Engine Controls - Tests W/codes: Diagnosis Lexus LS II

MALFUNCTION INDICATOR LIGHT (MIL) INSPECTION

Note. The CHECK engine light located on instrument cluster is known as Malfunction Indicator Light (MIL). Inspect MIL to ensure it is operational and will come on if a Diagnostic Trouble Code (DTC) is set.

1. Turn ignition on with engine off. MIL should come on and remain on. If MIL does not come on, check bulb circuit on instrument cluster and wiring circuit between MIL and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. See «ECM LOCATION»(ref-22204-S22700583272001010300000) .
2. Start engine and ensure MIL goes off. If MIL remains on with engine running, a malfunction is detected. Proceed to «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-22204-S40932683902001010300000) .

TESTING PROCEDURE

To ensure correct diagnosis and repair, testing should be done in the following sequence

1. Record Customer Complaint - Ensure all customer complaints or observations are recorded. Test drive vehicle with customer when necessary for malfunction verification.
2. Retrieve Diagnostic Trouble Codes - Connect appropriate OBD-II scan tool. Retrieve codes and record any freeze-frame data. See «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-22204-S40932683902001010300000) .
3. Clear Trouble Codes - Clear codes using scan tool. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-22204-S17369188322001010300000) .
4. Perform Visual Inspection - Inspect all connectors of suspect circuit or component. Ensure all connections are clean and tight.
5. Confirm Symptoms & Trouble Codes - Perform road test. Determine if original symptoms are still present. Retrieve codes.
6. Diagnose & Repair Diagnostic Trouble Codes - Perform diagnosis and repair procedures as needed. See appropriate tests in this article. If no codes are present, proceed to the «TESTS W/O CODES»(ref-22205) article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.).
7. Verification Procedure - After repairs have been completed, clear all diagnostic trouble codes. Refer to «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-22204-S17369188322001010300000) . Perform road test. Ensure no codes are present and all symptoms and/or complaints have been repaired.

RETRIEVING DIAGNOSTIC TROUBLE CODES

Note. Diagnostic Trouble Codes (DTCs) may be retrieved using Lexus scan tool or On-Board Diagnostic (OBD-II) scan tool that complies with SAE standard J-1978. Lexus scan tool or OBD-II scan tool may be operated in NORMAL mode when retrieving trouble codes. Only Lexus scan tool may be used in CHECK mode when retrieving DTCs.

NORMAL mode is used to retrieve DTCs from Engine Control Module (ECM). CHECK mode is used to check for DTCs when operating vehicle to simulate conditions in which DTC was set. CHECK mode contains a higher sensing ability to detect malfunctions. CHECK mode helps determine malfunctions caused by poor electrical connections, which are difficult to determine using NORMAL mode.

Note. If using Lexus scan tool, when ignition is turned from ON to ACC or OFF position or scan tool is switched from NORMAL mode to CHECK mode, all DTCs and freeze-frame data will be erased. DO NOT switch modes until all DTCs and freeze-frame data are recorded.

CHECK Mode Code Retrieval (Lexus Scan Tool Only)

1. Ensure vehicle battery is fully charged. Apply parking brake. Shift transmission/transaxle into Neutral (M/T) or Park (A/T). Turn A/C and all accessories off. Ensure throttle is in idle position.
2. Turn ignition off. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 DLC No. 3 connector is located under left side of instrument panel. Turn ignition on with engine off. Turn scan tool on.
3. Switch scan tool from NORMAL mode to CHECK mode. CHECK mode is operational if MIL on instrument cluster flashes. Start engine. Ensure MIL goes off. Try to simulate conditions of driveability complaint described by customer. NOTE: If ignition is turned from ON to ACC or OFF position, all DTCs and freeze-frame data will be erased. DO NOT switch modes until all DTCs and freeze-frame data are recorded.
4. Record any DTCs and freeze-frame data displayed for system diagnosis. If driveability problem exists and no codes are present, go to «TESTS W/O CODES»(ref-22205) article for diagnosis by symptom.
5. If any DTCs are present, perform appropriate circuit test. See DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION table. For more information on freeze-frame data, see FREEZE-FRAME DATA under INTRODUCTION. For information on 2-trip detection logic codes, see TWO-TRIP DETECTION LOGIC under INTRODUCTION.
6. After repairs for DTC have been completed, DTC must be cleared from ECM memory. See CLEARING DIAGNOSTIC TROUBLE CODES.

CLEARING DIAGNOSTIC TROUBLE CODES

1. After performing repairs, clear ECM memory of all stored Diagnostic Trouble Codes (DTCs) and freeze-frame data. DTCs and freeze-frame data may be cleared by using scan tool and scan tool manufacturer's instructions. NOTE: If using Lexus Scan Tool, DTCs and freeze-frame data may be cleared by switching from CHECK mode to NORMAL mode or from NORMAL mode to CHECK mode.
2. DTCs and freeze-frame data may also be cleared by removing EFI fuse from junction block located in engine compartment. DTCs and freeze-frame data may also be cleared by disconnecting negative battery cable. However, other memory functions (clock, radio, alarm, seats, etc.) will be cancelled and must be reset.

DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION

TROUBLE CODE TEST DRIVE CONFIRMATION

1. On certain Diagnostic Trouble Codes (DTCs), once DTC has been cleared from ECM memory, a DTC test drive confirmation test can be performed to verify repairs made and that DTC does not reset. The test drive confirmation test will duplicate the conditions required to set specified DTCs.
2. Test drive confirmation test lists the procedure to be performed to check that DTC does not reset. Test drive confirmation tests apply only to specific DTCs. Test drive confirmation test will be included with proper DTC circuit test in appropriate test(s) in this article.

DLC NO. 3 INSPECTION

1. If scan tool displays UNABLE TO CONNECT TO VEHICLE when scan tool is connected, try scan tool on another vehicle. If scan tool operates on another vehicle, go to next step. If scan tool does not operate on another vehicle, problem is probably with scan tool.
2. Check DLC No. 3 for loose or damaged terminals. Ensure DLC No. 3 terminals are in correct position in connector. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If connector and terminals are okay, go to next step.
3. Check voltage and resistance between ground and the specified terminal on DLC No. 3. (Scheme 1) Also, refer to the «DLC NO. 3 VOLTAGE & RESISTANCE SPECIFICATIONS»(ref-22204-S16547333222001010300000) table. If voltage and resistance readings are not as specified, check wiring circuit. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article.

