVAP SYSTEM is not NORMAL, check for poor connections and loose terminals at FTP sensor, EVAP bypass solenoid valve, EVAP canister purge valve, or EVAP canister vent shut valve and PCM connectors. Go to step 1 .
11. Reinstall EVAP canister vent shut valve.
12. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Go to next step.
13. Using Honda PGM Tester or the HDS, do the EVAP FUNCTION test in the INSPECTION menu.
14. If EVAP SYSTEM is NORMAL, troubleshooting is complete. If EVAP SYSTEM is not NORMAL, check for poor connections and loose terminals at FTP sensor, EVAP bypass solenoid valve, EVAP canister purge valve, or EVAP canister vent shut valve and PCM connectors. Go to step 1 .

DTC P0461: FUEL LEVEL SENSOR RANGE/PERFORMANCE

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0461 is set, go to next step. If DTC P0461 is not set, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at fuel gauge sending unit and PCM connectors.
3. Turn ignition off. Remove driver's side second row seat. Cut the carpet, (be careful not to cut wire harness). Remove the access panel from the floor. Disconnect fuel pump 5-pin connector. Remove fuel fill cap. Relieve fuel pressure. See MDX under «FUEL SYSTEM PRESSURE RELEASE»(ref-151684-S08147627932003010600000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. Disconnect the quick-connect fittings from the fuel tank unit. Using Wrench (07XAA-001010A), loosen fuel tank unit lock nut (A). (Scheme 14) Remove fuel tank unit. Go to next step.
4. Test fuel gauge sending unit. Turn ignition on. With fuel pump 5-pin connector disconnected, measure voltage between fuel pump 5-pin connector terminals No. 1 (Black wire) and 2 (Yellow/Blue wire). If there is between 5-8 volts, go to next step. If there is not between 5-8 volts, repair open in Black or Yellow/Blue wire. Or repair poor ground at connector G501.
5. Turn ignition off. Install a 2 ohm resistor between fuel pump 5-pin connector terminals No. 1 (Black wire) and 2 (Yellow/Blue wire). Go to next step.
6. Turn ignition on. If the fuel gauge pointer indicates "F", gauge is OK, go to next step. If the fuel gauge pointer does not indicate "F", replace gauge.
7. Turn ignition off. Measure resistance between fuel tank unit terminals No. 1 and 2, with the float at E (empty), L (low), 1/2 (half full) and F (full) positions. (Scheme 15) If you do not obtain the following readings, replace fuel gauge sending unit. See «FUEL GAUGE SENDING UNIT SPECIFICATIONS»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics). If sending unit checks OK, check for poor connections or loose terminals at fuel gauge sending unit and PCM connectors. Go to step 8.
8. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
9. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0461 is set, check for poor connections or loose terminals at PCM and fuel gauge sending unit. Go to step 1. If any other Temporary DTCs or DTCs are set, go to the indicated DTC and troubleshoot. If DTC P0461 is not set, troubleshooting is done.

FUEL GAUGE SENDING UNIT SPECIFICATIONS

Scheme 14

Scheme 15

DTC P0462: FUEL LEVEL SENSOR CIRCUIT, LOW VOLTAGE

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Using Honda PGM Tester or the HDS, check FUEL LVL SENSOR in the DATA list. If the measured value is 0.05 volt or less, go to next step. If the measured value is not 0.05 volt or less, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at fuel level sensor, the gauge unit and PCM connectors.
3. Turn ignition off. Disconnect fuel pump 5-pin connector.
4. Turn ignition on. Using Honda PGM Tester or the HDS, check FUEL LVL SENSOR in the DATA list. If the measured value is 0.05 volt or less, go to next step. If the measured value is not 0.05 volt or less, go to step 9.
5. Disconnect PCM harness connector "B". (Scheme 4) Disconnect gauge assembly connector "A". (Scheme 21) Check continuity between ground and PCM harness connector terminal B49 (Yellow/Blue wire). If there is continuity, repair short in wire between PCM, gauge assembly and fuel level sensor. Go to step 11. If there is no continuity, go to next step.
6. Check continuity between PCM harness connector terminal B49 (Yellow/Blue wire) and gauge assembly connector terminal No. 2. If there is continuity, go to next step. If there is no continuity, repair open in wire between PCM harness connector terminal B49 (Yellow/Blue wire) and gauge assembly connector terminal No. 2. Go to step 11.
7. Reconnect PCM harness connector "B". Reconnect gauge assembly connector.
8. Turn ignition on. Measure voltage between ground and gauge assembly connector "A" terminal No. 2 (Yellow/Blue wire). If there is battery voltage, go to step 13. If there is not battery voltage, replace gauge assembly. Go to step 11.
9. Turn ignition off.
10. Replace fuel gauge sending unit.
11. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
12. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0462 is set, check for poor connections or loose terminals at fuel level sensor and PCM connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, go to the indicated DTC troubleshooting. If no Temporary DTCs or DTCs are set, troubleshooting is done.
13. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
14. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0462 is set, check for poor connections or loose terminals at fuel level sensor and PCM connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, go to the indicated DTC troubleshooting. If DTC P0462 is not set and PCM was updated troubleshooting is done. If PCM was substituted, replace original PCM.

DTC P0463: FUEL LEVEL SENSOR CIRCUIT, HIGH VOLTAGE

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Turn ignition on. Using Honda PGM Tester or the HDS, check FUEL LVL SENSOR in the DATA list. If the measured value is 4.95 volts or more, go to next step. If the measured value is not 4.95 volts or more, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at fuel gauge sending unit, gauge assembly and PCM connectors.
3. Turn ignition off. Remove driver's side second row seat. Cut the carpet, (be careful not to cut wire harness). Remove the access panel from the floor. Disconnect fuel pump 5-pin connector. Go to next step.
4. Measure resistance between fuel pump 5-pin connector terminals No. 1 and 2. If resistance is 130 ohms or more, replace fuel gauge sending unit. If resistance is not 130 ohms or more, go to next step.
5. Check for continuity between ground and fuel pump 5-pin connector terminals No. 1 (Yellow/Blue wire). If there is continuity, repair short in wire between PCM harness connector terminal B49 and fuel gauge sending unit. Go to step 7. If there is no continuity, go to next step.
6. Disconnect gauge assembly connector "A". (Scheme 21) Check for continuity between fuel pump 5-pin connector terminals No. 1 and gauge assembly connector "A" terminal No. 4 (Black wire). If there is continuity, replace gauge assembly. Go to next step. If there is no continuity, repair open in wire between fuel pump 5-pin connector terminals No. 1 and gauge assembly connector "A" terminal No. 4. Go to next step.
7. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
8. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0463 is set, check for poor connections or loose terminals at gauge assembly and PCM connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, go to the indicated DTC troubleshooting. If no Temporary DTCs or DTCs are set, troubleshooting is done.

DTC P0496: EVAP CANISTER SYSTEM HIGH PURGE FLOW

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Using Honda PGM Tester or the HDS, do the EVAP FUNCTION test in the INSPECTION menu.
3. If EVAP SYSTEM is NORMAL, problem is intermittent, system is OK at this time. Check for poor connections and loose terminals at FTP sensor, EVAP bypass solenoid valve, EVAP canister purge valve, or EVAP canister vent shut valve and PCM connectors. If EVAP SYSTEM is not NORMAL, go to next step.
4. Replace EVAP canister purge valve located by throttle body.
5. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Go to next step.
6. Using Honda PGM Tester or the HDS, do the EVAP FUNCTION test in the INSPECTION menu.
7. If EVAP SYSTEM is NORMAL, troubleshooting is complete. If EVAP SYSTEM is not NORMAL, check for poor connections and loose terminals at FTP sensor, EVAP bypass solenoid valve, EVAP canister purge valve, or EVAP canister vent shut valve and PCM connectors. Go to step 1 .

DTC P0497: EVAP SYSTEM LOW PURGE FLOW

Note. Special tools required: Vacuum Pump/Gauge, 0-30 in.Hg (A973X-041-XXXXX) Vacuum/Pressure Gauge, 0-4 in.Hg (07JAZ-001000B)

1. Inspect fuel filler cap, seal and filler neck seal surface. Cap must be tightened at least three clicks to seal system. Replace if necessary. If fuel filler cap and fuel fill pipe is okay, go to next step.
2. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu. Turn ignition off.
3. Using Honda PGM Tester or the HDS, do the EVAP FUNCTION test in the INSPECTION menu.
4. If EVAP SYSTEM is NORMAL, problem is intermittent, system is OK at this time. Check for poor connections and loose terminals at FTP sensor, EVAP bypass solenoid valve, EVAP canister purge valve, or EVAP canister vent shut valve and PCM connectors. If EVAP SYSTEM is not NORMAL, go to next step.
5. Check for looseness or damage on PCS line between intake manifold and EVAP canister purge valve. If line is OK, go to next step. If line is not OK, reconnect or repair PCS line. Go to step 21.
6. Disconnect PCS hose at purge joint (A) and connect vacuum pump to the hose (B). (Scheme 16) Connect a T-fitting (C) from vacuum gauge and vacuum pump to the PCS hose (A).
7. Turn ignition on. Using Honda PGM Tester or the HDS, do the EVAP PCS OFF in the INSPECTION menu.
8. Slowly apply 0.6 in.Hg of vacuum to hose. If it holds vacuum, go to next step. If it does not hold vacuum, check for looseness or damage between EVAP canister purge valve and EVAP canister. Go to step 21.
9. Turn ignition on. Using Honda PGM Tester or the HDS, do the EVAP PCS ON in the INSPECTION menu.
10. If the vacuum changes to atmospheric pressure, go to next step. If the vacuum does not change to atmospheric pressure, check for clogged PCS line between EVAP canister purge valve and EVAP canister. Go to step 21.
11. Disconnect vacuum hose (A) from FTP sensor (B). (Scheme 16) Disconnect vacuum hose (A) between EVAP canister (B) and EVAP 2-way valve (C) at EVAP canister side. Connect a T-fitting (D) from vacuum gauge and vacuum pump to the PCS hose (A).
12. Slowly apply 0.6 in.Hg of vacuum to hose. If it holds vacuum, go to next step. I fit does not hold vacuum, Reconnect or repair vacuum hose between EVAP canister and EVAP 2-way valve. Go to step 21.
13. Turn ignition on. Using Honda PGM Tester or the HDS, do the EVAP PCS ON in the INSPECTION menu.
14. If the vacuum changes to atmospheric pressure, go to next step. If the vacuum does not change to atmospheric pressure, check for clogged vacuum hose between EVAP canister and EVAP 2-way valve and between EVAP 2-way valve and FTP sensor. If vacuum hoses are OK, replace EVAP 2-way valve. Go to step 21.
15. Connect a vacuum pump to hose disconnected from FTP sensor. Slowly apply 0.6 in.Hg of vacuum to hose. If it holds vacuum, go to next step. If it does not hold vacuum, reconnect or repair vacuum hose between EVAP 2-way valve and FTP sensor. Go to step 21.
16. Connect a T-fitting (A) from vacuum gauge and vacuum pump to FTP sensor (Scheme 17) Slowly apply 0.4 in.Hg of vacuum to FTP sensor. Go to next step.
17. Turn ignition on. Using Honda PGM Tester or the HDS, check the FTP SENSOR in the DATA list. If the difference is 1.1 kPa (0.31 in.Hg) or more, go to next step. If the difference is 1.1 kPa (0.31 in.Hg) or less, replace FTP sensor. Go to step 21 Disconnect vacuum hose (A) to EVAP 2-way valve (B) at the EVAP canister (C) side and plug the EVAP canister port (D). (Scheme 17) Disconnect PCS hose (E) from EVAP canister (C). Connect T-fitting (F) from vacuum gauge and vacuum pump to PCS hose (E).
18. Turn ignition on. Using Honda PGM Tester or the HDS, do the EVAP PCS OFF in the INSPECTION menu.
19. Using Honda PGM Tester or the HDS, do the EVAP PCS ON in the INSPECTION menu.
20. Slowly apply 0.6 in.Hg of vacuum to hose. If it holds vacuum, check for a clogged EVAP canister port. Go to next step. If it does not hold vacuum, replace the EVAP canister vent shut valve.
21. Turn ignition on.
22. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
23. Using Honda PGM Tester or the HDS, do the EVAP FUNCTION test in the INSPECTION menu.
24. If EVAP SYSTEM is NORMAL, troubleshooting is complete. If EVAP SYSTEM is not NORMAL, reconnect or repair fuel tank vapor control vent tube and hose between EVAP vent shut valve and EVAP canister. If hoses and tubes are OK, check for poor connections and loose terminals at FTP sensor, EVAP bypass solenoid valve, EVAP canister purge valve, or EVAP canister vent shut valve and PCM connectors. Go to step 1.

Scheme 16

Scheme 17

DTC P0498: EVAP CANISTER VENT SHUT VALVE CONTROL CIRCUIT, LOW VOLTAGE

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Using Honda PGM Tester or the HDS, do the EVAP CVS CLOSE in the INSPECTION menu. Wait 5 seconds.
3. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0498 is set, go to step 6. If DTC P0498 is not set, go to next step.
4. Using Honda PGM Tester or the HDS, do the EVAP CVS CLOSE in the INSPECTION menu. Wait 5 seconds.
5. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0498 is set, go to next step. If DTC P0498 is not set, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at EVAP canister vent shut valve and PCM connectors.
6. Turn ignition off. Disconnect EVAP canister vent shut valve 2-pin connector.
7. Check for continuity between ground and EVAP canister vent shut valve 2-pin connector terminal No. 1 (Green/Black wire). If there is continuity, go to next step. If there is no continuity, go to step 9.
8. Disconnect PCM harness connector "B". (Scheme 4) Check for continuity between ground and EVAP canister vent shut valve 2-pin connector terminal No. 1 (Green/Black wire). If there is continuity, repair short in wire between EVAP canister vent shut valve 2-pin connector terminal No. 1 (Green/Black wire) and PCM harness connector terminal B8. Go to step 13. If there is no continuity, go to next step.
9. Turn ignition on. Measure voltage between ground and EVAP canister vent shut valve 2-pin connector terminal No. 2 (White/Black wire). If there is battery voltage, go to next step. If there is not battery voltage, repair open in wire between EVAP canister vent shut valve and No. 18 ACG (15-amp) fuse in under-dash fuse/relay box. Go to step 13.
10. Turn ignition off. With a fused jumper wire, connect EVAP canister vent shut valve 2-pin connector terminal No. 1 to ground. Check for continuity between ground and PCM harness connector terminal B8. If there is continuity, go to next step. If there is no continuity, repair open in wire between EVAP canister vent shut valve 2-pin connector terminal No. 1 (Green/Black wire) and PCM harness connector terminal B8. Go to step 13.
11. Measure resistance between EVAP canister vent shut valve 2-pin connector terminal No. 1 and 2. If there is about 25-30 ohms at room temperature, go to step 17. If there is not about 25-30 ohms at room temperature, go to next step.
12. Replace EVAP canister vent shut valve.
13. Reconnect PCM harness connector "B".
14. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
15. Using Honda PGM Tester or the HDS, do the EVAP CVS CLOSE in the INSPECTION menu. Wait 5 seconds.
16. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0498 is set, check for poor connections or loose terminals at EVAP canister vent shut valve and PCM connectors. Go to step 1. If DTC P0498 is not set, troubleshooting is done.
17. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
18. Using Honda PGM Tester or the HDS, do the EVAP CVS CLOSE in the INSPECTION menu. Wait 5 seconds.
19. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1498, check for poor connections or loose terminals at EVAP canister vent shut valve and PCM connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P0499: EVAP CANISTER VENT SHUT VALVE CONTROL CIRCUIT, HIGH VOLTAGE

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Using Honda PGM Tester or the HDS, do the EVAP CVS CLOSE in the INSPECTION menu. Wait 5 seconds.
3. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0499 is set, update the PCM if it does not have the latest software, or substitute a known-good PCM. Then recheck. If symptom goes away with a known-good PCM, replace original PCM. If DTC P0499 is not set, problem is intermittent, system is OK at this time.

DTC P0506: IDLE CONTROL SYSTEM RPM LOWER THAN EXPECTED

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes.
3. Test under the following conditions: Engine coolant temperature more than 156°F (70°C). Intake air temperature more than 32°F (0°C). More than 15 seconds elapsed after stating engine. Vehicle not moving. Fuel trim between 0.73 and 1.47. Fuel feedback in closed loop.
4. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0506 in the DTCs menu. If it is FAILED, go to next step. If it PASSED, go to step 12. If it is EXECUTING, keep the condition continual until a result comes in. If it is OUT OF CONDITION, go to step 3 and recheck.
5. Remove intake air duct from throttle body. Check for dirt, carbon and damage at throttle bore. If there is dirt or carbon at throttle bore remove throttle body for cleaning. Be careful not to pinch fingers. (Scheme 23) Wipe off carbon deposits on throttle valve and inside throttle bore with a paper towel soaked in carburetor cleaner. Install throttle body. Go to step 7. If there is damage in throttle bore, go to next step. If there is no dirt, carbon and damage at throttle bore, check A/C system, power steering system. Go to step 1 and recheck.
6. Replace throttle body, go to next step.
7. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
8. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes.
9. Test under the following conditions: Engine coolant temperature more than 156°F (70°C). Intake air temperature more than 32°F (0°C). More than 15 seconds elapsed after stating engine. Vehicle not moving. Fuel trim between 0.73 and 1.47. Fuel feedback in closed loop.
10. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0506 is set, go to 1 and recheck. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, go to next step.
11. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0506 in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED, go to step 1. f it is EXECUTING, keep the condition continual until a result comes in. If it is OUT OF CONDITION, go to step 9 and recheck.
12. Remove intake air duct from throttle body. Check for dirt, carbon and damage at throttle bore. If there is dirt or carbon at throttle bore remove throttle body for cleaning. Be careful not to pinch fingers. (Scheme 23) Wipe off carbon deposits on throttle valve and inside throttle bore with a paper towel soaked in carburetor cleaner. Install throttle body. Go to step 7. If there is damage in throttle bore, go to step 6. If there is no dirt, carbon and damage at throttle bore, go to next step.
13. Recheck with different load conditions. Turn on headlights, blower motor, rear window defogger and/or A/C, changing gear positions, etc.
14. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0506 in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED, check A/C system, power steering system. Go to 1 and recheck. If it is EXECUTING, keep the condition continual until a result comes in. If it is OUT OF CONDITION, go to step 13 and recheck.

DTC P0507: IDLE CONTROL SYSTEM RPM HIGHER THAN EXPECTED

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes.
3. Test under the following conditions: Engine coolant temperature more than 156°F (70°C). Intake air temperature more than 32°F (0°C). More than 15 seconds elapsed after stating engine. Vehicle not moving. Fuel trim between 0.73 and 1.47. Fuel feedback in closed loop.
4. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0507 in the DTCs menu. If it is FAILED, check for vacuum leaks, go to next step. If it PASSED, problem is intermittent, system is OK at this time. If it is EXECUTING, keep the condition continual until a result comes in. If it is OUT OF CONDITION, go to step 3 and recheck.
5. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Go to next step.
6. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes.
7. Test under the following conditions: Engine coolant temperature more than 156°F (70°C). Intake air temperature more than 32°F (0°C). More than 15 seconds elapsed after stating engine. Vehicle not moving. Fuel trim between 0.73 and 1.47. Fuel feedback in closed loop.
8. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0507 is set, go to 1 and recheck. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, go to next step.
9. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0507 in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED, go to step 1 and recheck. f it is EXECUTING, keep the condition continual until a result comes in. If it is OUT OF CONDITION, go to step 7 and recheck.

DTC P0563: PCM POWER SOURCE CIRCUIT, UNEXPECTED VOLTAGE

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Turn ignition off. Wait 10 seconds.
3. Turn ignition on.
4. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0563 is set, go to next step. If DTC P0563 is not set, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at No. 6 FI-ECU (PCM (15-amp) fuse in the driver's under dash fuse/relay box and at PCM connectors.
5. Turn ignition off. Disconnect PCM harness connector "B". (Scheme 4) Go to next step.
6. Measure voltage between ground and PCM harness connector terminal B12 (Yellow/Green wire). If there is battery voltage, go to step 9. If there is no battery voltage, go to next step.
7. Remove driver's dashboard lower cover, then remove PGM-FI main relay 1 (FI Main).
8. Check for continuity between ground and PCM harness connector terminal B12 (Yellow/Green wire). If there is continuity, repair short in wire between PCM harness connector terminal B12 (Yellow/Green wire) and PGM-FI main relay 1 (FI Main). Go to step 15. If there is no continuity, go to step 14.
9. Reconnect PCM harness connector "B".
10. Measure voltage between ground and PGM-FI main relay 1 (FI Main) 4-pin connector No. 3. If there is battery voltage, go to next step. If there is no battery voltage, go to step 19.
11. Disconnect PCM harness connector "A". Measure voltage between ground and PCM harness connector terminal A18 (Yellow/Black wire). If there is battery voltage, go to next step. If there is no battery voltage, go to step 19.
12. Remove driver's dashboard lower cover, then remove PGM-FI main relay 1 (FI Main).
13. Measure voltage between ground and PCM harness connector terminal A18 (Yellow/Black wire). If there is battery voltage, repair short to power between PCM harness connector terminal A18 (Yellow/Black wire) and the PGM-FI main relay 1 (FI Main). Go to step 16. If there is no battery voltage, go to next step.
14. Replace PGM-FI main relay 1 (FI Main).
15. Turn ignition on.
16. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
17. Turn ignition off. Wait for 10 seconds.
18. Turn ignition on. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0563 is set, check for poor connections or loose terminals at PGM-FI main relay 1 (FI Main) and at PCM connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTC P0563 is not set, troubleshooting is done.
19. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
20. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0563 are set, check for poor connections or loose terminals at the PCM and the PGM-FI main relay 1 (FI Main) connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, go to the indicated DTC and troubleshoot. If DTC P0563 are not set, PCM was updated, troubleshooting is done. If PCM was substituted, replace original PCM.

DTC P0603: PCM INTERNAL CONTROL MODULE KEEP ALIVE MEMORY ERROR

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Wait 1 second.
3. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0603 is set, update the PCM if it does not have the latest software, or substitute a known-good PCM. If the problem goes away with a known-good PCM, replace PCM. If DTC P0603 is not set, problem is intermittent, system is OK at this time.

DTC P0606: PCM PROCESSOR MALFUNCTION

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Turn ignition off.
3. Turn ignition on.
4. Wait 40 second.
5. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0606 is set, update the PCM if it does not have the latest software, or substitute a known-good PCM. If the problem goes away with a known-good PCM, replace PCM. If DTC P0606 is not set, problem is intermittent, system is OK at this time.

DTC P0627: PGM-FI MAIN RELAY 2 CIRCUIT MALFUNCTION (FUEL PUMP)

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Turn ignition on. Wait for 10 seconds.
3. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0627 is set, go to step 6. If DTC P0606 is not set, go to next step.
4. Crank engine for 5 seconds.
5. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0627 is set, go to next step. If DTC P0627 is not set, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at PGM-FI main relay 2 (Fuel Pump) and PCM connectors.
6. Turn ignition off. Disconnect PCM harness connector "B". (Scheme 4)
7. Remove PGM-FI main relay 2 (Fuel Pump).
8. Check for continuity between PCM harness connector terminal B13 and PGM-FI main relay 2 (Fuel Pump) connector terminal No. 5 (Green/Yellow wire). If there is continuity, go to next step. If there is no continuity, repair open in wire between PCM harness connector terminal B13 and PGM-FI main relay 2 (Fuel Pump) connector terminal No. 5. Go to step 15.
9. Check for continuity between ground and PGM-FI main relay 2 (Fuel Pump) connector terminal No. 3. If there is continuity, go to next step. If there is no continuity, repair open in wire between PCM and PGM-FI main relay 2 (Fuel Pump) connector terminal No. 3 or repair poor ground at ground connector G401. Go to step 15.
10. Check for continuity between ground and PGM-FI main relay 2 (Fuel Pump) connector terminal No. 5 (Green/Yellow wire). If there is continuity, repair short in wire between PCM harness connector terminal B13 and PGM-FI main relay 2 (Fuel Pump) connector terminal No. 5. If there is no continuity, go to next step.
11. Substitute a known-good PGM-FI relay 2 (Fuel Pump).
12. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Go to next step.
13. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
14. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0627 are set, go to step 19. If DTC P0627 is not set, replace original relay. Go to next step.
15. Turn ignition on.
16. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Go to next step.
17. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
18. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0627 are set, check for poor connections or loose terminals at the PCM and the PGM-FI main relay 2 (Fuel Pump) connector. Go to step 1. If any other Temporary DTCs or DTCs are set, go to the indicated DTC and troubleshoot. If DTC P0627 are not set, troubleshooting is done.
19. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
20. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0627 are set, check for poor connections or loose terminals at the PCM and the PGM-FI main relay 2 (Fuel Pump) connector. Go to step 1. If any other Temporary DTCs or DTCs are set, go to the indicated DTC and troubleshoot. If DTC P0627 are not set, PCM was updated, troubleshooting is done. If PCM was substituted, replace original PCM.

DTC P0641 OR DTC P0651

Code Definition

1. DTC P0641: Sensor Reference Voltage "A" Circuit Malfunction
2. DTC P0651: Sensor Reference Voltage "B" Circuit Malfunction

Note. This test covers both "A" and "B" sensor reference voltage circuit malfunctions. The information will be shown "A" first and "B" second. When discussion arises, "A" sensors and circuit terminals will precede "B" sensors and circuit terminals. Furthermore "B" sensors and circuit terminals information will be enclosed in parantheses ( ).

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0641 is set, go to step 3 . Or if DTC P0651 is set, go to step 12 . If DTCs P0641 and/or P0651 are not set, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at the following connectors: MAP Sensor APP sensor 1 Countershaft Speed Sensor (Throttle Actuator Control Module) (Mainshaft Speed Sensor) (EGR Valve Position Sensor) (APP Sensor 2) (FTP Sensor)
3. Turn ignition off. Disconnect MAP sensor 3-pin connector.
4. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
5. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0641 is set, go to step 6 . If DTC P0641 is not set, replace MAP sensor and go to step 35 .
6. Turn ignition off. Disconnect APP sensor 1 6-pin connector.
7. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
8. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0641 is set, go to step 9 . If DTC P0641 is not set, replace APP sensor 1 and go to step 35 .
9. Turn ignition off. Disconnect (countershaft speed sensor) 3-pin connector.
10. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
11. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0651 is set, go to step 32 . If DTC P0651 is not set, replace (countershaft speed sensor) and go to step 40 .
12. Turn ignition off.
13. Disconnect (throttle actuator control module) 16-pin connector.
14. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
15. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0651 is set, go to next step. If DTC P0651 is not set, replace (throttle actuator control module) and go to step 40 .
16. Turn ignition off.
17. Disconnect (mainshaft speed sensor) 3-pin connector.
18. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
19. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0651 is set, go to next step. If DTC P0651 is not set, replace (mainshaft speed sensor) and go to step 40 .
20. Turn ignition off.
21. Disconnect (EGR position sensor) 5-pin connector.
22. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
23. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0651 is set, go to next step. If DTC P0651 is not set, replace (EGR position sensor) and go to step 40 .
24. Turn ignition off.
25. Disconnect (APP sensor 2) 6-pin connector.
26. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
27. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0651 is set, go to next step. If DTC P0651 is not set, replace (APP sensor 2) and go to step 40 .
28. Turn ignition off.
29. Disconnect (FTP sensor) 3-pin connector.
30. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
31. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0651 is set go to next step. If DTC P0651 is not set, replace (FTP sensor) and go to step 40 .
32. Turn ignition off. Disconnect PCM harness connector "A".
33. Disconnect PCM harness connector "B".
34. Check for continuity between ground and PCM harness connector terminals A7 (A27), B43 (B29) and B46. If there is continuity, repair short in wire between ground and PCM harness connector terminals A7 (A27), B43 (B29) and B46. If there is no continuity, go to step 40 .
35. Turn ignition on.
36. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Go to next step.
37. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) .
38. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0641 or DTC P0651 are set, check for poor connections or loose terminals at the PCM and the following connectors: MAP Sensor APP Sensor 1 Countershaft Speed Sensor (Throttle Actuator Control Module) (Mainshaft Speed Sensor) (EGR Valve Position Sensor) (APP Sensor 2) (FTP Sensor) After checking above list. Go to step 1 . If any other Temporary DTCs or DTCs are set, go to the indicated DTC and troubleshoot. If DTCs P0641 or DTC P0651 are not set, troubleshooting is done.
39. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) .
40. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0641 or DTC P0651 are set, check for poor connections or loose terminals at the PCM and the following connectors: MAP Sensor APP Sensor 1 Countershaft Speed Sensor (Throttle Actuator Control Module) (Mainshaft Speed Sensor) (EGR Valve Position Sensor) (APP Sensor 2) (FTP Sensor) After checking above list. Go to step 1 . If any other Temporary DTCs or DTCs are set, go to the indicated DTC and troubleshoot. If DTCs P0641 or DTC P0651 are not set and PCM was updated, troubleshooting is done. If PCM was substituted, replace original PCM.