Note. Terminal No. 2 (No. 7 on ES300) on DLC No. 3 provides the pulse generation during the information transmission from the Engine Control Module (ECM).

DLC NO. 3 VOLTAGE & RESISTANCE SPECIFICATIONS

Scheme 1

Diagnosis & Repair

1. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Start engine and allow it to idle. Using scan tool, monitor MAF flow rate. If scan tool reading is 0.0 gm/sec., go to next step. If reading is 271.0 gm/sec. or more once engine is at normal operating temperature, go to step 5).
2. Disconnect MAF sensor harness connector. Ensure ignition is on. Using DVOM, measure voltage between ground and terminal No. 1 (White wire) at MAF sensor connector. If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, locate and repair open in White wire between MAF sensor connector and ECM.
3. Access ECM behind glove box. Start engine. Backprobing ECM connector, check voltage between ground and terminal No. 8 (Blue/Yellow wire) at ECM E13 connector. (Scheme 2) If voltage is 1.1-1.5 volts, replace ECM and retest.
4. If voltage is not 1.1-1.5 volts, locate and repair open or short circuit in Blue/Yellow wire between MAF sensor and ECM. If Blue/Yellow wire is okay, replace MAF sensor and retest.
5. Access ECM behind glove box. Turn ignition off. Backprobing ECM connector, check for continuity between ground and terminal No. 21 (Green/White wire) at ECM E13 connector. If continuity does not exist, replace ECM and retest. If continuity exists, locate and repair open in Green/White wire between MAF sensor and ECM. If Green/White wire is okay, replace MAF sensor.

Scheme 2

If only DTC P0101 is displayed, replace MAF sensor and retest. If other codes are displayed, diagnose and repair those codes first and retest.

1. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on. Using scan tool on, monitor IAT sensor temper ature. If temperature displayed is same as actual intake air temperature, check component and ECM connections. Problem is intermittent.
2. If temperature displayed is 284°F (140°C) or more, go to step 5). If temperature displayed is -40°F (-40°C), turn ignition off. Disconnect MAF sensor harness connector. Connect a jumper wire between terminals No. 3 (Yellow/Black wire) and No. 4 (Brown wire) at MAF sensor harness connector. Turn ignition on. Monitor IAT sensor temperature on scan tool.
3. If temperature displayed is 284°F (140°C) or more, replace MAF sensor and retest. If temperature displayed is less than 284°F (140°C), turn ignition off. Remove jumper wire. Access ECM behind glove box. Connect jumper wire between terminals No. 18 (Yellow/Black wire) and No. 22 (Brown wire) at ECM E13 connector (Scheme 2)
4. If temperature displayed on scan tool is 284°F (140°C) or more, check and repair wiring harness between MAF harness connector and ECM. If temperature displayed on scan tool is not 284°F (140°C) or more, replace ECM and retest.
5. Turn ignition off. Disconnect MAF sensor harness connector. Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace MAF sensor and retest. If temperature displayed is not -40°F (-40°C), turn ignition off and go to next step.
6. Access ECM behind glove box. Disconnect ECM E13 harness connector. Turn ignition on. If temperature displayed is -40°F (-40°C), repair short circuit in wiring harness between MAF sensor and ECM. If temperature displayed by scan tool is not -40°F (-40°C), replace ECM and retest.

1. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on. Using scan tool, monitor ECT sensor temperatu re. If temperature displayed is same as engine coolant temperature, check component and ECM connections. Problem is intermittent.
2. If temperature displayed is 284°F (140°C), go to step 5). If temperature displayed is -40°F (-40°C), turn ignition off. Disconnect ECT sensor harness connector. Connect a jumper wire between terminals No. 2 (Red/Blue wire) and No. 1 (Brown wire) at ECT sensor harness connector. Turn ignition on. Using scan tool, monitor ECT sensor temperature.
3. If temperature displayed is 284°F (140°C) or more, replace ECT sensor and retest. If temperature displayed is less than 284°F (140°C), turn ignition off. Remove jumper wire. Access ECM behind glove box. Connect jumper wire between terminals No. 20 (Red/Blue wire) and No. 22 (Brown wire) at ECM E13 connector. (Scheme 2)
4. If temperature displayed on scan tool is 284°F (140°C) or more, check and repair wiring harness between ECT harness connector and ECM. If temperature displayed on scan tool is not 284°F (140°C) or more, replace ECM and retest.
5. Turn ignition off. Disconnect ECT sensor harness connector. Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace ECT sensor and retest. If temperature displayed is not -40°F (-40°C), turn ignition off.
6. Access ECM behind glove box. Disconnect ECM E13 connector. Turn ignition on. If temperature displayed is -40°F (-40°C), repair short circuit in wiring harness between ECT sensor and ECM. If temperature displayed by scan tool is not -40°F (-40°C), replace ECM and retest.

If only DTC P0116 is displayed, replace ECT sensor and retest. If other codes are displayed, diagnose and repair those codes first and retest.

1. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on. Using scan tool, monitor throttle valve openi ng percentage. Opening percentage should be approximately 10 with fully closed throttle. Depress accelerator pedal to floor (WOT). Opening percentage should be approximately 70. If percentages are within specification, check all connections. Problem may be intermittent. If percentages are not within specification, go to next step.
2. Disconnect TP sensor harness connector. Turn ignition on. Using DVOM, measure voltage between ground and Blue/Red wire at TP sensor harness connector. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, go to step 5).
3. Turn ignition off. Using ohmmeter, measure resistance between terminals No. 1 (Brown wire) and No. 4 (Blue/Red wire) at TP sensor component connector. Resistance should be 3100-7200 ohms. Also, measure resistance between terminals No. 1 (Brown wire) and No. 3 (Yellow wire). Resistance should be 340-6300 ohms with throttle fully closed, and 2400-11,200 ohms with throttle fully open. If any reading is not within specification, replace TP sensor. If all readings are within specification, go to next step.
4. Connect TP sensor harness connector. Access ECM harness connectors behind glove box. Turn ignition on. Backprobing ECM harness connector, measure voltage between terminals No. 7 (Yellow wire) and No. 22 (Brown wire) at ECM E13 connector. (Scheme 2) Voltage should be.3-.8 volt with throttle fully closed, and 3.2-4.9 volts with throttle fully open (WOT). If voltages are as specified, replace ECM and retest. If voltages are not as specified, check for open or short circuit in Yellow wire or Brown wire between ECM and TP sensor. Repair as necessary.
5. Access ECM harness connectors behind glove box. Turn ignition on. Backprobing ECM harness connector, measure voltage between terminals No. 1 (Blue/Red wire) and No. 22 (Brown wire) at ECM E13 connector. If voltage is 4.5-5.5 volts, locate and repair open in Blue/Red wire between TP sensor and ECM. If voltage is not 4.5-5.5 volts, replace ECM and retest.

If only DTC P0121 is displayed, replace TP sensor and retest. If other codes are displayed, diagnose and repair those codes first and retest.

1. Connect scan tool to Data Link Connector (DLC) No. 3 connector. see scheme 1 Start engine and warm to normal operating temperature. Using scan tool, monitor bank No. 1, sensor No. 1 and bank No. 2, sensor No. 1. Snap accelerate engine 3 times. Sensors should indicate a rich signal (.45 volt or more) at least once.
2. If a rich signal is indicated for both sensors, replace ECM and retest. If either sensor does not display a rich signal, check for open or short circuit in wiring harness between ECM and suspect sensor. Repair as necessary. If wiring harness is okay, replace oxygen sensor and retest.

Test Drive Confirmation

1. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 If using Lexus scan tool, switch to CHECK mode. Start and warm engine to normal operating temperature. Drive vehicle at 31-40 MPH for 1-3 minutes. Stop vehicle and allow to idle for one minute. If malfunction exists, MIL will illuminate.
2. If using OBD-II scan tool, start and warm engine to normal operating temperature. Drive vehicle at 31-40 MPH for 1-3 minutes. Stop vehicle and allow to idle for one minute. Turn vehicle off. Repeat driving and idle part of test. If malfunction exists, MIL will illuminate.

1. Check or open or short circuit in wiring harness between ECM and oxygen sensor. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring harness is okay, connect scan tool. see scheme 1
2. Start engine and warm to normal operating temperature. Monitor heated oxygen sensor output voltage and short-term fuel trim. If scan tool indicates a lean condition (.55 volt or less, +20 trim) or rich condition (.4 volt or more, -20 trim), see DTC P0171: SYSTEM TOO LEAN (FUEL TRIM), DTC P0172: SYSTEM TOO RICH (FUEL TRIM) circuit test.
3. If scan tool indicates other than in step 2), operate engine at 2500 RPM for 90 seconds. Monitor oxygen sensor voltage. If voltage constantly fluctuates from less than 0.4 volt to more than 5.5 volts, perform TEST DRIVE CONFIRMATION. If voltage does not fluctuate as specified, replace sensor and retest.

Diagnosis & Repair Procedure

If only DTC P0133 or P0153 is displayed, replace oxygen sensor and retest. If other codes are displayed, diagnose and repair those codes first and retest.

1. Access ECM harness connectors behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector. If DTC P0135 is set, measure voltage between ground and terminal No. 15 (Red wire) at ECM E13 connector. If DTC P0141 is set, measure voltage between ground and terminal No. 4 (Red wire) at ECM E11 connector. If DTC P0155 is set, measure voltage between ground and terminal No. 14 (Yellow wire) at ECM E13 connector. If DTC P0161 is set, measure voltage between ground and terminal No. 1 (Blue wire) at ECM E11 connector.
2. If voltage is 9-14 volts, replace ECM and retest. If voltage is not 9-14 volts, turn ignition off. Disconnect appropriate oxygen sensor harness connector. Using ohmmeter, measure resistance between terminals No. 1 and 2 at oxygen sensor connector. See the «IDENTIFYING OXYGEN SENSOR HEATER TERMINALS»(ref-22204-S30411591552001010300000) table. IDENTIFYING OXYGEN SENSOR HEATER TERMINALS Application Terminal No. 1 Terminal No. 2 Bank 1, Sensor 1 Red Wire White Wire Bank 1, Sensor 2 Red Wire White Wire Bank 2, Sensor 1 Yellow Wire White Wire Bank 2, Sensor 2 Blue Wire White Wire
3. With sensor temperature at 68°F (20°C), resistance should be 11-16 ohms. If resistance is as specified, check and repair wiring harness between EFI main relay, oxygen sensor and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If resistance is not as specified, replace sensor and retest.

1. If any other codes are displayed other than DTC P0136 or P0156, diagnose and repair those codes first. If only DTC P0136 or P0156 is displayed, check for open or short circuit in wiring harness between ECM and sensor. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair wiring as necessary.
2. If wiring harness is okay, connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Start and warm engine to normal operating temperature. Monitor oxygen sensor output voltage. Raise engine speed to 2500 RPM for 3 minutes. Voltage should fluctuate from.4 volt or less to.5 volt or more.
3. If voltage responds correctly, check wiring harness connection. Problem may be intermittent. If voltage does not respond correctly, replace oxygen sensor and retest.

See DTC P0130 & P0150 - HEATED OXYGEN SENSOR FAULT circuit test.

See DTC P0133 & P0153: HEATED OXYGEN SENSOR circuit test.

See DTC P0135, P0141, P0155 & P0161: HEATED OXYGEN SENSOR CIRCUIT.

See DTC P0136 & P0156: HEATED OXYGEN SENSOR CIRCUIT.

See DTC P0135, P0141, P0155 & P0161: HEATED OXYGEN SENSOR CIRCUIT.