DTC P0657: AIR FUEL RATIO SENSOR RELAY CIRCUIT MALFUNCTION

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0657 is set, go to next step. If DTC P0657 is not set, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at PCM and A/F ratio sensor relay and No. 9 LAF HT (15-amp) fuse in the under-hood sub-fuse box.
3. Turn ignition off. Disconnect PCM harness connector "B". (Scheme 4)
4. Remove A/F sensor relay.
5. Check for continuity between PCM harness connector terminal B10 (Orange wire) and A/F sensor relay 4-pin connector terminal No. 3. If there is continuity, go to next step. If there is no continuity, repair open in wire between PCM harness connector terminal B10 (Orange wire) and A/F sensor relay 4-pin connector terminal No. 3. Go to step 7.
6. Measure voltage between ground and A/F sensor relay 4-pin connector terminal No. 4 (White/Red wire). If there is battery voltage, go to step 11. If there is no battery voltage, repair open in wire between A/F sensor relay 4-pin connector terminal No. 4 (White/Red wire) and No. 9 LAF HT (15-amp) fuse in the under-hood sub-fuse box.
7. Install the A/F sensor relay. Reconnect PCM harness connector "B".
8. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Go to next step.
9. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
10. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0657 is set, check for poor connections or loose terminals at PCM and A/F ratio sensor relay. Go to step 1. If any other Temporary DTCs or DTCs are set, go to the indicated DTC and troubleshoot. If DTC P0657 is not set, troubleshooting is done.
11. Test the A/F sensor relay. (Scheme 18) If relay is OK, go to step 15. If relay is no good, replace A/F sensor relay and go to next step.
12. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Go to next step.
13. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
14. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0657 is set, check for poor connections or loose terminals at PCM and A/F ratio sensor relay. Go to step 1. If any other Temporary DTCs or DTCs are set, go to the indicated DTC and troubleshoot. If DTC P0657 is not set, troubleshooting is done.
15. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
16. Turn ignition on.
17. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0657 is set, check for poor connections or loose terminals at PCM and A/F ratio sensor relay. Go to step 1. If any other Temporary DTCs or DTCs are set, go to the indicated DTC and troubleshoot. If no Temporary DTCs or DTCs are set and PCM was updated, troubleshooting is done. If PCM was substituted, replace original PCM.

Scheme 18

DTC P0685: PCM POWER CONTROL CIRCUIT MALFUNCTION

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Wait 1 second.
3. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0685 is set, update the PCM if it does not have the latest software, or substitute a known-good PCM. If the problem goes away with a known-good PCM, replace PCM. If DTC P0685 is not set, problem is intermittent, system is OK at this time.

DTC P1077: INTAKE MANIFOLD RUNNER CONTROL VALVE STUCK SHORT

Note. If DTC P0651 is indicated at the same time as DTC P1077, troubleshoot P0651 first, then recheck for DTC P1077.

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Using Honda PGM Tester or the HDS, make sure IMRC SOL is OFF in the DATA list of the CLEAR menu. Check IMRC VLV SW in the DATA list. If it is CLOSED, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at intake manifold runner control (IMRC) actuator and PCM connectors. If it is not CLOSED, go top next step.
3. Turn ignition off. Disconnect IMRC actuator 5-pin connector. Go to next step.
4. Turn ignition on. Using Honda PGM Tester or the HDS, check IMRC VLV SW in the DATA list. If it is CLOSED, go to step 6. If it is not CLOSED, go top next step.
5. Turn ignition off. Disconnect PCM harness connector "A". (Scheme 4) Check for continuity between ground and PCM harness connector terminal A41 (White/Black wire). If there is continuity, repair short in wire between PCM harness connector terminal A41 and IMRC actuator. If there is no continuity, go to step 15.
6. Turn ignition on. Measure voltage between ground and IMRC actuator 5-pin connector terminal No. 1 (Yellow/Blue wire). If there is about 5 volts, go to next step. If there is not about 5 volts, repair open in wire between PCM harness connector terminal A27 and IMRC actuator 5-pin connector terminal No. 1. Go to step 13.
7. Turn ignition off. Check for continuity between PCM harness connector terminal A9 (White/Blue wire) and IMRC actuator 5-pin connector terminal No. 5. If there is continuity, go to next step. If there is no continuity, repair open in wire between PCM harness connector terminal A9 and IMRC actuator 5-pin connector terminal No. 5. Go to step 13.
8. Check for continuity between ground and PCM harness connector terminal A9 (White/Blue wire). If there is continuity, repair short in wire between PCM harness connector terminal A9 and IMRC actuator. If there is no continuity, go to step 13.
9. Turn ignition off. Check for continuity between PCM harness connector terminal A10 (White/Red wire) and IMRC actuator 5-pin connector terminal No. 4. If there is continuity, go to next step. If there is no continuity, repair open in wire between PCM harness connector terminal A10 and IMRC actuator 5-pin connector terminal No. 4. Go to step 13.
10. Check for continuity between ground and PCM harness connector terminal A10 (White/Red wire). If there is continuity, repair short in wire between PCM harness connector terminal A10 and IMRC actuator. Go to step 13. If there is no continuity, go to next step.
11. Remove the intake manifold runner control valve actuator.
12. Move the intake manifold runner control valve by hand. If it moves smoothly, replace the IMRC valve actuator. Go to step 14. If it does not move smoothly, remove the intake manifold upper cover and repair the stuck valve. If necessary, replace the intake manifold. Go to next step.
13. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Go to next step.
14. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Using Honda PGM Tester or the HDS, check for Temporary DTCs or DTCs in the DTC menu. If DTC P1077 is set, check for poor connections or loose terminals at IMRC valve actuator. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, troubleshooting is done.
15. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1077, check for poor connections or loose terminals at IMRC valve actuator and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P1078: INTAKE MANIFOLD RUNNER CONTROL VALVE STUCK LONG

1. Turn ignition on. DO NOT start engine. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Using Honda PGM Tester or the HDS, make sure IMRC SOL is ON in the DATA list. Check IMRC VLV SW in the DATA list. If it is OPEN, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at intake manifold runner control (IMRC) actuator and PCM connectors. If it is not OPEN, go top next step.
3. Turn ignition off. Disconnect IMRC actuator 5-pin connector. Go to next step.
4. Turn ignition on. Measure voltage between ground and IMRC actuator 5-pin connector terminal No. 3 (White/Black wire). If there is about 5 volts, go to next step. If there is not about 5 volts. Go to step 6.
5. Turn ignition off. Disconnect PCM harness connector "A". (Scheme 4) Check for continuity between PCM harness connector terminal A28 (Green/Yellow wire) and IMRC actuator 5-pin connector terminal No. 2. If there is continuity, go to step 7. If there is no continuity, repair open in wire between PCM harness connector terminal A28 and IMRC actuator 5-pin connector terminal No. 2. Go to step 13.
6. Turn ignition off. Disconnect PCM harness connector "A". Check for continuity between PCM harness connector terminal A41 (White/Black wire) and IMRC actuator 5-pin connector terminal No. 3. If there is continuity, go to step 15. If there is no continuity, repair open in wire between PCM harness connector terminal A41 and IMRC actuator 5-pin connector terminal No. 3. Go to step 13.
7. Check for continuity between PCM harness connector terminal A9 (White/Blue wire) and IMRC actuator 5-pin connector terminal No. 5. If there is continuity, go to next step. If there is no continuity, repair open in wire between PCM harness connector terminal A9 and IMRC actuator 5-pin connector terminal No. 5. Go to step 13.
8. Check for continuity between ground and PCM harness connector terminal A9 (White/Blue wire). If there is continuity, repair short in wire between PCM harness connector terminal A9 and IMRC actuator. Go to step 13. If there is no continuity, go to next step.
9. Check for continuity between PCM harness connector terminal A10 (White/Red wire) and IMRC actuator 5-pin connector terminal No. 4. If there is continuity, go to next step. If there is no continuity, repair open in wire between PCM harness connector terminal A10 and IMRC actuator 5-pin connector terminal No. 4. Go to step 13.
10. Check for continuity between ground and PCM harness connector terminal A10 (White/Red wire). If there is continuity, repair short in wire between PCM harness connector terminal A10 and IMRC actuator. Go to step 13. If there is no continuity, go to next step.
11. Remove the intake manifold runner control valve actuator.
12. Move the intake manifold runner control valve by hand. If it moves smoothly, replace the IMRC valve actuator. Go to next step. If it does not move smoothly, remove the intake manifold upper cover and repair the stuck valve. If necessary, replace the intake manifold. Go to next step.
13. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Go to next step.
14. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Using Honda PGM Tester or the HDS, check for Temporary DTCs or DTCs in the DTC menu. If DTC P1078 is set, check for poor connections or loose terminals at IMRC valve actuator. Go to 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, troubleshooting is done.
15. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1078, check for poor connections or loose terminals at IMRC valve actuator and PCM harness connector. Go to 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P1128: MANIFOLD ABSOLUTE PRESSURE SENSOR SIGNAL LOWER THAN EXPECTED

1. Turn ignition switch on. Using Honda PGM Tester or the HDS, check MAP sensor in the DATA list. If MAP reading is 54.1 kPa or 1.61 volt or more for more than 5 seconds, go to step 5 . If MAP sensor reading is not as specified, go to next step.
2. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu. Start engine . Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle.
3. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). Engine speed between 1100 and 6000 RPM. A/T in "D" position. Vehicle speed is accelerated from 16 MPH to 31 MPH with half throttle.
4. Using Honda PGM Tester or the HDS, monitor the OBD STATUS for DTC P1128 in the DTCs menu. If it is FAILED, go to next step. If it is PASSED problem is intermittent, system is OK at this time. If it is NOT COMPLETED, go to step 2 and recheck.
5. Turn ignition off. Replace the MAP sensor. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) .
6. Start engine . Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). Engine speed between 1100 and 6000 RPM. A/T in "D" position. Vehicle speed is accelerated from 16 MPH to 31 MPH with half throttle.
7. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1128 is set, check for poor connections or loose terminals at MAP sensor and PCM harness connectors. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, go to next step.
8. Monitor the OBD STATUS for DTC P1128 in the DTCs menu with the Honda PGM tester or the HDS. If it PASSED, troubleshooting is done. If it is FAILED, check for poor connections or loose terminals at MAP sensor and PCM harness connectors. Go to step 1 . If it is NOT COMPLETED, go to step 6 .

DTC P1129: MANIFOLD ABSOLUTE PRESSURE SENSOR SIGNAL HIGHER THAN EXPECTED

1. Check for vacuum leaks in the following areas: PCV Valve PCV Hose EVAP Canister Purge Valve Throttle Body Brake Booster Hose Engine Mount Control Solenoid Valve, Hose And Pipe If no leaks are found, go to next step. If leaks are found, Repair or replace parts as necessary. Go to step 6 .
2. Start engine . Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle. Using Honda PGM Tester or the HDS, check MAP sensor in the DATA list. If MAP reading is 36.9 kPa or 1.14 volt or more for more than 5 seconds, go to step 6 . If MAP sensor reading is not as specified, go to next step.
3. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
4. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). Engine speed between 1100 and 6000 RPM. A/T in "D" position. Vehicle speed is accelerated from 16 MPH to 31 MPH with half throttle.
5. Monitor the OBD STATUS for DTC P1129 in the DTCs menu with the Honda PGM tester or the HDS. If it PASSED, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at MAP sensor and PCM harness connectors. If it is FAILED. Go to next step. If it is NOT COMPLETED, go to step 4 .
6. Turn ignition off. Replace the MAP sensor. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) .
7. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). Engine speed between 1100 and 6000 RPM. A/T in "D" position. Vehicle speed is accelerated from 16 MPH to 31 MPH with half throttle.
8. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1129 is set, check for poor connections or loose terminals at MAP sensor and PCM harness connectors. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, go to next step.
9. Monitor the OBD STATUS for DTC P1129 in the DTCs menu with the Honda PGM tester or the HDS. If it PASSED, troubleshooting is complete. If it is FAILED, check for poor connections or loose terminals at MAP sensor and PCM harness connectors Go to 1 . If it is NOT COMPLETED, go to step 7 and recheck.

DTC P1297: ELECTRICAL LOAD DETECTOR CIRCUIT, LOW VOLTAGE

1. Turn ignition on. Check the ELD in the DATA list with the Honda PGM tester or the HDS. If about 72-amps or more is indicated, go to next step. If about 72-amps or more is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at ELD connector and the PCM connector.
2. Turn ignition switch off. Disconnect PCM harness connector "B". (Scheme 4) Check for continuity between ground and PCM harness connector terminal B25 (Green/Red wire). (Scheme 4) If continuity is present, repair short in wire between PCM harness connector terminal B25 and ELD 3-pin harness connector. Go to step 4. If continuity is not present, go to step 8.
3. Turn ignition off.
4. Replace the under-hood fuse/relay box, the ELD unit is built-in. Go to next step.
5. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
6. Start engine. Turn headlights on. Go to next step.
7. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1297 is set, check for poor connections or loose terminals at ELD and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, troubleshooting is done.
8. Update the PCM if it does not have the latest software, or substitute a know-good PCM.
9. Start engine. Turn headlights on. Go to next step.
10. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1297 is set, check for poor connections or loose terminals at ELD and PCM harness connectors. Go to 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, PCM was updated, troubleshooting is done. If PCM was substituted, replace the original PCM.

DTC P1298: ELECTRICAL LOAD DETECTOR CIRCUIT, HIGH VOLTAGE

1. Turn ignition on. Check the ELD in the DATA list with the Honda PGM tester or the HDS. If about 0.2-amps or less is indicated, go to next step. If about 0.2-amps or less is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at ELD connector and the PCM connector.
2. Turn ignition off. Disconnect ELD 3-pin harness connector. (Scheme 19) Turn ignition switch on. Measure voltage between ground and ELD 3-pin harness connector terminal No. 1 (Green/White wire). If battery voltage is present, go to next step. If battery voltage is not present, check No. 9 LAF (15-amp) fuse in under-hood sub-fuse box. If fuse is OK, repair open in Green/White wire between 15-amp fuse in under-hood sub-fuse box and ELD 3-pin harness connector terminal No. 1. See appropriate wiring diagram under ENGINE PERFORMANCE in WIRING DIAGRAMS. Repair as necessary.
3. Turn ignition switch off. Disconnect PCM harness connector "B". (Scheme 4) Check for continuity between PCM harness connector terminal B25 (Blue/Black wire) and ELD connector terminal No. 3. (Scheme 4) If continuity is present, go to next step. If continuity is not present, repair open in wire between PCM harness connector terminal B25 and ELD 3-pin harness connector terminal No. 3.
4. Check for continuity between ground and ELD 3-pin connector terminal No. 2 (Black wire). If there is continuity, go to next step. If there is no continuity, Repair open in wire between ground connector G201 and ELD 3-pin connector terminal No. 2
5. Replace the under-hood fuse/relay box, the ELD unit is built-in. Go to next step.
6. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
7. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1298 is set, go to next step. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, troubleshooting is done.
8. Update the PCM if it does not have the latest software, or substitute a know-good PCM.
9. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1298 is set, check for poor connections or loose terminals at ELD and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, PCM was updated, troubleshooting is done. If PCM was substituted, replace the original PCM.

Scheme 19

DTC P1450: TWO WAY VALVE BYPASS VALVE CONTROL CIRCUIT, LOW VOLTAGE

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Using Honda PGM Tester or the HDS, do the BPS CLOSE in the INSPECTION menu. Wait 5 seconds. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1450 is set, go to step 4. If Temporary DTCs or DTCs are not set, go to next step.
3. Using Honda PGM Tester or the HDS, do the EVAP BPS ON in the INSPECTION menu. Wait 5 seconds. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1450 is set, go to next step. If Temporary DTCs or DTCs are not set, problem is intermittent, system is OK. Check for poor connections or loose terminals at EVAP bypass solenoid valve 2-pin connector.
4. Turn ignition off. Disconnect EVAP bypass solenoid valve 2-pin connector. Measure resistance between EVAP bypass solenoid valve terminals No. 1 and 2. If there is about 30-40 ohms, go to next step. If there is not about 30-40 ohms, go to step 8.
5. Turn ignition on. Measure voltage between ground and EVAP bypass solenoid valve terminals No. 1 (Yellow/Black wire). If battery voltage is present, go to next step. If battery voltage is present, repair open in wire between EVAP bypass solenoid valve terminals No. 1 and A/F relay. Go to step 9.
6. Turn ignition off. Disconnect PCM harness connector "B". (Scheme 4) Check for continuity between ground and PCM harness connector terminal B7. If there is continuity, repair short in wire between PCM and EVAP bypass solenoid valve. Go to next step. If there is no continuity, go to step 11.
7. With a fused jumper wire connect EVAP bypass solenoid valve connector terminal No. 2 (Orange/White wire) to ground. Check for continuity between ground and PCM harness connector terminal B7. If there is continuity, go to step 11. If there is no continuity, repair open in wire between PCM and EVAP bypass solenoid valve. Go to next step.
8. Replace EVAP bypass solenoid valve. Reconnect PCM harness connector "B" and EVAP bypass solenoid valve 2-pin connector.
9. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
10. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1450 is set, go to next step. If Temporary DTC or DTC P1450 is set, check for poor connections or loose terminals at EVAP bypass solenoid valve 2-pin connector Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs, go to next step.
11. Update the PCM if it does not have the latest software, or substitute a know-good PCM.
12. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1450 is set, check for poor connections or loose terminals at EVAP bypass solenoid valve and PCM harness connectors. Go to 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, PCM was updated, troubleshooting is done. If PCM was substituted, replace the original PCM.
13. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P1450 in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED, check for poor connections or loose terminals at EVAP bypass solenoid valve and PCM harness connectors. Go to step 1. If it is NOT COMPLETED, go to step 4 and recheck.

DTC P1451: TWO WAY VALVE BYPASS VALVE CONTROL CIRCUIT, HIGH VOLTAGE

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Using Honda PGM Tester or the HDS, do the BPS CLOSE in the INSPECTION menu. Wait 5 seconds. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1451 is set, update the PCM if it does not have the latest software, or substitute a know-good PCM. If problem goes away with a known-good PCM, replace PCM. If Temporary DTCs or DTCs are not set, problem is intermittent, system is OK at this time.

DTC P1454: FUEL TANK PRESSURE SENSOR RANGE/PERFORMANCE PROBLEM

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Turn ignition off. Remove fuel fill cap and wait 1 minute. Using Honda PGM Tester or the HDS, check the FTP SENSOR in the DATA list. If there is between 0.67 kPa (0.2 in.Hg) or 2.3-2.7 volts, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at the FTP sensor and PCM. If there is more or less than 0.67 kPa (0.2 in.Hg) or 2.3-2.7 volts, go to next step.
3. Remove FTP sensor with its connector connected. See "A" in (Scheme 20). Using Honda PGM Tester or the HDS, check the FTP SENSOR in the DATA list. If there is between 0.67 kPa (0.2 in.Hg) or 2.3-2.7 volts, check for debris or clogging in the EVAP canister and FTP sensor. Go to next step. If there is more or less than 0.67 kPa (0.2 in.Hg) or 2.3-2.7 volts, check for debris or clogging in the FTP sensor air tube. If air tube is OK, replace FTP sensor. Go to next step.
4. Install FTP sensor to the EVAP canister. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
5. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1454 is set, check for poor connections or loose terminals at FTP sensor and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, go to next step.
6. Turn ignition off. Remove fuel fill cap and wait 1 minute. Using Honda PGM Tester or the HDS, check the FTP SENSOR in the DATA list. If there is between 0.67 kPa (0.2 in.Hg) or 2.3-2.7 volts, troubleshooting is done. If there is more or less than 0.67 kPa (0.2 in.Hg) or 2.3-2.7 volts, check for poor connections or loose terminals at the FTP sensor and PCM. Go to step 1.

Scheme 20

DTC P1460: FUEL LEVEL SENSOR POWER SUPPLY CIRCUIT

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Using Honda PGM Tester or the HDS, check the FUEL REF VOL, FUEL LEVEL SENSOR in the DATA list. Subtract the voltage of FLEVEL 2 from the voltage of FLEVEL 1. If there is 0.198 volt or more, go to next step. If there is not 0.198 volt or more, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at the gauge assembly and PCM.
3. Turn ignition off. Disconnect PCM harness connector "B". (Scheme 4) Turn ignition on. Measure voltage between ground and PCM harness connector terminal B51 (Light Green/White wire). If there is battery voltage, go to step 7. If there is not battery voltage, go to next step.
4. Turn ignition off. Disconnect the gauge assembly 14-pin connector "C". (Scheme 21) Check for continuity between PCM harness connector terminal B51 (Light Green/White wire) and gauge assembly 14-pin connector terminal C6. If there is continuity, replace gauge assembly. Go to next step. If there is no continuity, repair open in wire between PCM harness connector terminal B51 (Light Green/White wire) and gauge assembly 14-pin connector terminal C6. Go to next step.
5. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
6. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1460 is set, check for poor connections or loose terminals at gauge assembly and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, troubleshooting is done.
7. Update the PCM if it does not have the latest software, or substitute a know-good PCM.
8. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1460 is set, check for poor connections or loose terminals at gauge assembly and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, PCM was updated, troubleshooting is done. If PCM was substituted, replace the original PCM.

Scheme 21

DTC P1683: THROTTLE VALVE DEFAULT POSITION SPRING PERFORMANCE PROBLEM

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle. Turn ignition off.
2. Turn ignition on. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1683 is set, go to next step. If DTC P1683 is not set, check for poor connections or loose terminals at throttle body and at throttle actuator control module.
3. Turn ignition off. Disconnect air intake duct from throttle body. Push throttle valve closed. (Scheme 22) Release throttle valve. If throttle valve returns, go to next step. If throttle valve does not return, go to step 5.
4. Remove throttle body for cleaning. Be careful not to pinch fingers. (Scheme 23) Wipe off carbon deposits on throttle valve and inside throttle bore with a paper towel soaked in carburetor cleaner. Install throttle body. Go to step 6.
5. Replace throttle body.
6. Turn ignition on. Using Honda PGM Tester or the HDS, do the PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Turn ignition off.
7. Turn ignition on. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1683 is set, go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTC P1683 is not set, troubleshooting is complete.

Scheme 22

Scheme 23

DTC P1684: THROTTLE VALVE RETURN SPRING PERFORMANCE PROBLEM

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle.
2. Turn ignition on. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1684 is set, go to next step. If DTC P1684 is not set, check for poor connections or loose terminals at throttle body and at throttle actuator control module.
3. Turn ignition off. Disconnect air intake duct from throttle body. Push throttle valve open. (Scheme 24) Release throttle valve. If throttle valve returns, go to next step. If throttle valve does not return, go to step 5.
4. Remove throttle body for cleaning. Be careful not to pinch fingers. (Scheme 23) Wipe off carbon deposits on throttle valve and inside throttle bore with a paper towel soaked in carburetor cleaner. Install throttle body. Go to step 6.
5. Replace throttle body.
6. Turn ignition on. Using Honda PGM Tester or the HDS, do the PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Turn ignition off.
7. Turn ignition on. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P1684 is set, go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTC P1684 is not set, troubleshooting is complete.

Scheme 24

DTC P2101: THROTTLE ACTUATOR SYSTEM MALFUNCTION

Note. Turn ignition on. Using Honda PGM Tester or the HDS, record the following freeze frame data: Engine speed. Vehicle speed. Accelerator position.

1. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Using Honda PGM Tester or the HDS, do the TAC TEST in the INSPECTION menu.
3. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2101 is set, go to step 5. If DTC P2101 is not set, go to next step.
4. Test drive vehicle for several minutes in the range of recorded freeze frame data. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2101 is set, go to step 5. If DTC P2101 is not set, problem is intermittent. System is OK at this time. Check for poor connections or loose terminals at throttle actuator control module and PCM, then clean throttle body. Remove throttle body for cleaning. Be careful not to pinch fingers. (Scheme 23) Wipe off carbon deposits on throttle valve and inside throttle bore with a paper towel soaked in carburetor cleaner. Install throttle body. Go to step 8.
5. Turn ignition off. Disconnect air intake duct from throttle body. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu. Do the TAC TEST in the INSPECTION menu.
6. Watch throttle valve movement. If throttle valve moves smoothly, go to step 10. If throttle valve does not move smoothly, then clean throttle body. Remove throttle body for cleaning. Be careful not to pinch fingers. (Scheme 23) Wipe off carbon deposits on throttle valve and inside throttle bore with a paper towel soaked in carburetor cleaner. Install throttle body. Then recheck for Temporary DTCs or DTCs in the DTC menu. If DTC P2101 is set, go to next step.
7. Turn ignition off. Replace throttle body. Go to next step.
8. Turn ignition on. Using Honda PGM Tester or the HDS, do the PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
9. Test drive vehicle for several minutes in the range of recorded freeze frame data. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2101 is set, check for poor connections or loose terminals at throttle actuator control module and PCM Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTC P2101 is not set, troubleshooting is complete.
10. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2101, check for poor connections or loose terminals at throttle actuator control module and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P2108: THROTTLE ACTUATOR CONTROL MODULE PROBLEM

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Turn ignition off. Then turn ignition on. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2108 is set, substitute a known-good throttle body assembly and recheck. If problem is gone, replace original throttle body assembly. If DTC P2108 is not set, problem is intermittent. System is OK at this time. Check for poor connections or loose terminals at throttle actuator control module and PCM.

DTC P2118: THROTTLE ACTUATOR CONTROL MODULE RANGE/PERFORMANCE PROBLEM

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Press accelerator several times. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2118 is set, go to next step. If DTC P2118 is not set, problem is intermittent. System is OK at this time. Check for poor connections or loose terminals at throttle actuator control module and PCM.
3. Turn ignition off. Replace throttle body assembly. Turn ignition on. Using Honda PGM Tester or the HDS, do the PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Go to next step.
4. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2118 is set, update the PCM if it does not have the latest software, or substitute a known-good PCM. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . If DTC P2118 is not set, troubleshooting is done.

DTC P2122: ACCELERATOR PEDAL POSITION (APP) SENSOR 1 CIRCUIT, LOW VOLTAGE

Note. If DTC P0641 is set at the same time as DTC P2122, troubleshoot DTC P0641 first, then recheck for DTC P2122.

1. Turn ignition on. Check the APP SENSOR 1 in the DATA list with the Honda PGM tester or the HDS. If about 0° or 0.1 volt or lower is indicated, go to next step. If about 0° or 0.1 volt or lower is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at APP sensor 1 connector and the PCM connector.
2. Turn ignition off. Disconnect APP sensor 6-pin connector. Turn ignition on. Measure voltage between APP harness connector terminals No.5 (Yellow/Black wire) and 6 (Black wire). If there is about 5 volts, go to next step. If there is not about 5 volts, go to step 7.
3. Turn ignition off. Measure resistance between APP sensor 1 terminals No. 4 and 6. If there is between 0.35-0.45K ohms, go to next step. If there is not between 0.35-0.45K ohms, go to step 8.
4. Measure resistance between APP sensor 1 terminals No. 4 and 5. If there is between 2.7-3.3K ohms, go to next step. If there is not between 2.7-3.3K ohms, go to step 8
5. Disconnect PCM harness connector "B". (Scheme 4) Check continuity between ground and APP sensor 1 harness connector terminal No. 4 (Green/Yellow wire). If there is continuity, repair short in wire between APP sensor 1 harness connector terminal No. 4 and PCM harness connector terminal B44. If there is no continuity, go to next step.
6. Check continuity between PCM harness connector terminal B44 and APP sensor 1 harness connector terminal No. 4 (Green/Yellow wire). If there is continuity, go to step 10. If there is no continuity, repair open in wire between APP sensor 1 harness connector terminal No. 4 and PCM harness connector terminal B44.
7. Check continuity between PCM harness connector terminal B43 and APP sensor 1 harness connector terminal No.5 (Yellow/Black wire). If there is continuity, go to step 10. If there is no continuity, repair open in wire between APP sensor 1 harness connector terminal No. 5 and PCM harness connector terminal B43.
8. Replace APP sensor 1. Go to next step
9. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2122 is set, check for poor connections or loose terminals at APP sensor 1 connector and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.
10. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2122, check for poor connections or loose terminals at APP sensor 1 and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P2123: ACCELERATOR PEDAL POSITION (APP) SENSOR 1 CIRCUIT, HIGH VOLTAGE

1. Turn ignition on. Check the APP SENSOR 1 in the DATA list with the Honda PGM tester or the HDS. If about 88° or 4.85 volts or higher is indicated, go to next step. If about 88° or 4.85 volts or higher is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at APP sensor 1 connector and the PCM connector.
2. Turn ignition off. Disconnect APP sensor 6-pin connector. Turn ignition on. Measure voltage between APP harness connector terminals No.5 (Yellow/Black wire) and 6 (Black wire). If there is about 5 volts, go to next step. If there is not about 5 volts, go to step 4.
3. Disconnect PCM harness connector "B". (Scheme 4) Check continuity between PCM harness connector terminal B43 and APP sensor 1 harness connector terminal No.5 (Yellow/Black wire). If there is continuity, go to step 7. If there is no continuity, repair open in wire between APP sensor 1 harness connector terminal No. 5 and PCM harness connector terminal B43. Go to step 5.
4. Replace APP sensor 1. Go to next step
5. Reconnect PCM harness connector "B".
6. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2123 is set, check for poor connections or loose terminals at APP sensor 1 connector and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.
7. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2123, check for poor connections or loose terminals at APP sensor 1 and PCM harness connector. Go to 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P2127: ACCELERATOR PEDAL POSITION (APP) SENSOR 2 CIRCUIT, LOW VOLTAGE

Note. If DTC P0651 is set at the same time as DTC P2127, troubleshoot DTC P0651 first, then recheck for DTC P2127.