1. Check all air induction components. Repair as necessary. If air induction components are okay, connect scan tool. see scheme 1 Start engine and warm to normal operating temperature. Monitor heated oxygen sensor output voltage and short-term fuel trim.
2. If scan tool indicates a lean condition (.55 volt or less, +20 trim) or rich condition (.4 volt or more, -20 trim), go to next step. If results are other than specified, see DTC P0130 & P0150 - HEATED OXYGEN SENSOR FAULT circuit test.
3. Check fuel pressure. See BASIC DIAGNOSTIC PROCEDURES article. Repair as necessary. If fuel pressure is okay, check fuel injectors. See «SYSTEM/COMPONENT TESTS»(ref-22208) article. Replace injectors as necessary.
4. If all injectors are okay, check Mass Airflow (MAF) sensor and Engine Coolant Temperature (ECT) sensor. See «SYSTEM/COMPONENT TESTS»(ref-22208) article. Replace as necessary. If both components are okay, check ignition system. See IGNITION CHECKS in BASIC DIAGNOSTIC PROCEDURES article. Repair as necessary. If ignition system is okay, replace ECM and retest.

Circuit Description

A misfire is determined by the ECM. The ECM uses signals provided by the crankshaft and camshaft position sensors. If the engine speed rate has changed enough to equal a preset number, a misfire is detected and the MIL is illuminated. If the misfire rate is high enough, and driving conditions will cause catalytic converter damage or overheating, the MIL blinks when a misfire is occurring.

DTC is set when misfiring of random cylinders is detected during any particular 200 or 1000 revolutions. Possible causes are

1. Ignition system.
2. Injector(s).
3. Fuel pressure.
4. EGR system.
5. Engine compression.
6. Valve clearance.
7. Valve timing.
8. Mass Airflow (MAF) sensor.
9. Engine Coolant Temperature (ECT) sensor.

1. Check spark plugs and ignition system. See BASIC DIAGNOSTIC PROCEDURES article. Repair as necessary. If ignition system is okay, ensure ignition is off.
2. Access ECM harness connectors behind glove box. Turn ignition on. Using DVOM, backprobe ECM connector and measure voltage between ground and injector terminals at ECM E14 connector. See «IDENTIFYING INJECTOR TERMINALS»(ref-22204-S18177377002001010300000) table. If voltage is 9-14 volts for each circuit, go to step 4). If voltage is not 9-14 volts, go to next step. IDENTIFYING INJECTOR TERMINALS Injector No. (1) Terminal No. Wire Color 1 10 Yellow 2 9 Black 3 8 Blue 4 7 Red 5 6 Green 6 5 Red/Blue 7 16 White 8 15 Black/White (1) Terminals are located in ECM E14 connector.
3. Disconnect injector of misfiring cylinder. Using ohmmeter, measure resistance between injector terminals. With injector temperature at 68°F (20°C), if resistance is 13.4-14.2 ohms, check for open or short circuit between ECM and injector. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If resistance is not 13.4-14.2 ohms, replace injector.
4. Check fuel pressure. See BASIC DIAGNOSTIC PROCEDURES article. Repair as necessary. If fuel pressure is okay, check fuel injector performance. See «SYSTEM/COMPONENT TESTS»(ref-22208) article. Replace as necessary.
5. If all injectors are okay, check EGR system. See «SYSTEM/COMPONENT TESTS»(ref-22208) article. Repair as necessary. If EGR system is okay, check MAF sensor and ECT sensor. See «SYSTEM/COMPONENT TESTS»(ref-22208) article. Replace as necessary. If both components are okay, check engine compression, valve clearance and valve timing. See BASIC DIAGNOSTIC PROCEDURES article. Repair as necessary.

See DTC P0300: RANDOM MISFIRE DETECTED.

See DTC P0300: RANDOM MISFIRE DETECTED .

1. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Disconnect ED1 connector. ED1 connector is a wire-to-wire conne ctor located near rear of air intake. Connector is a Black 3-pin connector.
2. Connect a jumper wire between Black wire of male connector to Green wire of female connector. Connect another jumper wire between Green wire of male connector to Black wire of female connector. Turn ignition on. Clear trouble codes. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-22204-S17369188322001010300000). Start and warm engine to normal operating temperature.
3. Snap accelerate engine 3 times. Retrieve codes. See «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-22204-S40932683902001010300000) article. If same code is repeated as before, go to next step. If code has changed, go to step 5).
4. Check circuit(s) between ED1 connector and ECM harness connector for open or short circuit. Repair as necessary. If circuits are okay, replace ECM and retest. Ensure ED1 male connector terminals are returned to their original position.
5. Check circuit(s) between ED1 connector and knock sensor for open or short circuit. If DTC P0325 has changed to DTC P0330, check knock sensor circuit on right bank side. If DTC P0330 changed to DTC P0325, check knock sensor circuit on left bank. Repair as necessary. If harness is okay, replace knock sensor. Ensure ED1 male connector terminals are returned to their original position.

1. Disconnect CKP sensor harness connector. Remove sensor if necessary. Using ohmmeter, measure resistance between CKP sensor terminals. If resistance is as specified, go to next step. Refer to the «CKP SENSOR RESISTANCE SPECIFICATIONS»(ref-22204-S19739400022001010300000) table. If resistance is not as specified, replace sensor and retest. CKP SENSOR RESISTANCE SPECIFICATIONS Temperature °F (°C) Ohms 14-50 (-10-50) 835-1400 122-212 (50-100) 1060-1645
2. Check for open or short circuit in wiring harness between CKP sensor and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring is okay, go to next step.
3. Check CKP sensor for proper installation. Also, check for damaged signal plate teeth. Tighten sensor or replace signal plate as necessary. If sensor installation and signal plate teeth are okay, replace ECM and retest.

1. Remove "V" bank cover. Remove battery clamp cover. Remove air cleaner air inlet hose. Disconnect No. 1 and No. 2 CMP sensor connectors. Using ohmmeter, measure resistance between No. 1 CMP sensor and No. 2 CMP sensor connector terminals. If resistance is as specified, go to next step. See «CMP SENSOR RESISTANCE SPECIFICATIONS»(ref-22204-S07766246062001010300000) table. If resistance is not as specified, replace sensor(s) and retest. CMP SENSOR RESISTANCE SPECIFICATIONS Temperature °F (°C) Ohms 14-50 (-10-50) 835-1400 122-212 (50-100) 1060-1645
2. Check for open or short circuit in wiring harness between each sensor and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring is okay, go to next step.
3. Check sensors for proper installation. Tighten sensor as necessary. If sensor installation is okay, replace ECM and retest.

1. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Start and warm engine to normal operating temperature. Operate vehicle at 43-56 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes. Turn igni-tion off.
2. Start engine and allow to idle. Operate vehicle at 43-56 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes.
3. Check READINESS TESTS mode on scan tool. If COMPL is displayed on scan tool and MIL is not illuminated, system is normal. If INCPL is displayed and MIL is not illuminated, repeat test drive procedure.

Diagnosis & Repair (Using Lexus Scan Tool)

1. Connect Lexus scan tool to DLC No. 3. Turn ignition on. Using scan tool, read EGR gas temperature. Temperature should be 50°F (10°C). If temperature is as specified, go to step 5). If temperature is not as specified, go to next step. If temperature displayed is 37.6°F (3.1°C), locate and repair open circuit in EGR temperature sensor circuit.
2. Disconnect EGR temperature sensor harness connector. Connect jumper wire between harness connector terminals. EGR gas temperature displayed should be 318.7°F (159.3°C). If temperature displayed is not as specified, go to next step. If temperature displayed is as specified, check sensor connectors and terminals. Repair as necessary. If connectors are okay, replace sensor and retest.
3. Remove jumper wire. Turn ignition off. Access ECM behind glove box. Connect jumper wire between ECM harness connector terminals No. 2 (Red/Yellow wire) at ECM E12 connector and No. 22 (Brown wire) at ECM E13 connector. (Scheme 2) Turn ignition on. EGR gas temperature displayed should be 318.7°F (159.3°C).
4. If temperature displayed is as specified, locate and repair open in wiring harness between ECM and EGR temperature sensor. If temperature displayed is not as specified, replace ECM and retest.
5. Check EGR valve. See «SYSTEM/COMPONENT TESTS»(ref-22208) article. Replace EGR valve as necessary. If EGR valve is okay, replace ECM and retest.

Diagnosis & Repair (Using OBD-II Scan Tool)

1. Remove EGR temperature sensor. Place sensor and a thermometer into a container of water. Heat container and check sensor resistance. If resistance is as specified, go to next step. See the EGR TEMPERATURE SENSOR RESISTANCE SPECIFICATIONSs table below. If resistance is not as specified, replace sensor. EGR TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS Temperature °F (°C) Ohms 122 (50) 64,000-97,000 212 (100) 11,000-16,000 302 (150) 2000-4000
2. Check for open or short circuit in wiring harness between EGR temperature sensor and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring is okay, go to next step.
3. Check EGR valve. See «SYSTEM/COMPONENT TESTS»(ref-22208) article. Replace EGR valve as necessary. If EGR valve is okay, replace ECM and retest.

1. Connect Lexus scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on. Read EGR gas temperature. Temperature should be 302°F (150°C) or less (not immediately after driving). If temperature is as specified, go to step 4). If temperature is not as specified, go to next step. NOTE: If EGR gas temperature displayed is 318.7°F (159.3°C), a short circuit exists in EGR gas temperature sensor circuit.
2. Disconnect EGR temperature sensor. EGR gas temperature displayed should be 37.6°F (3.1°C). If temperature displayed is not as specified, go to next step. If temperature displayed is as specified, check sensor connectors and terminals. Repair as necessary. If connectors are okay, replace sensor and retest.
3. Turn ignition off. Access ECM behind glove box. Disconnect ECM E12 connector. (Scheme 2) Turn ignition on. EGR gas temperature displayed should be 37.6°F (3.1°C). If temperature displayed is not as specified, replace ECM and retest. If temperature displayed is as specified, repair wiring harness between ECM E12 connector and EGR temperature sensor connector.
4. Check EGR valve. See «SYSTEM/COMPONENT TESTS»(ref-22208) article. Replace EGR valve as necessary. If EGR valve is okay, replace ECM and retest.

1. Remove EGR temperature sensor. Place sensor and a thermometer into a container of water. Heat container and check sensor resistance. If resistance is as specified, go to next step. See EGR TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS table below. If resistance is not as specified, replace sensor. EGR TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS Temperature °F (°C) Ohms 122 (50) 64,000-97,000 212 (100) 11,000-16,000 302 (150) 2000-4000
2. Check for open or short circuit in wiring harness between EGR temperature sensor and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring harness is okay, go to next step.
3. Check EGR valve. See «SYSTEM/COMPONENT TESTS»(ref-22208) article. Replace EGR valve as necessary. If EGR valve is okay, replace ECM and retest.

1. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe connector and measure voltage between ground and terminals No. 27 (Red/Blue wire), No. 28 (Red/Yellow wire), No. 29 (Red/White wire) and No. 30 (Red/Black wire) at ECM E14 connector. (Scheme 2) If all readings are 9-14 volts, go to step 3). If any reading is not 9-14 volts, go to next step.
2. Disconnect EGR valve connector. Turn ignition on. Measure voltage between ground and terminals B1 (White wire) and B2 (White wire) at EGR valve harness connector. If both readings are 9-14 volts, go to next step. If any reading is not 9-14 volts, check for open or short circuit in wiring harness between battery and EGR valve. Repair as necessary.
3. Measure resistance between terminal B1 and terminals S1 and S3 at EGR valve. Also, measure resistance between terminal B2 and terminals S2 and S4. (Scheme 1) If each reading is 20-23 ohms, go to next step. If any reading is not 20-23 ohms, replace EGR valve.
4. Check for open or short circuit in wiring harness between EGR valve and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring harness is okay, replace ECM and retest.

Scheme 3

1. If any other codes are displayed other than DTC P0420 or P0430, diagnose and repair those codes first. If only DTC P0420 or P0430 is displayed, go to next step.
2. Check heated oxygen sensor circuits. DTC P0130 & P0150 - HEATED OXYGEN SENSOR FAULT circuit test. Replace oxygen sensor(s) as necessary. If oxygen sensors are okay, replace catalytic converter and retest.