1. Turn ignition on. Check the APP SENSOR 2 in the DATA list with the Honda PGM tester or the HDS. If about 0° or 0.1 volt or lower is indicated, go to next step. If about 0° or 0.1 volt or lower is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at APP sensor 2 connector and the PCM connector.
2. Turn ignition off. Disconnect APP sensor 6-pin connector. Turn ignition on. Measure voltage between APP harness connector terminals No. 1 (Yellow/White wire) and 2 (Black wire). If there is about 5 volts, go to next step. If there is not about 5 volts, go to step 7.
3. Turn ignition off. Measure resistance between APP sensor 2 terminals No. 2 and 3. If there is between 0.35-0.45K ohms, go to next step. If there is not between 0.35-0.45K ohms, go to step 8.
4. Measure resistance between APP sensor 2 terminals No. 1 and 3. If there is between 5.6-6.8K ohms, go to next step. If there is not between 5.6-6.8K ohms, go to step 8
5. Disconnect PCM harness connector "B". (Scheme 4) Check continuity between ground and APP sensor 2 harness connector terminal No. 3 (Pink/Black wire). If there is continuity, repair short in wire between APP sensor 2 harness connector terminal No. 3 and PCM harness connector terminal B30. If there is no continuity, go to next step.
6. Check continuity between PCM harness connector terminal B30 and APP sensor 2 harness connector terminal No. 3 (Pink/Black wire). If there is continuity, go to step 10. If there is no continuity, repair open in wire between APP sensor 2 harness connector terminal No. 3 and PCM harness connector terminal B30.
7. Check continuity between PCM harness connector terminal B29 and APP sensor 2 harness connector terminal No. 1 (Yellow/White wire). If there is continuity, go to step 10. If there is no continuity, repair open in wire between APP sensor 2 harness connector terminal No. 1 and PCM harness connector terminal B29.
8. Replace APP sensor 2. Go to next step
9. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2127 is set, check for poor connections or loose terminals at APP sensor 2 connector and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.
10. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2127, check for poor connections or loose terminals at APP sensor 2 and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P2128: ACCELERATOR PEDAL POSITION (APP) SENSOR 2 CIRCUIT, HIGH VOLTAGE

1. Turn ignition on. Check the APP SENSOR 2 in the DATA list with the Honda PGM tester or the HDS. If about 186° or 4.8 volts or higher is indicated, go to next step. If about 186° or 4.8 volts or higher is not indicated, problem is intermittent, system is OK at this time. Check for poor connection at APP sensor 2 connector and the PCM connector.
2. Turn ignition off. Disconnect APP sensor 6-pin connector. Turn ignition on. Measure voltage between APP harness connector terminals No. 1 (Yellow/White wire) and 2 (Black wire). If there is about 5 volts, go to next step. If there is not about 5 volts, go to step 4.
3. Disconnect PCM harness connector "B". (Scheme 4) Check continuity between PCM harness connector terminal B29 and APP sensor 2 harness connector terminal No. 1 (Yellow/White wire). If there is continuity, go to step 7. If there is no continuity, repair open in wire between APP sensor 2 harness connector terminal No. 1 and PCM harness connector terminal B29. Go to step 5.
4. Replace APP sensor 2. Go to next step
5. Reconnect PCM harness connector "B".
6. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2128 is set, check for poor connections or loose terminals at APP sensor 2 connector and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.
7. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2128, check for poor connections or loose terminals at APP sensor 2 and PCM harness connector. Go to 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P2135: THROTTLE POSITION SENSOR 1 & 2, INCORRECT VOLTAGE CORRELATION

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu. Wait 10 seconds.
2. Check for Temporary DTCs or DTCs in the DTC menu. If any Temporary DTCs or DTCs are set, go to step 4 . If any Temporary DTCs or DTCs are not set, go to next step.
3. Using Honda PGM Tester or the HDS, do the ETCS test in the INSPECTION menu. Check for Temporary DTCs or DTCs in the DTC menu. If any Temporary DTCs or DTCs are set, go to next step. If any Temporary DTCs or DTCs are not set, problem is intermittent. System is OK. Check for poor connections or loose terminals at throttle actuator control module and at PCM harness connector.
4. Turn ignition off. Replace throttle body.
5. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2135 is set, check for poor connections or loose terminals at throttle actuator control module and at PCM harness connector. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.

DTC P2138: ACCELERATOR PEDAL POSITION (APP) SENSOR 1 & 2, INCORRECT VOLTAGE CORRELATION

1. Turn ignition on. Check the APP SENSOR 1 and the APP SENSOR 2 in the DATA list with the Honda PGM tester or the HDS. If APP sensor 1 & 2 change to the same throttle angle as the throttle is opened fully, problem is intermittent, system is OK at this time. Check for poor connection at APP sensor connector and the PCM connector. If APP sensor 1 & 2 do not change to the same throttle angle as the throttle is opened fully, go to next step.
2. Check the APP SENSOR 1 and the APP SENSOR 2 in the DATA list with the Honda PGM tester or the HDS. If APP sensor 1 & 2 have the same voltage, go to next step. If APP sensor 1 & 2 do not have the same voltage, go to step 5.
3. Turn ignition off. Disconnect AAP sensor 6-pin connector. Disconnect PCM harness connector "B". (Scheme 4)
4. Check continuity between ground an PCM harness connector terminals B30 (Pink/Black wire) and B44 (Green/Yellow wire) individually. If there is continuity, repair short in wire between ground an PCM harness connector terminals B30 (Pink/Black wire) and B44 (Green/Yellow wire). Go to step 6. If there is no continuity. Go to step 8.
5. Replace the APP sensor.
6. Reconnect PCM harness connector "B".
7. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2138 is set, check for poor connections or loose terminals at APP sensor connector and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.
8. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2138, check for poor connections or loose terminals at APP sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P2176: THROTTLE ACTUATOR CONTROL SYSTEM, IDLE POSITION NOT LEARNED

Note. If DTC P2135 is stored at the same time as DTC P2176, troubleshoot DTC P2135 first, then recheck for DTC P2176.

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu. Turn ignition off.
2. Turn ignition on, wait 10 seconds. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2176 is set, go to next step. If DTC P2176 is not set, problem is intermittent, system is OK. Check for poor connections or loose terminals at throttle actuator control module and PCM, then clean throttle body. Remove throttle body for cleaning. Be careful not to pinch fingers. (Scheme 23) Wipe off carbon deposits on throttle valve and inside throttle bore with a paper towel soaked in carburetor cleaner. Install throttle body. Go to step 6.
3. Turn ignition off. Disconnect air intake duct from throttle body. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu. Do the ETCS TEST in the INSPECTION menu. Watch throttle valve work. If the throttle valve operates to its full closed position, go to step 5. If the throttle valve does not operate to its full closed position, substitute a known-good throttle actuator control module. Go to step 6 and recheck.
4. Check for sludge or carbon on the throttle valve. If throttle valve is dirty, remove throttle body for cleaning. Be careful not to pinch fingers. (Scheme 23) Wipe off carbon deposits on throttle valve and inside throttle bore with a paper towel soaked in carburetor cleaner. Install throttle body. Go to step 6. If throttle valve is not dirty, go to 5
5. Turn ignition off. Replace throttle body.
6. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Turn ignition off. Turn ignition on, wait 10 seconds. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2176 is set, check for poor connections or loose terminals at throttle actuator control module and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.

DTC P2195 OR DTC P2197

Code Definition

1. DTC P2195: Rear Air Fuel Ratio Sensor Signal Stuck Lean (Bank 1, Sensor 1)
2. DTC P2197: Front Air Fuel Ratio Sensor Signal Stuck Lean (Bank 2, Sensor 1)

Note. This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Front A/F ratio sensor terminals will follow Rear (A/F) ratio sensor terminals and be enclosed in parantheses ( ).

1. Inspect condition of Air Fuel Ratio (A/F) sensor. If it is loose, go to next step. If it is not loose, problem is intermittent, system is OK. Check for poor connections or loose terminals at A/F sensor and PCM connector.
2. Turn ignition off. Reinstall A/F sensor.
3. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) .
4. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes.
5. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2195 and/or (P2197) are set, check for poor connections or loose terminals at A/F sensor and PCM harness connectors. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, go to next step.
6. Monitor the OBD STATUS for DTCs P2195 and/or (P2197) in the DTCs menu with the Honda PGM tester or the HDS. If it PASSED, troubleshooting is done. If it is FAILED, check for poor connections or loose terminals at A/F sensor and PCM harness connectors. Go to step 4 . If it is NOT COMPLETED, go to step 3 .

DTC P2199: INTAKE AIR TEMPERATURE SENSOR 1 & 2 CORRELATION

1. Turn ignition off. Disconnect both IAT sensors 1 & 2. Remove both sensors.
2. Cool both sensors to under 77°F (25°C).
3. Reconnect both IAT sensors to the 2-pin harness connectors. With the Honda PGM tester or the HDS connected to DLC, turn ignition on. Check IAT 1 sensor and IAT 2 sensor in the DATA list. If the difference between IAT 1 sensor and IAT 2 sensor is more than 45°F (25°C), go to next step. If the difference between IAT 1 sensor and IAT 2 sensor is not more than 45°F (25°C), problem is intermittent, system is OK at this time. Check for poor connection at IAT sensor 1 and/or 2 connector and the PCM connectors.
4. Turn ignition off. Replace the IAT sensor that has the largest difference from room temperature. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) .
5. Turn ignition off. Leave vehicle sit for more than 8 hours.
6. Start engine. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2199 is set, check for poor connections or loose terminals at IAT sensors 1 and/or 2 and PCM harness connectors. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, go to next step.
7. Monitor the OBD STATUS for DTC P2199 in the DTCs menu with the Honda PGM tester or the HDS. If it PASSED, troubleshooting is done. If it is FAILED, check for poor connections or loose terminals at IAT sensors 1 and/or 2 and PCM harness connectors. Go to step 1 . If it is NOT COMPLETED, go to step 5 .

DTC P2227: BAROMETRIC PRESSURE SENSOR, RANGE/PERFORMANCE PROBLEM

Note. Barometric Pressure (BARO) sensor us located inside PCM and is not available separately.

Note. If DTC P0107, P0108, P1128 and/or P1129 are stored at the same time as DTC P2227, troubleshoot these first, them recheck for DTC P2227.

1. Turn ignition on and wait 2 seconds. Using Honda PGM Tester or the HDS, check BARO sensor in the DATA list. If atmospheric pressure is measured, go to next step. If atmospheric pressure is not measured, Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If problem goes away with a known-good PCM, replace original PCM. Then repeat this step.
2. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle. Turn ignition off.
3. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). A/T in "D" position. Throttle position between 12-20° for 2 seconds.
4. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P2227 in the DTCs menu. If it FAILED, go to next step. If it is passed problem is intermittent, system is OK. If it is NOT COMPLETED, go to step 2 and recheck.
5. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2227 is set, check for poor connections or loose terminals at PCM harness connector. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P2228 OR DTC P2229

Code Definition

1. DTC P2228: Barometric Pressure Sensor Circuit Low Voltage
2. DTC P2229: Barometric Pressure Sensor Circuit High Voltage

Note. Barometric Pressure (BARO) sensor us located inside PCM and is not available separately.

1. Turn ignition on. Using Honda PGM Tester or the HDS, check BARO sensor in the DATA list. If BARO reading is 53 kPa or 1.58 volt or less, go to next step. If BARO reading is 53 kPa or 1.58 volt or less, problem is intermittent, system is OK at this time.
2. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2228 and/or P2229 are set, check for poor connections or loose terminals at PCM harness connector. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P2237 OR DTC P2240

Code Definition

1. DTC P2237: Rear Air Fuel Ratio Sensor IP Line High Voltage (Bank 1, Sensor 1)
2. DTC P2240: Front Air Fuel Ratio Sensor IP Line High Voltage (Bank 2, Sensor 1)

Note. This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear (A/F) ratio sensor terminals will precede Front A/F ratio sensor terminals. Also, Front A/F ratio sensor terminal information will be enclosed in parantheses ( ).

Note. If DTC P2237 and/or (P2240) is stored at the same time as DTC P0134 and/or (P0154), troubleshoot DTC P2237 and/or (P2240) first , then recheck for DTC P0134 and/or (P0154).

1. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2237 and/or (P2240) are set, go to next step. If DTCs P2237 and/or (P2240) are not set, problem is intermittent, system is OK. Check for poor connections or loose terminals at Air Fuel Ratio sensor and PCM connectors.
3. Turn ignition off. Disconnect A/F ratio sensor 8-pin connector. (Scheme 6) Disconnect PCM harness connector "A". (Scheme 4) Go to next step.
4. With a fused jumper wire, connect A/F ratio sensor 8-pin connector terminal No. 7 to ground. Check continuity between ground and PCM harness connector terminals A55 (A51). If there is continuity, go to next step. If there is no continuity, repair open in wire between A/F ratio sensor 8-pin connector and PCM. Go to step 8.
5. Remove the jumper wire from A/F ratio sensor connector and reconnect PCM harness connector "A". Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes.
6. Measure voltage between ground and A/F ratio sensor 8-pin connector terminal No. 7. If there is about 0.2 volt or less, go to step 12. If there is not about 0.2 volt or less, go to next step.
7. Replace A/F ratio sensor.
8. Reconnect PCM harness connector "A" and A/F ratio sensor 8-pin connector. Turn ignition on. Go to next step.
9. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
10. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2237 and/or (P2240) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTCs P2237 and/or (P2240) are not set, go to next step.
11. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P2237 and/or (P2240) in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If it is NOT COMPLETED, go to step 10 and recheck.
12. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2237 and/or (P2240) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P2238 OR DTC P2241

Code Definition

1. DTC P2238: Rear Air Fuel Ratio Sensor IP Line Low Voltage (Bank 1, Sensor 1)
2. DTC P2241: Front Air Fuel Ratio Sensor IP Line Low Voltage (Bank 2, Sensor 1)

Note. This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear (A/F) ratio sensor terminals will precede Front A/F ratio sensor terminals. Also, Front A/F ratio sensor terminal information will be enclosed in parantheses ( ).

1. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2238 and/or (P2241) are set, go to next step. If DTCs P2238 and/or (P2241) are not set, problem is intermittent, system is OK. Check for poor connections or loose terminals at Air Fuel Ratio sensor and PCM connectors.
3. Turn ignition off. Disconnect A/F ratio sensor 8-pin connector. (Scheme 6) Disconnect PCM harness connector "A". (Scheme 4) Go to next step.
4. Check continuity between ground and PCM harness connector terminals A55 (A51). If there is continuity, repair short in wire between A/F ratio sensor 8-pin connector and PCM. Go to step 8. If there is no continuity, go to next step.
5. Reconnect PCM harness connector "A". Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes.
6. Measure voltage between ground and A/F ratio sensor 8-pin connector terminal No. 7. If there is about 0.2 volt or less, go to step 12. If there is not about 0.2 volt or less, go to next step.
7. Replace A/F ratio sensor.
8. Reconnect PCM harness connector "A" and A/F ratio sensor 8-pin connector. Turn ignition on. Go to next step.
9. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
10. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2238 and/or (P2241) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTCs P2238 and/or (P2241) are not set, go to next step.
11. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P2238 and/or (P2241) in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If it is NOT COMPLETED, go to step 10 and recheck.
12. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs PP2238 and/or (P2241) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P2243 OR DTC P2247

Code Definition

1. DTC P2243: Rear Air Fuel Ratio Sensor VCENT Line High Voltage (Bank 1, Sensor 1)
2. DTC P2247: Front Air Fuel Ratio Sensor VCENT Line High Voltage (Bank 2, Sensor 1)

Note. This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear (A/F) ratio sensor terminals will precede Front A/F ratio sensor terminals. Also, Front A/F ratio sensor terminal information will be enclosed in parantheses ( ).

1. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2243 and/or (P2247) are set, go to next step. If DTCs P2243 and/or (P2247) are not set, problem is intermittent, system is OK. Check for poor connections or loose terminals at Air Fuel Ratio sensor and PCM connectors.
3. Turn ignition off. Disconnect A/F ratio sensor 8-pin connector. (Scheme 6) Disconnect PCM harness connector "A". (Scheme 4) Go to next step.
4. With a fused jumper wire, connect A/F ratio sensor 8-pin connector terminal No. 8 to ground. Check continuity between ground and PCM harness connector terminals A54 (A50). If there is continuity, repair open in wire between A/F ratio sensor 8-pin connector and PCM. Go to step 8. If there is no continuity, go to next step.
5. Remove the jumper wire from A/F ratio sensor connector and reconnect PCM harness connector "A". Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes.
6. Measure voltage between ground and A/F ratio sensor 8-pin connector terminal No. 8. If there is about 0.2 volt or less, go to step 12. If there is not about 0.2 volt or less, go to next step.
7. Replace A/F ratio sensor.
8. Reconnect PCM harness connector "A" and A/F ratio sensor 8-pin connector. Turn ignition on. Go to next step.
9. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
10. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2243 and/or (P2247) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTCs P2243 and/or (P2247) are not set, go to next step.
11. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P2243 and/or (P2247) in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If it is NOT COMPLETED, go to step 10 and recheck.
12. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2243 and/or (P2247) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P2245 OR DTC P2249

Code Definition

1. DTC P2245: Rear Air Fuel Ratio Sensor VCENT Line Low Voltage (Bank 1, Sensor 1)
2. DTC P2249: Front Air Fuel Ratio Sensor VCENT Line Low Voltage (Bank 2, Sensor 1)

Note. This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear (A/F) ratio sensor terminals will precede Front A/F ratio sensor terminals. Also, Front A/F ratio sensor terminal information will be enclosed in parantheses ( ).

1. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2245 and/or (P2249) are set, go to next step. If DTCs P2245 and/or (P2249) are not set, problem is intermittent, system is OK. Check for poor connections or loose terminals at Air Fuel Ratio sensor and PCM connectors.
3. Turn ignition off. Disconnect A/F ratio sensor 8-pin connector. (Scheme 6) Disconnect PCM harness connector "A". (Scheme 4) Go to next step.
4. Check continuity between ground and PCM harness connector terminals A54 (A50). If there is continuity, repair short in wire between A/F ratio sensor 8-pin connector and PCM. Go to step 8. If there is no continuity, go to next step.
5. Reconnect PCM harness connector "A". Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes.
6. Measure voltage between ground and A/F ratio sensor 8-pin connector terminal No. 8. If there is about 0.2 volt or less, go to step 12. If there is not about 0.2 volt or less, go to next step.
7. Replace A/F ratio sensor.
8. Reconnect PCM harness connector "A" and A/F ratio sensor 8-pin connector. Turn ignition on. Go to next step.
9. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
10. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2245 and/or (P2249) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTCs P2245 and/or (P2249) are not set, go to next step.
11. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P2245 and/or (P2249) in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If it is NOT COMPLETED, go to step 10 and recheck.
12. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2245 and/or (P2249) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P2251 OR DTC P2254

Code Definition

1. DTC P2251: Rear Air Fuel Ratio Sensor VS Line High Voltage (Bank 1, Sensor 1)
2. DTC P2254: Front Air Fuel Ratio Sensor VS Line High Voltage (Bank 2, Sensor 1)

Note. This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear (A/F) ratio sensor terminals will precede Front A/F ratio sensor terminals. Also, Front A/F ratio sensor terminal information will be enclosed in parantheses ( ).

Note. If DTC P2251 and/or (P2254) is stored at the same time as DTC P0134 and/or (P0154), troubleshoot DTC P2251 and/or (P2254) first , then recheck for DTC P0134 and/or (P0154).

1. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2251 and/or (P2254) are set, go to next step. If DTCs P2251 and/or (P2254) are not set, problem is intermittent, system is OK. Check for poor connections or loose terminals at Air Fuel Ratio sensor and PCM connectors.
3. Turn ignition off. Disconnect A/F ratio sensor 8-pin connector. (Scheme 6) Disconnect PCM harness connector "A". (Scheme 4) Go to next step.
4. With a fused jumper wire, connect A/F ratio sensor 8-pin connector terminal No. 6 to ground. Check continuity between ground and PCM harness connector terminals A53 (A49). If there is continuity, go to next step. If there is no continuity, repair open in wire between A/F ratio sensor 8-pin connector and PCM. Go to step 8.
5. Remove the jumper wire from A/F ratio sensor connector and reconnect PCM harness connector "A". Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes.
6. Measure voltage between ground and A/F ratio sensor 8-pin connector terminal No. 6. If there is about 0.2 volt or less, go to step 12. If there is not about 0.2 volt or less, go to next step.
7. Replace A/F ratio sensor.
8. Reconnect PCM harness connector "A" and A/F ratio sensor 8-pin connector. Turn ignition on. Go to next step.
9. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
10. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2251 and/or (P2254) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTCs P2251 and/or (P2254) are not set, go to next step.
11. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P2251 and/or (P2254) in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If it is NOT COMPLETED, go to step 10 and recheck.
12. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2251 and/or (P2254) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P2252 OR DTC P2255

Code Definition

1. DTC P2252: Rear Air Fuel Ratio Sensor VS Line Low Voltage (Bank 1, Sensor 1)
2. DTC P2255: Front Air Fuel Ratio Sensor VS Line Low Voltage (Bank 2, Sensor 1)

Note. This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear (A/F) ratio sensor terminals will precede Front A/F ratio sensor terminals. Also, Front A/F ratio sensor terminal information will be enclosed in parantheses ( ).

1. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2252 and/or (P2255) are set, go to next step. If DTCs P2252 and/or (P2255) are not set, problem is intermittent, system is OK. Check for poor connections or loose terminals at Air Fuel Ratio sensor and PCM connectors.
3. Turn ignition off. Disconnect A/F ratio sensor 8-pin connector. (Scheme 6) Disconnect PCM harness connector "A". (Scheme 4) Go to next step.
4. Check continuity between ground and PCM harness connector terminals A53 (A49). If there is continuity, repair short in wire between A/F ratio sensor 8-pin connector and PCM. Go to step 8. If there is no continuity, go to next step.
5. Reconnect PCM harness connector "A". Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes.
6. Measure voltage between ground and A/F ratio sensor 8-pin connector terminal No. 6. If there is about 0.2 volt or less, go to step 12. If there is not about 0.2 volt or less, go to next step.
7. Replace A/F ratio sensor.
8. Reconnect PCM harness connector "A" and A/F ratio sensor 8-pin connector. Turn ignition on. Go to next step.
9. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
10. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2252 and/or (P2255) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTCs P2252 and/or (P2255) are not set, go to next step.
11. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P2252 and/or (P2255) in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If it is NOT COMPLETED, go to step 10 and recheck.
12. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2252 and/or (P2255) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P2279: INTAKE AIR SYSTEM LEAK

Note. If DTC P0443 is stored at the same time as DTC P2279, troubleshoot DTC P0443 first, then recheck for DTC P2279.

1. Check for vacuum leaks from the following parts: PCV valve. PCV hose. Purge (PCS) line. Throttle body. Brake booster hose. Engine mount control solenoid valve.
2. If they are OK, go to next step. If they are not OK, repair or replace damaged parts as necessary. Go to step 5 .
3. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes.
4. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P2279 in the DTCs menu. If it is PASSED, problem is intermittent, system is OK at this time. If it is NOT COMPLETED, go to step 3 and recheck.
5. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Go to next step.
6. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes.
7. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2279 is set, check for vacuum leaks at PCV valve and hose, PCS line, throttle body and brake booster hose. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, go to the indicated DTC and troubleshoot.
8. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P2279 in the DTCs menu. If it is PASSED, troubleshooting is done. If it is FAILED, go to step 1 and recheck. If it is NOT COMPLETED, go to step 6 and recheck.

DTC P2413: EGR SYSTEM MALFUNCTION

Note. If DTC P0651 is set at the same time as DTC P2413, troubleshoot DTC P0651 first, then recheck for P2413.

1. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Turn ignition on. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle.
2. Do the EGR test in the INSPECTION menu. If the EGR system is OK, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at EGR valve and PCM connectors. If EGR system is not OK, go to next step.
3. Check the result in the display of the Honda PGM tester or the HDS. If it displays "System is Failure", go to next step. If it does not display "System is Failure". Go to step 16.
4. With the Honda PGM tester or the HDS, check the EGR VLS in the DATA list. If there is about 0 volt, go to next step. If there is not about 0 volt, go to step 16.
5. Disconnect EGR valve 6-pin connector. (Scheme 25) Turn ignition on. Measure voltage between ground and EGR valve 6-pin connector terminal No. 3 (Yellow/Blue wire). If there is about 5 volts, go to step 7. If there is not about 5 volt, go to next step.
6. Turn ignition off.
7. Disconnect PCM harness connector "A". (Scheme 4) Check for continuity between PCM harness connector terminal A27 and EGR valve 6-pin connector terminal No. 3 (Yellow/Blue wire). If there is continuity, go to step 33. If there is no continuity, repair open in wire between PCM harness connector terminal A27 and EGR valve 6-pin connector terminal No. 3 (Yellow/Blue wire). Go to step 28.
8. Turn ignition off. Disconnect PCM harness connector "A". Check for continuity between ground and EGR valve 6-pin connector terminal No. 1 (White/Black wire). If there is continuity, repair short in wire between PCM harness connector terminal A42 EGR valve 6-pin connector terminal No. 1. If there is no continuity, go to next step.
9. Check for continuity between PCM harness connector terminal A42 and EGR valve 6-pin connector terminal No. 1 (White/Black wire). If there is continuity, go to step 17. If there is no continuity, repair open in wire between PCM harness connector terminal A42 and EGR valve 6-pin connector terminal No. 1 (White/Black wire).
10. Turn ignition off. Disconnect EGR valve 6-pin connector.
11. Disconnect PCM harness connector "A". Check for continuity between ground and EGR valve 6-pin connector terminal No. 4 (Blue/Red wire). If there is continuity, repair short in wire between PCM harness connector terminal A15 and EGR valve 6-pin connector terminal No. 4 (Blue/Red wire). If there is no continuity, go to next step.
12. Check for continuity between PCM harness connector terminal A15 and EGR valve 6-pin connector terminal No. 4 (Blue/Red wire). If there is continuity, go to next step. If there is no continuity, repair open in wire between PCM harness connector terminal A15 and EGR valve 6-pin connector terminal No. 4 (Blue/Red wire). Go to step 28.
13. Check continuity between ground and EGR valve 6-pin connector terminal No. 6 (Black wire). If there is continuity, go to next step. If there is no continuity, repair open in wire between EGR valve 6-pin connector terminal No. 6 (Black wire) and ground connector G101. Go to step 28.
14. Reconnect PCM harness connector "A".
15. With a fused jumper wire, connect battery positive to EGR valve 6-pin connector terminal No. 4. Start engine and let it idle. Connect another jumper wire to EGR valve 6-pin connector terminal No. 6 and touch jumper to battery negative terminal. If engine stalls or runs rough, go to step 33. If engine does not stall or run rough, go to step 19.
16. Turn ignition off. Disconnect EGR valve 6-pin connector.
17. At the sensor side, measure resistance between EGR valve 6-pin connector terminal No. 1 and 2. If there is resistance of 100K ohms or more, go to step 27. If there is no resistance, go to next step.
18. At the sensor side, measure resistance between EGR valve 6-pin connector terminal No. 1 and 3. If there is resistance of 100K ohms or more, go to step 27. If there is no resistance, go to next step.
19. Remove EGR valve and EGR plate.
20. Clean the intake manifold EGR port with carburetor cleaner. Also clean the passage inside EGR valve with carburetor cleaner. Install EGR valve and EGR plate.
21. Reconnect PCM harness connector "A".
22. Reconnect EGR valve 6-pin connector.
23. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
24. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle.
25. With the Honda PGM tester or the HDS, do the EGR test in the INSPECTION menu. If the EGR system is OK, go to step 30. If EGR system is not OK, go to next step.
26. Turn ignition off.
27. Replace the EGR valve.
28. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
29. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle.
30. Test drive vehicle under no load condition for about 10 minutes. Try to keep engine speed within 1700-2500 RPM range.
31. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2413 is set, check for poor connections or loose terminals at EGR valve and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, go to next step.
32. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P2422 in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED. Go to step 1 and recheck. If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION, go to step 29 and recheck.
33. Update the PCM if it does not have the latest software, or substitute a known-good PCM.
34. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes.
35. Test drive vehicle under no load condition for about 10 minutes. Try to keep engine speed within 1700-2500 RPM range.
36. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2413 is set, check for poor connections or loose terminals at EGR valve and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

Scheme 25

DTC P2422: EVAP CANISTER VENT SHUT VALVE, CLOSE MALFUNCTION

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Open fuel fill cap for 5 seconds, then tighten it.
3. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle.
4. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P2422 in the DTCs menu. If it is PASSED, problem is intermittent, system is OK at this time. If it FAILED, go to next step.
5. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
6. Remove EVAP canister vent shut valve. Connect 2-pin connector to EVAP canister vent shut valve.
7. Using the Honda PGM Tester or the HDS, do the EVAP CVS ON in the INSPECTION menu.
8. Check EVAP canister vent shut valve operation. If the valve is operating, check for blockage in the EVAP canister. Go to step 11 . If the valve is not operating, go to next step.
9. Turn ignition off.
10. Replace EVAP canister vent shut valve.
11. Turn ignition on.
12. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure) . Go to next step.
13. Turn ignition off.
14. Open fuel fill cap for 5 seconds, then tighten it.
15. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle.
16. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2422 is set, check for poor connections or loose terminals at FTP sensor, EVAP canister vent shut valve and PCM harness connector. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, go to next step.
17. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P2422 in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED, check for poor connections or loose terminals at FTP sensor, EVAP canister vent shut valve and PCM harness connector. Go to step 1 . If it is NOT COMPLETED, go to step 12 and recheck.

DTC P2552: THROTTLE ACTUATOR CONTROL MODULE RELAY MALFUNCTION

1. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the ETCS test in the INSPECTION menu. If the ETCS is OK, Problem is intermittent, system is OK. Check for poor connections or loose terminals at throttle actuator control module and PCM harness connector. If the ETCS is not OK, go to next step.
2. Turn ignition off. Disconnect throttle actuator control module 16-pin connector. Disconnect PCM harness connector "A". (Scheme 4) Go to next step.
3. Turn ignition on. Measure voltage between ground and PCM harness connector terminal A2 (Green wire). If there is battery voltage, go to next step. If there is not battery voltage, repair short in wire between PCM harness connector terminal A2 and throttle actuator control module. Go to step 5.
4. Turn ignition off. Replace throttle body. go to next step.
5. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2552 is set, check for poor connections or loose terminals at throttle body and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, troubleshooting is complete.

DTC P2610: 24-HOUR TIMER MALFUNCTION

1. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2610 is set, update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If problem goes away with substitute PCM, replace original PCM. If DTC P2610 is not set, problem is intermittent, system is OK at this time.

DTC P2627 OR DTC P2630

Code Definition

1. DTC P2627: Rear Air Fuel Ratio Sensor Label Circuit Low Voltage (Bank 1, Sensor 1)
2. DTC P2630: Front Air Fuel Ratio Sensor Label Circuit Low Voltage (Bank 2, Sensor 1)

Note. This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear (A/F) ratio sensor terminals will precede Front A/F ratio sensor terminals. Also, Front A/F ratio sensor terminal information will be enclosed in parantheses ( ).

1. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P0107, P0112, P0117, P2122, P2127, P2228, P0452, P0700, P2627 and/or (P2630) are set, go to step 7. If DTCs P0107, P0112, P0117, P2122, P2127, P2228, P0452, P0700, P2627 and/or (P2630) are not set, go to next step.
3. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2627 and/or (P2630) are set, go to next step. If DTCs P2627 and/or (P2630) are not set, problem is intermittent, system is OK. Check for poor connections or loose terminals at Air Fuel Ratio sensor and PCM connectors.
4. Turn ignition off. Disconnect PCM harness connector "A". (Scheme 4) Go to next step.
5. Check continuity between ground and PCM harness connector terminals A56 (A52). If there is continuity, go to next step. If there is no continuity, go to step 13.
6. Disconnect A/F ratio sensor 8-pin connector. (Scheme 6) Check continuity between ground and PCM harness connector terminals A56 (A52). If there is continuity, go to next step. If there is no continuity, go to step 9.
7. Turn ignition off. Remove A/F ratio sensor relay. Disconnect the following connectors: ELD unit. Engine mount control solenoid valve. Front and Rear A/F sensors, (Sensor 1). Front and Rear Heated Oxygen sensors, (Sensor 2). EVAP canister vent shut valve. EVAP bypass solenoid valve.
8. Check for continuity between ground and A/F ratio sensor relay connector terminal No. 2. If there is continuity, repair short in wire between A/F sensor relay and each connector in the list above. Go to step 10. If there is no continuity, go to step 13.
9. Replace A/F ratio sensor.
10. Reconnect each disconnected sensor. Replace A/F sensor relay. Go to next step.
11. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
12. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2627 and/or (P2630) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTCs P2627 and/or (P2630) are not set, troubleshooting is done.
13. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2627 and/or (P2630) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P2628 OR DTC P2631

Code Definition

1. DTC P2628: Rear Air Fuel Ratio Sensor Label Circuit High Voltage (Bank 1, Sensor 1)
2. DTC P2631: Front Air Fuel Ratio Sensor Label Circuit High Voltage (Bank 2, Sensor 1)

Note. This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear (A/F) ratio sensor terminals will precede Front A/F ratio sensor terminals. Also, Front A/F ratio sensor terminal information will be enclosed in parantheses ( ).

1. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2628 and/or (P2631) are set, go to next step. If DTCs P2628 and/or (P2631) are not set, problem is intermittent, system is OK. Check for poor connections or loose terminals at Air Fuel Ratio sensor and PCM connectors.
3. Turn ignition off. Disconnect A/F ratio sensor 8-pin connector. (Scheme 6) Disconnect PCM harness connector "A". (Scheme 4) Go to next step.
4. With a fused jumper wire, connect A/F ratio sensor 8-pin connector terminal No. 4 to ground. Check continuity between ground and PCM harness connector terminals A56 (A52). If there is continuity, go to next step. If there is no continuity, repair open in wire between A/F ratio sensor 8-pin connector and PCM. Go to step 8.
5. Remove the jumper wire from A/F ratio sensor connector and reconnect PCM harness connector "A". Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes.
6. Measure voltage between ground and A/F ratio sensor 8-pin connector terminal No. 4. If there is about 0.2 volt or less, go to step 11. If there is not about 0.2 volt or less, go to next step.
7. Replace A/F ratio sensor.
8. Reconnect PCM harness connector "A" and A/F ratio sensor 8-pin connector. Go to next step.
9. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure). Go to next step.
10. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2628 and/or (P2631) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTCs P2628 and/or (P2631) are not set, troubleshooting is done.
11. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle for 2 minutes. Check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2628 and/or (P2631) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

DTC P2A00 OR DTC P2A03

Code Definition

1. DTC P2A00: Rear Air Fuel Ratio Sensor Range/Performance Problem (Bank 1, Sensor 1)
2. DTC P2A03: Front Air Fuel Ratio Sensor Range/Performance Problem (Bank 2, Sensor 1)

Note. This test covers both Front and Rear Air Fuel Ratio (A/F) sensors. The information will be shown Rear (Bank 1) first and Front (Bank 2) second. When discussion of PCM harness connector terminals arises, Rear (A/F) ratio sensor terminals will precede Front A/F ratio sensor terminals. Also, Front A/F ratio sensor terminal information will be enclosed in parentheses ( ).

1. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle.
2. Using Honda PGM Tester or the HDS, check AF FB AVE (LT FUEL TRIM) in the DATA list. If the value measured is 0.8-1.2, go to next step. If the value measured is not 0.8-1.2, go to next step 1 and recheck.
3. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). A/T in "D" position. Vehicle speed at 30 MPH or more and engine speed at 2300 RPM or less. Drive with throttle fully opened for 5 seconds from an engine speed of 1600 RPM, then decelerate with the throttle fully closed.
4. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P2A00 and/or (P2A03) in the DTCs menu. If it FAILED, go to next step. If it is passed problem is intermittent, system is OK. If it is EXECUTING, keep driving until the results come on. If it is OUT OF CONDITION, go to step 1 and recheck.
5. Turn ignition off. Replace A/F ratio sensor. Go to next step
6. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu. Start engine. Hold engine at 3000 RPM with no load in (Park or Neutral) until the radiator fan comes on, then let engine idle.
7. Using Honda PGM Tester or the HDS, check AF FB AVE (LT FUEL TRIM) in the DATA list. If the value measured is 0.8-1.2, go to next step. If the value measured is not 0.8-1.2, go to next step 6 and recheck.
8. Test drive vehicle under the following conditions: Engine coolant temperature more than 158°F (70°C). A/T in "D" position. Vehicle speed at 30 MPH or more and engine speed at 2300 RPM or less. Drive with throttle fully opened for 5 seconds from an engine speed of 1600 RPM, then decelerate with the throttle fully closed.
9. Using Honda PGM Tester or the HDS, check for Temporary DTCs or DTCs in the DTC menu. If DTCs P2A00 and/or (P2A03) are set, check for poor connections or loose terminals at A/F ratio sensor and PCM harness connector. Go to step 1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTCs P2A00 and/or (P2A03) are not set, go to next step.
10. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTCs P2A00 and/or (P2A03) in the DTCs menu. If it FAILED, go to next step. If it is passed problem is intermittent, system is OK. If it is EXECUTING, keep driving until the results come on. If it is OUT OF CONDITION, go to step 6 and recheck.

DTC P2646: VTEC OIL PRESSURE SWITCH CIRCUIT, LOW VOLTAGE

Special tools required

1. Pressure Gauge Adapter (07NAJ-P07010A)
2. A/T Low Pressure Gauge With Panel (07406-0070300)
3. A/T Pressure Hose (07406-0020201)
4. A/T Pressure Hose, 2210 mm (07MAJ-PY4011A)
5. A/T Pressure Adapter (07MAJ-PY40120)
6. Oil Pressure Hose (07ZAJ-S5AA200)

1. Check engine oil level. If oil level is OK, go to next step. If oil level is low, adjust engine oil level to proper level. Go to step 11.
2. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
3. Using Honda PGM Tester or the HDS, do the VTEC TEST in the INSPECTION menu. If VTEC system is OK, problem is intermittent, system is OK. Check for poor connections or loose terminals at VTEC oil pressure switch or VTEC solenoid valve and at PCM. If VTEC system is not OK, go to next step.
4. Turn ignition off. Disconnect VTEC oil pressure switch 2-pin connector. Go to next step.
5. Turn ignition on. Using Honda PGM Tester or the HDS, check the VTEC in the DATA list. If the VTEC oil pressure switch is ON, go to next step. If the VTEC oil pressure switch is not ON, go to step 7.
6. Turn ignition off. Remove VTEC oil pressure switch. Install Adapter (07NAJ-P07010A), Hose (07MAJ-PY40120) and Gauge (07406-0070300). (Scheme 26) Reinstall VTEC oil pressure switch. Reconnect VTEC solenoid valve single pin harness connector and VTEC oil pressure switch 2-pin harness connector. Start engine and run at 3000 RPM with no load (in park or neutral) until radiator fan comes on. Connect remote tachometer under hood. Check oil pressure at 1000, 2000 and 3000 RPM. Checks should be done in under one minute because of engine running with no load. If oil pressure is less than 49 kPa, go to next step. If oil pressure is not as specified, test VTEC solenoid valve. See «RELAYS & SOLENOIDS»(ref-11829-S14356084932000113000000) in SYSTEM & COMPONENT TESTING article.
7. Using Honda PGM Tester or the HDS, do the VTEC TEST in the INSPECTION menu. If oil pressure is below 7 psi (49 kPa), inspect VTEC oil line. If line is OK, replace VTEC solenoid valve. Go to step 11. If oil pressure is not below 7 psi (49 kPa). Go to step 11.
8. Turn ignition off. Disconnect VTEC oil pressure switch 2-pin connector. Disconnect PCM harness connector "A". (Scheme 4)
9. Check for continuity between ground and PCM harness connector terminal A43 (Blue/Black wire). If there is continuity, repair short in wire between PCM harness connector terminal A43 (Blue/Black wire) and VTEC oil pressure switch 2-pin connector. If there is no continuity, go to step 15.
10. Reconnect VTEC oil pressure switch. Re connect PCM harness connector "A".
11. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
12. Test drive vehicle under the following conditions: Accelerate with A/T in 1st position to an engine speed over 4000 RPM. Hold speed for at least 2 seconds.
13. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2646 is set, check for poor connections or loose terminals at VTEC oil pressure switch, VTEC solenoid valve and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, go to next step.
14. Monitor the OBD STATUS for DTC P2646 in the DTCs menu with the Honda PGM tester or the HDS. If it PASSED, troubleshooting is complete. If it is FAILED. Go to step 1 and recheck. If it is NOT COMPLETED, go to step 12 and recheck.
15. Update the PCM if it does not have the latest software, or substitute a know-good PCM. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
16. Test drive vehicle under the following conditions: Accelerate with A/T in 1st position to an engine speed over 4000 RPM. Hold speed for at least 2 seconds.
17. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2646 is set, check for poor connections or loose terminals at VTEC oil pressure switch, VTEC solenoid valve and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, PCM was updated, troubleshooting is done. If PCM was substituted, replace original PCM.

Scheme 26

DTC P2647: VTEC OIL PRESSURE SWITCH CIRCUIT, HIGH VOLTAGE

1. Check engine oil level. If oil level is OK, go to next step. If oil level is low, adjust engine oil level to proper level. Go to step 8.
2. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
3. Using Honda PGM Tester or the HDS, do the VTEC TEST in the INSPECTION menu. If VTEC system is OK, problem is intermittent, system is OK. Check for poor connections or loose terminals at VTEC oil pressure switch and at PCM. If VTEC system is not OK, go to next step.
4. Check the result on display. If it is indicating POSSIBLE PROBLEM, check for poor connections or loose terminals at VTEC oil pressure switch. If it is OK, then replace VTEC solenoid valve. Go to step 9. If it is not indicating POSSIBLE PROBLEM, go to next step.
5. Turn ignition off. Disconnect VTEC oil pressure switch 2-pin connector. Check for continuity between ground and VTEC oil pressure switch 2-pin connector terminal No. 2 (Brown/Yellow wire). If there is continuity, go to next step. If there is no continuity, repair open in wire between VTEC oil pressure switch 2-pin connector terminal No. 2 and ground connector G101. Go to step 8.
6. Disconnect PCM harness connector "A". (Scheme 4) With a fused jumper wire, connect VTEC oil pressure switch 2-pin connector terminal No. 1 (Blue/Black wire) to ground. Check for continuity between ground and PCM harness connector terminal A43. If there is continuity, go to step 12. If there is no continuity, repair open in wire between PCM harness connector terminal A43 and VTEC oil pressure switch 2-pin connector terminal No. 1 (Blue/Black wire). Go to next step.
7. Reconnect PCM harness connector "A".
8. Reconnect VTEC oil pressure switch 2-pin connector.
9. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
10. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2647 is set, check for poor connections or loose terminals at VTEC oil pressure switch and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTC P2647 is not set, go to next step.
11. Monitor the OBD STATUS for DTC P2647 in the DTCs menu with the Honda PGM tester or the HDS. If it PASSED, troubleshooting is complete. If it is FAILED. Go to step 1 and recheck. If it is NOT COMPLETED, go to step 10 and recheck.
12. Update the PCM if it does not have the latest software, or substitute a know-good PCM. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
13. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2647 is set, check for poor connections or loose terminals at VTEC oil pressure switch and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTC P2647 is not set, PCM was updated, troubleshooting is done. If PCM was substituted, replace original PCM.

Scheme 27

DTC P2648: VTEC SOLENOID VALVE CIRCUIT, LOW VOLTAGE

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Using Honda PGM Tester or the HDS, do the VTEC TEST in the INSPECTION menu. If VTEC system is OK, problem is intermittent, system is OK. Check for poor connections or loose terminals at VTEC solenoid valve and at PCM. If VTEC system is not OK, go to next step.
3. Turn ignition off. Disconnect VTEC solenoid valve 1-pin connector. Measure resistance between solenoid valve body and VTEC solenoid valve 2-pin connector terminal No. 1. If the resistance is 14-30 ohms, go to next step. If the resistance is not 14-30 ohms, replace VTEC solenoid valve. Go to step 5.
4. Disconnect PCM harness connector "A". (Scheme 4) Check for continuity between ground and PCM harness connector terminal A17. If there is continuity, repair short in wire between PCM harness connector terminal A17 and VTEC solenoid valve. Go to next step. If there is no continuity, go to step 10.
5. Reconnect PCM harness connector "A". Reconnect VTEC solenoid valve 1-pin connector. Go to next step.
6. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
7. Test drive vehicle under the following conditions: Accelerate with A/T in 1st position to an engine speed over 4000 RPM. Hold speed for at least 2 seconds.
8. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2648 is set, check for poor connections or loose terminals at VTEC solenoid valve and PCM harness connectors. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If Temporary DTCs or DTCs are not set, go to next step.
9. Monitor the OBD STATUS for DTC P2648 in the DTCs menu with the Honda PGM tester or the HDS. If it PASSED, troubleshooting is complete. If it is FAILED. Go to step 1 and recheck. If it is NOT COMPLETED, go to step 7 and recheck.
10. Update the PCM if it does not have the latest software, or substitute a know-good PCM. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
11. Test drive vehicle under the following conditions: Accelerate with A/T in 1st position to an engine speed over 4000 RPM. Hold speed for at least 2 seconds.
12. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2648 is set, check for poor connections or loose terminals at VTEC solenoid valve and PCM harness connector. Go to 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTC P2648 is not set, PCM was updated, troubleshooting is done. If PCM was substituted, replace original PCM.