1. Check with vehicle driver if fuel tank cap was loose when refueling. If fuel tank cap was loose prior to refueling, it probably was cause of DTC to set. If fuel tank cap was not loose, check for cracks, deformations or loose connections in the following: Fuel tank. Charcoal canister. Fuel tank filler pipe. Hose and tubes around fuel tank and charcoal canister. Repair as necessary. If components are okay, go to next step.
2. Check if fuel tank cap is an original manufacturer's cap. If fuel tank cap is an original manufacturer's cap, go to next step. If fuel tank cap is not an original manufacturer cap, replace cap with a manufacturer's cap.
3. Check if fuel cap is installed properly. Reinstall cap as necessary. If fuel cap is installed properly, go to next step.
4. Check for damaged fuel tank cap and gasket. Replace fuel cap as necessary. If fuel tank cap and gasket are okay, go to next step.
5. Remove fuel tank cap. Visually inspect fuel tank filler neck for damage. Replace filler neck as necessary. If filler neck is okay, go to next step.
6. Check vacuum hoses between vapor pressure sensor and VSV for vapor pressure sensor, and between vapor pressure sensor and charcoal canister. Check hoses for correct installation, looseness and damage. Repair as necessary. If vacuum hoses are okay, go to next step.
7. Check hose and tube between fuel tank and charcoal canister for correct installation and damage. Repair as necessary. If hose and tube are okay, go to next step.
8. Visually inspect charcoal canister for cracks or damage. Replace canister as necessary. If canister is okay, go to next step.
9. Access ECM harness connectors behind glove box. Turn ignition on. Backprobing ECM harness connector, measure voltage between terminals No. 1 (Blue/Red wire) and No. 22 (Brown wire) at ECM E13 connector. (Scheme 2) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM and retest.
10. Backprobing ECM harness connector, measure voltage between terminals No. 18 (Pink/Green wire) at ECM E11 connector and No. 22 (Brown wire) at ECM E13 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on top of charcoal canister and is located in left front of engine compartment. Connect a vacuum pump to sensor. If voltage is 3.0-3.7 volts without vacuum applied and.5 volt or less with 1.2-19.7 in. Hg (8-135 kPa) applied, go to step 12). If voltage is not as specified, go to next step.
11. Check for an open or short in wiring harness between vapor pressure sensor and ECM. See the appropriate wiring diagram in the «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring is okay, replace vapor pressure sensor.
12. Disconnect vacuum hose from charcoal canister. Ensure fuel tank cap is installed properly. Using compressed air, apply.71 psi (.05 kg/cm 2 ) to fuel tank. If tank does not hold pressure for a minimum of one minute, replace fuel tank. If tank holds pressure, no fault is indicated at this time. Probable cause of DTC to set was an incorrectly installed fuel tank cap.

1. Check EVAP VSV, vapor pressure sensor VSV and vapor pressure sensor wiring harness connectors for damaged pins, corrosion and loose wires. Repair as necessary. If connectors are okay, go to next step. For component locations, see appropriate illustration in the «THEORY/OPERATION»(ref-22207) article.
2. Check all EVAP related vacuum hoses for cracks, looseness and correct routing. Repair as necessary. If vacuum hoses are okay, go to next step. For proper vacuum hose routing, see «VACUUM DIAGRAMS»(ref-22209) article.
3. Access ECM harness connectors behind glove box. Turn ignition on. Backprobing ECM harness connector, measure voltage between terminals No. 1 (Blue/Red wire) and No. 22 (Brown wire) at ECM E13 connector. (Scheme 2) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM and retest.
4. Backprobing ECM harness connector, measure voltage between terminals No. 18 (Pink/Green wire) at ECM E11 connector and No. 22 (Brown wire) at ECM E13 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on top of charcoal canister and is located in left front of engine compartment. Connect a vacuum pump to sensor. If voltage is 3.0-3.7 volts without vacuum applied and.5 volt or less with 1.2-19.7 in. Hg (8-135 kPa) applied, go to step 6). If voltage is not as specified, go to next step.
5. Check for an open or short in wiring harness between vapor pressure sensor and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring is okay, replace vapor pressure sensor.
6. Connect Lexus scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on. Using scan tool, select ACTIVE TEST mode. Disconnect EVAP VSV vacuum hose from charcoal canister. Start engine. Connect a vacuum gauge to disconnected vacuum hose. When EVAP VSV is activated by scan tool, vacuum should be present. When EVAP VSV is not activated, no vacuum should be present. If vacuum is as specified, go to step 9). If vacuum is not as specified, go to next step.
7. Check EVAP VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in «SYSTEM/COMPONENT TESTS»(ref-22208) article. Replace VSV as necessary. If VSV is okay, go to next step.
8. Check for an open or short in wiring harness between EFI main relay, EVAP VSV and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring is okay, replace ECM and retest.
9. Connect Lexus scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Turn ignition on. Disconnect vapor pressure sensor VSV. Start and run engine. Select ACTIVE TEST mode on scan tool. Backprobing ECM harness connector, measure voltage between terminals No. 18 (Pink/Green wire) at ECM E11 connector and No. 22 (Brown wire) at ECM E13 connector. (Scheme 2) With EVAP VSV activated, voltage should be 2 volts or less. If voltage is as specified, go to step 11). If voltage is not as specified, go to next step.
10. Check vapor pressure sensor VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in «SYSTEM/COMPONENT TESTS»(ref-22208) article. Replace VSV as necessary. If VSV is okay, go to next step.
11. Check for an open or short in wiring harness between EFI main relay, vapor pressure sensor VSV and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring is okay, go to next step.
12. Remove fuel tank cap. Disconnect vapor pressure sensor VSV. Select ACTIVE TEST mode on scan tool. Start engine. Using scan tool, switch EVAP VSV on. Backprobing ECM harness connector, measure voltage between terminals No. 18 (Pink/Green wire) at ECM E11 connector and No. 22 (Brown wire) at ECM E13 connector 5 seconds after switching EVAP VSV from on to off. If voltage is 2.5 volts or less, replace ECM and retest. If voltage is more than 2.5 volts, replace charcoal canister.

Scheme 4

1. Check EVAP VSV, vapor pressure sensor VSV and vapor pressure sensor wiring harness connectors for damaged pins, corrosion and loose wires. Repair as necessary. If connectors are okay, go to next step. For component locations, see appropriate illustration in the «THEORY/OPERATION»(ref-22207) article.
2. Check all EVAP related vacuum hoses for cracks, looseness and correct routing. Repair as necessary. If vacuum hoses are okay, go to next step. For proper vacuum hose routing, see «VACUUM DIAGRAMS»(ref-22209) article.
3. Access ECM harness connectors behind glove box. Turn ignition on. Backprobing ECM harness connector, measure voltage between terminals No. 1 (Blue/Red wire) and No. 22 (Brown wire) at ECM E13 connector. (Scheme 2) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM and retest.
4. Backprobing ECM harness connector, measure voltage between terminals No. 18 (Pink/Green wire) at ECM E11 connector and No. 22 (Brown wire) at ECM E13 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on top of charcoal canister and is located in left front of engine compartment. Connect a vacuum pump to sensor. If voltage is 3.0-3.7 volts without vacuum applied and.5 volt or less with 1.2-19.7 in. Hg (8-135 kPa) applied, go to step 6). If voltage is not as specified, go to next step.
5. Check for an open or short in wiring harness between vapor pressure sensor and ECM. Refer to the appropriate wiring diagram in the «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring is okay, replace vapor pressure sensor.
6. Disconnect EVAP VSV vacuum hoses. For VSV location, see the «VACUUM DIAGRAMS»(ref-22209) article. Apply air pressure to VSV port "E". (Scheme 4) Air should not flow from port "F". Access ECM harness connectors behind glove box. Turn ignition on. Connect jumper wire between ground and terminal No. 8 (Blue/Black wire) at ECM E12 connector. (Scheme 2) Air should flow from port "F". If VSV functions as specified, g o to step 9). If VSV does not function as specified, go to next step.
7. Check EVAP VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in the «SYSTEM/COMPONENT TESTS»(ref-22208) article. Replace VSV as necessary. If VSV is okay, go to next step.
8. Check for an open or short in wiring harness between EFI main relay, EVAP VSV and ECM. Refer to appropriate wiring diagram in the «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring is okay, replace ECM and retest.
9. Disconnect vapor pressure sensor VSV vacuum hoses. VSV is mounted on top of EVAP charcoal canister. Apply air pressure to VSV port "E". (Scheme 5) Air should flow from port "G". Access ECM harness connectors behind glove box. Turn ignition on. Connect jumper wire between ground and terminal No. 17 (Violet/Green wire) at ECM E11 connector. (Scheme 2) Air should flow from port "F". If VSV does not function as specified, go to next step. If VSV functions as specified, check charcoal canister. Refer to EMISSION SYSTEMS & SUB-SYSTEMS in the «SYSTEM/COMPONENT TESTS»(ref-22208) article. Replace canister as necessary.
10. Check vapor pressure sensor VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in «SYSTEM/COMPONENT TESTS»(ref-22208) article. Replace VSV as necessary. If VSV is okay, go to next step.
11. Check for an open or short in wiring harness between EFI main relay, vapor pressure sensor VSV and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring is okay, replace ECM and retest.

Scheme 5

1. Access ECM harness connectors behind glove box. Turn ignition on. Backprobing ECM harness connector, measure voltage between terminals No. 1 (Blue/Red wire) and No. 22 (Brown wire) at ECM E13 connector. (Scheme 2) If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM and retest.
2. Backprobing ECM harness connector, measure voltage between terminals No. 18 (Pink/Green wire) at ECM E11 connector and No. 22 (Brown wire) at ECM E13 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on top of charcoal canister and is located in left front of engine compartment. Connect a vacuum pump to sensor. If voltage is 3.0-3.7 volts without vacuum applied and.5 volt or less with 1.2-19.7 in. Hg (8-135 kPa) applied, replace ECM and retest. If voltage is not as specified, go to next step.
3. Check for an open or short in wiring harness between vapor pressure sensor and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring is okay, replace vapor pressure sensor.

1. Connect scan tool to Data Link Connector (DLC) No. 3. see scheme 1 Start engine. Turn scan tool on. Road test vehicle and using sc an tool, read vehicle speed value. If vehicle speed matches scan tool speed value, replace ECM and retest. If vehicle speed does not match scan tool speed value, go to next step.
2. Check speedometer operation. If speedometer is operating properly, go to next step. If speedometer is not operating properly, check for open or short in VSS circuit. See «SYSTEM/COMPONENT TESTS»(ref-22208) article. Repair as necessary.
3. Access ECM behind glove box. Turn ignition off. Disconnect ECM E13 connector. (Scheme 2) Measure resistance between terminals No. 4 (Red wire) and No. 9 (Green wire) at ECM E13 connector. If resistance is 560-680, replace ECM and retest. If resistance is not 560-680 ohms, go to next step.
4. Remove VSS from transmission. Measure resistance between VSS terminals. If resistance is 560-680, go to next step. If resistance is not 560-680 ohms, replace VSS and retest.
5. Connect DVOM between VSS terminals. Set DVOM to lowest DC volt scale. While passing a magnet back and forth over tip of VSS, observe DVOM. Voltage should pulse (voltage is extremely low). If VSS operates as specified, check for open or short circuit in wiring harness between VSS and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If VSS does not operate as specified, replace VSS and retest.

1. Disconnect IAC valve connector. Measure resistance between terminal B1 and terminals S1 and S3. Also, measure resistance between terminal B2 and terminals S2 and S4 at IAC valve harness connector. (Scheme 1) If each reading is 31-61 ohms (cold) or 38-71 ohms (hot), go to next step. If any reading is not 31-61 ohms (cold) or 38-71 ohms (hot), replace IAC valve.
2. Remove IAC valve. Connect a jumper wire between positive battery terminal and terminals B1 and B2 at IAC valve. Using another jumper wire, connect one end of jumper to negative battery terminal. Touch remaining end of jumper to IAC valve terminals S1, S2, S3 and S4 in that order. IAC valve should move to closed position.
3. Ensure jumper is still connected between positive battery terminal and terminals B1 and B2. Using another jumper wire, connect one end of jumper to negative battery terminal. Touch remaining end of jumper to IAC valve terminals S4, S3, S2 and S1 in that order. IAC valve should move to open position.
4. If IAC valve does not operate as specified, replace IAC valve. If IAC valve operates as specified, check for open or short circuit in wiring harness between main relay, IAC valve and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring harness is okay, no problem is indicated at this time. Diagnose by symptom. See «TESTS W/O CODES»(ref-22205) article.