DTC P2649: VTEC SOLENOID VALVE CIRCUIT, HIGH VOLTAGE

1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
2. Start engine. Hold engine speed at 3000 RPM with no load (A/T in Park or Neutral) until radiator fan comes on. Then let engine idle.
3. Using Honda PGM Tester or the HDS, check for DTCs in the DTC menu. If DTC P2649 is set, go to next step. If DTC P2649 is not set, problem is intermittent, system is OK. Check for poor connections or loose terminals at VTEC solenoid valve and PCM connectors.
4. Turn ignition off. Disconnect VTEC solenoid valve 1-pin connector. Measure resistance between solenoid valve body and VTEC solenoid valve 2-pin connector terminal No. 1. If the resistance is 14-30 ohms, go to next step. If the resistance is not 14-30 ohms, replace VTEC solenoid valve. Go to step 7.
5. Disconnect PCM harness connector "A". (Scheme 4) With a fused jumper wire connect VTEC solenoid valve 1-pin connector to ground. Check for continuity between ground and PCM harness connector terminal A17. If there is continuity, go to step 13. If there is no continuity, repair open in wire between PCM harness connector terminal A17 and VTEC solenoid valve. Go to next step.
6. Reconnect PCM harness connector "A".
7. Reconnect VTEC solenoid valve 1-pin connector.
8. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
9. Start engine. Hold engine speed at 3000 RPM with no load (A/T in Park or Neutral) until radiator fan comes on. Then let engine idle.
10. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2649 is set, check for poor connections or loose terminals at VTEC solenoid valve and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTC P2649 is not set, go to step 12.
11. Monitor the OBD STATUS for DTC P2649 in the DTCs menu with the Honda PGM tester or the HDS. If it PASSED, troubleshooting is complete. If it is FAILED. Go to step 1 and recheck. If it is NOT COMPLETED, go to step 10 and recheck.
12. Update the PCM if it does not have the latest software, or substitute a know-good PCM.
13. Do the PCM idle learn procedure. See «PCM IDLE LEARN PROCEDURE»(/acura/mdx/i-2000-2006/remont/testing-diagnostics/#engine-performance-system-self-diagnostics__pcm-idle-learn-procedure).
14. Start engine. Hold engine speed at 3000 RPM with no load (A/T in Park or Neutral) until radiator fan comes on. Then let engine idle.
15. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P2649 is set, check for poor connections or loose terminals at VTEC solenoid valve and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If DTC P2649 is not set, PCM was updated, troubleshooting is done. If PCM was substituted, replace original PCM.

DTC U0107: LOST COMMUNICATION WITH THROTTLE ACTUATOR CONTROL MODULE

1. Turn ignition on. With the Honda PGM tester or the HDS, do DTC CLEAR in the CLEAR menu.
2. Check for Temporary DTCs or DTCs in the DTC menu. If DTC U0107 is set, go to next step. If DTC U0107 is not set, go to step 5.
3. Turn ignition off within 2 seconds after using he Honda PGM tester or the HDS and doing DTC CLEAR in the CLEAR menu. If the DTC U0107 is stored, do the DTC CLEAR again.
4. Disconnect intake air duct from throttle body. Press and hold accelerator pedal fully down. Turn ignition on. Check throttle valve operation. If the throttle valve fully closes, then fully opens, go to step 7. If the throttle valve does not fully close after ignition is on. Go to step 9. If throttle valve closes fully, but then does not fully open, go to step 15.
5. Start engine. Check for Temporary DTCs or DTCs in the DTC menu. If DTC U0107 is set, go to next step. If DTC U0107 did not set, problem is intermittent, system is OK. Check for poor connections or loose terminals at, throttle actuator control module relay, the ETC fuse (15- amp) at under-hood sub-fuse box and PCM harness connector.
6. Turn ignition off. Disconnect PCM harness connector "A". (Scheme 4) Check continuity between ground and PCM harness connector terminals A39 and A40. If there is continuity, go to step 22. If there is not continuity, repair open in wire between ground connector G101 and PCM harness connector terminals A39 and A40. Go to step 20.
7. Turn ignition off. Disconnect PCM harness connector "A". Disconnect throttle actuator control module 16-pin connector. Check continuity between ground and throttle actuator control module 16-pin connector terminal No. 4 (Blue wire). If there is continuity, repair short in wire between PCM and throttle actuator control module 16-pin connector terminal No. 4. If there is not continuity. Go to next step.
8. Check continuity between PCM harness connector terminal A1 (Blue wire) and throttle actuator control module 16-pin connector terminal No. 4. If there is continuity, go to step 19. If there is not continuity, repair open in wire between PCM harness connector terminal A1 (Blue wire) and throttle actuator control module 16-pin connector terminal No. 4. Go to step 20
9. Turn ignition off. Disconnect throttle actuator control module 16-pin connector. Check continuity between ground and throttle actuator control module 16-pin connector terminal No. 2 (Black wire) and No. 10 (Black wire) individually. If there is continuity, go to step 13. If there is not continuity, repair open in wire between ground connector G101. Go to step 20.
10. Using he Honda PGM tester or the HDS, check the TAC RELAY in the DATA list. If it is on, go to step 22. If it is not on, go to next step.
11. Turn ignition off. With the throttle actuator control module 16-pin connector still disconnected, turn ignition on. Measure voltage between ground and throttle actuator control module 16-pin connector terminal No. 6 (Green/White wire). If there is about 3 volts or more, go to next step. If there is not about 3 volts or more, go to step 17.
12. Measure voltage between ground and throttle actuator control module 16-pin connector terminal No. 1 (Yellow/Green wire). If there is battery voltage, go to step 19. If there is not battery voltage, go to next step.
13. Measure voltage between ground and throttle actuator control relay connector terminal No. 1. If there is battery voltage, go to next step. If there is not battery voltage, check the ETC fuse (15- amp) at under-hood sub-fuse box. If fuse is OK, then check for an open in wire between under-hood sub-fuse box and throttle actuator control relay. Go to step 21.
14. Turn ignition off. Remove throttle actuator control relay. Disconnect throttle actuator control module 16-pin connector. Connect throttle actuator control relay connector terminal No. 2 to ground with a fused jumper wire. Check for continuity between ground and throttle actuator control relay connector terminal No. 1. If there is continuity, replace throttle actuator control relay. Go to step 19. If there is not continuity, repair wire between throttle actuator control module and throttle actuator control relay. Go to step 19.
15. Turn ignition off. Disconnect PCM harness connector "A". Check for continuity between ground and throttle actuator control module 16-pin connector terminal No. 13. If there is continuity, repair wire between PCM and throttle actuator control module Go to step 19. If there is not continuity, go to next step.
16. Check continuity between PCM harness connector terminal A2 (Green wire) and throttle actuator control module 16-pin connector terminal No. 13. If there is continuity, go to step 19. If there is not continuity, repair open in wire between PCM harness connector terminal A2 (Green wire) and throttle actuator control module 16-pin connector terminal No. 13. Go to step 20.
17. Turn ignition off. Disconnect PCM harness connector "A". Disconnect throttle actuator control module 16-pin connector. Check for continuity between ground and throttle actuator control module 16-pin connector terminal No. 6. If there is continuity, repair wire between PCM harness connector terminal A29 and throttle actuator control module Go to step 20.
18. Check continuity between PCM harness connector terminal A29 (Green/White wire) and throttle actuator control module 16-pin connector terminal No. 6. If there is continuity, go to step 22. If there is not continuity, repair open in wire between PCM harness connector terminal A29 (Green/White wire) and throttle actuator control module 16-pin connector terminal No. 6. Go to step 20.
19. Replace throttle body assembly.
20. Turn ignition on.
21. Turn ignition on. With the Honda PGM tester or the HDS, do DTC CLEAR in the CLEAR menu. Check for Temporary DTCs or DTCs in the DTC menu. If any Temporary DTCs or DTCs are set, go to next step. If no Temporary DTCs or DTCs are set, troubleshooting is done.
22. Update the PCM if it does not have the latest software, or substitute a known-good PCM. Check for Temporary DTCs or DTCs in the DTC menu. If DTC U0107, check for poor connections or loose terminals at throttle actuator control module and PCM harness connector. Go to step 1. If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, PCM was updated, troubleshooting is complete. If PCM was substituted, replace original PCM.

Float Test

Ensure fuel tank is less than half full. Remove fuel filler cap to relieve fuel tank pressure, then reinstall cap. Disconnect fuel tank vapor recirculation tube. (Scheme 28) Connect a vacuum pump to vapor recirculation hose coming from fuel tank. Plug tube. Apply vacuum to fuel tank vapor recirculation hose. If vacuum holds, replace fuel tank vapor control valve. See EMISSION SYSTEMS & SUB-SYSTEMS in REMOVAL & INSTALLATION article. If vacuum does not hold, float is okay. Perform valve test. See VALVE TEST.

Scheme 28

Valve Test

1. Ensure fuel tank is less than half full. Remove fuel filler cap. Disconnect fuel tank vapor signal hose. (Scheme 29) Disconnect vacuum hose from EVAP canister, then plug ports with plugs. Connect vacuum pump/gauge to EVAP canister vent shut valve port. (Scheme 30) Apply vacuum with vacuum pump/gauge (80 pumps). If vacuum holds, go to next step. If vacuum does not hold, go to step 3.
2. Connect a second vacuum pump to fuel tank vapor signal tube. (Scheme 29) Apply vacuum with vacuum pump (1 pump). Check vacuum reading at vacuum pump/gauge used in step 1). If vacuum holds, replace fuel tank vapor control valve. See «EMISSION SYSTEMS & SUB-SYSTEMS»(/acura/mdx/i-2000-2006/remont/removal-installation/#engine-controls-removal-installation) in REMOVAL & INSTALLATION article. If vacuum is released, fuel tank vapor control valve is okay. Go to step 4.
3. Disconnect fuel tank vapor quick-connect fitting from EVAP canister. Cap port on canister. Reapply 80 pumps of vacuum with vacuum pump. If vacuum holds, replace fuel tank vapor control valve. See «EMISSION SYSTEMS & SUB-SYSTEMS»(/acura/mdx/i-2000-2006/remont/removal-installation/#engine-controls-removal-installation) in REMOVAL & INSTALLATION article. If vacuum does not hold, check EVAP canister vent shut valve "O" ring. If "O" ring is okay, replace EVAP canister and go back to step 1.
4. Fill fuel tank with fuel. Check for fuel in hoses at 2-way valve and fuel tank vapor recirculation hose. (Scheme 31) If fuel runs out of hoses at either location, replace fuel tank vapor control valve. See «EMISSION SYSTEMS & SUB-SYSTEMS»(/acura/mdx/i-2000-2006/remont/removal-installation/#engine-controls-removal-installation) in REMOVAL & INSTALLATION article. If fuel does not run out at either location, the fuel tank vapor system is operating normally. NOTE: Tiny droplets of fuel at either location is normal.

Scheme 29

Scheme 30

Scheme 31

EVAPORATIVE EMISSION 2-WAY VALVE TEST

1. Remove fuel filler cap. Remove vapor hose from EVAP 2-way valve. Connect "T" fitting, vacuum pump and vacuum gauge to disconnected EVAP 2-way valve hose. (Scheme 32) Apply vacuum slowly and continuously while observing gauge. If vacuum stabilizes momentarily at 0.2-0.6 in. Hg, go to next step. If vacuum does not stabilize momentarily at less than 0.2 in. Hg or more than 0.6 in. Hg, replace EVAP 2-way valve and retest.
2. Move vacuum hose from vacuum fitting to pressure fitting on pump. Switch "T" fitting vacuum hose to pressure hose on gauge. Slowly pressurize vapor line while monitoring pressure gauge. If pressure stabilizes momentarily at more than 0.3 in. Hg, EVAP 2-way valve is okay. If pressure does not stabilize at more than 0.3 in. Hg, replace EVAP 2-way valve and retest.

Scheme 32

VTEC ROCKER ARM TEST

Note. Special tools required: VTEC Air Adapter (07VAJ-P8A010A) VTEC Air Stopper (070AJ-0030100) Air Pressure Regulator (07AAJ-PNAA100)

1. Start engine and let run for 5 minutes, then turn ignition off.
2. Remove intake manifold. See INTAKE MANIFOLD «REMOVAL & INSTALLATION»(ref-98284-S05190566582001052100000) in ENGINES article.
3. Remove valve covers.
4. Set No. 1 piston on TDC.
5. Push on the intake mid rocker arm (A) for No. 1 cylinder. See (a) in (Scheme 33). The mid rocker arm should move independently of the primary rocker arm (B) and secondary rocker arm (C). If intake mid rocker arm (A) does not move independently remove rocker arms as an assembly, then check that the pistons in mid rocker arm (A) and primary rocker arm (B) move smoothly. If any rocker arm needs replacing, replace primary, mid and secondary rocker arms as an assembly and retest. If mid rocker arm moves freely, go to next step.
6. Repeat step 5 on the remaining mid rocker arms with each piston on TDC. When all are checked and pass, go to next step.
7. Ensure shop air compressor indicates over 100 psi (690 kPa). Go to next step.
8. Inspect valve clearances.
9. Remove No. 1 and No. 5 intake rocker shaft mounting bolts. Install and connect the special tools as shown. See (b) in (Scheme 33).
10. Loosen the valve on regulator and apply specified air pressure: 64-78 psi (440-540 kPa). NOTE: If the synchronizing pistons do not move after applying air pressure, move primary and secondary rocker arm up and down manually.
11. Ensure the intake primary rocker arm (A) and intake secondary rocker arm (B) are mechanically connected to piston and mid rocker arm (C) does not move when pushed manually. See (c) in (Scheme 33). If any intake mid rocker arm (C) move independently of the primary rocker arm (A) and secondary rocker arm (B), replace rocker arms as a set.
12. Remove tools. Tighten rocker shaft bolts to 17 ft. lbs. (24 N.m). Reinstall valve covers and intake manifold.

Scheme 33

See also:
• MDX, 3.2CL & 3.2TL
• EMISSION SYSTEMS & SUB-SYSTEMS
• DIAGNOSTIC TROUBLE CODE DEFINITIONS
• TROUBLESHOOTING MALFUNCTION INDICATOR LIGHT
• RETRIEVING DIAGNOSTIC TROUBLE CODES
• CKP PATTERN LEARN PROCEDURE
• PCM IDLE LEARN PROCEDURE
• TEST EQUIPMENT
• CONNECTOR IDENTIFICATION
• P0097
• P0098
• P0107
• P0108
• P0112
• P0113
• P0116
• P0117
• P0118
• P0122
• P0123
• P0125
• P0128
• P0133
• P0134
• P0135
• P0137
• P0138
• P0139
• P0141
• P0171
• P0201
• P0222
• P0223
• P0300
• P0301
• P0325
• P0335
• P0339
• P0340
• P0344
• P0401
• P0403
• P0404
• P0406
• P0420
• P0443
• P0451
• P0452
• P0453
• P0455
• P0456
• P0457
• P0461
• P0462
• P0463
• P0496
• P0497
• P0498
• P0499
• P0506
• P0507
• P0563
• P0603
• P0606
• P0627
• P0641
• P0657
• P0685
• P1077
• P1078
• P1128
• P1129
• P1297
• P1298
• P1450
• P1451
• P1454
• P1460
• P1683
• P1684
• P2101
• P2108
• P2118
• P2122
• P2123
• P2127
• P2128
• P2135
• P2138
• P2176
• P2195
• P2199
• P2227
• P2228
• P2237
• P2238
• P2243
• P2245
• P2251
• P2252
• P2279
• P2413
• P2422
• P2552
• P2610
• P2627
• P2628
• P2646
• P2647
• P2648
• P2649
• P2A00
• U0107
• PCM RESET PROCEDURE/CLEARING DIAGNOSTIC TROUBLE CODES
• PCM REMOVAL & REPLACEMENT
• DTC/PCM "A" HARNESS CONNECTOR TERMINAL IDENTIFICATION
• VTEC ROCKER ARM TEST
• VALVE TEST