1. Connect Lexus scan tool to Data Link Connector (DLC) No. 3 connector. see scheme 1 Disconnect TP sensor connector. Connect a jumper wire between Brown and Green wires at TP sensor harness connector. Turn ignition on. Using scan tool, read CTP switch signal. If CTP switch signal is off, remove jumper wire and go to next step. If CTP switch signal is on, check TP sensor connector. Repair as necessary and retest. If connector is okay, replace TP sensor.
2. Access ECM behind glove box. Turn ignition off. Connect a jumper wire between terminals No. 32 (Green wire) at ECM E14 connector and No. 22 (Brown wire) at ECM E13 connector. (Scheme 2) Turn ignition on. Using scan tool, read CTP switch signal. If CTP switch signal is off, replace ECM and retest. If CTP switch signal is on, locate and repair open circuit in wiring harness between ECM and TP sensor.

1. Disconnect TP sensor connector. Turn ignition on. Using DVOM, measure voltage between Green wire and Brown wire at TP sensor harness connector. If voltage is not 9-14 volts, check for open circuit in Green and Brown wires between ECM and TP sensor. Repair as necessary.
2. If wiring is okay, replace ECM. If voltage is 9-14 volts, check TP sensor connector. Repair as necessary. If connector is okay, replace TP sensor and retest.

If only DTC P1100 is displayed, replace ECM and retest. If other codes are displayed, diagnose and repair those codes first and retest.

1. Access ECM behind glove box. Start engine and raise engine speed to 2000 RPM or more. Backprobing ECM connector, measure voltage between ground and terminal No. 1 (Green/Red wire) at ECM E12 connector. (Scheme 2)
2. Voltage should be 9-14 volts within 60 seconds of starting engine, and 0-3 volts 60 seconds or more after starting engine. If voltage is not as specified, go to next step. If voltage is as specified, replace ECM and retest.
3. Remove fuel pump relay from engine compartment relay box. Check for continuity between terminals No. 1 and 2 at fuel pump relay. (Scheme 6) If continuity exists, go to next step. If continuity does not exist, replace relay.
4. Apply battery voltage to terminals No. 1 and 2. (Scheme 6) Again, check for continuity between terminals No. 3 and 4 at fuel pump relay. If continuity exists, replace relay. If continuity does not exist, check for open or short circuit in wiring harness between relay and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary.

Scheme 6

1. Access appropriate distributor. Disconnect coil wire from distributor. Using insulated pliers, hold end of coil wire 1/2" from ground. Crank engine for 1-2 seconds. If spark is present, go to next step. If spark is not present, go to step 4).
2. Check for open or short circuit in IGF and IGT signal circuits between ignitor and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If circuits are okay, go to next step.
3. Disconnect ignitor connector. For component location, see appropriate illustration in the «THEORY/OPERATION»(ref-22207) article. Access ECM behind glove box. Backprobing ECM connector, measure voltage between ground and terminals No. 12 (Yellow/Green wire) and No. 26 (Yellow/Black wire) at ECM E14 connector. (Scheme 2) If any reading is not 4.5-5.5 volts, replace ECM and retest. If both readings are 4.5-5.5 volts, replace ignitor. If DTC P1300 is set, replace ignitor with 5-wire connector. If DTC P1305 is set, replace ignitor with 4-wire connector.
4. Check for open or short circuit in IGT signal circuit between ignitor and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If circuit is okay, go to next step.
5. Backprobing ECM connector, measure voltage between ground and terminals No. 24 (Yellow wire) and No. 25 (Black/Red wire) at ECM E14 connector while cranking engine. (Scheme 2) If each reading is.1-4.5 volts, go to next step. If any reading is not.1-4.5 volts, replace ECM and retest.
6. Disconnect ignitor connector. Backprobing ECM connector, measure voltage between ground and terminals No. 24 (Yellow wire) and No. 25 (Black/Red wire) at ECM E14 connector while cranking engine. If each reading is.1-4.5 volts, go to next step. If any reading is not.1-4.5 volts, replace ECM and retest.
7. Measure voltage between ground and terminal No. 3 (Black/Red wire) at both ignitors. With ignition switch in ON or START positions, voltage should be 9-14 volts. If voltage is as specified, go to next step. If voltage is not as specified, check and repair ignitor power source circuit. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article.
8. Check for an open or short in wiring harness between ignition switch, ignition coil and ignitor. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring is okay, go to next step.
9. Disconnect ignition coil connectors. Remove No. 2 ignition coil located at top center of engine. Measure resistance of both coils. See «IGNITION COIL RESISTANCE SPECIFICATIONS (OHMS)»(ref-22204-S10792046652001010300000) table. If resistance is as specified, replace ignitor. If DTC P1300 is set, replace ignitor with 5-wire connector. If DTC P1305 is set, replace ignitor with 4-wire connector. If resistance is not as specified, replace coil.

IGNITION COIL RESISTANCE SPECIFICATIONS (OHMS)

See DTC P0335 OR P1335: CRANKSHAFT POSITION (CKP) SENSOR CIRCUIT test.

1. Access ECM harness connectors behind glove box. Turn ignition on. Remove intake air duct. Disconnect sub-throttle actuator connector. (Scheme 7) Backprobing ECM harness connector, measure voltage between ground and terminal No. 12 (Yellow/Green wire) at ECM E13 connector. (Scheme 2)
2. Voltage should be.3-.8 volt (throttle closed) and 3.2-4.9 volts (throttle open). Measure voltage between ground and terminal No. 31 (Red/Black wire) at ECM E14 connector. Voltage should be 0-3 volts (throttle closed) and 9-14 volts (throttle open). If voltage is not as specified, go to next step. If voltage is as specified, no problem is detected at this time. Problem is intermittent.
3. Disconnect SUB-TP sensor connector. (Scheme 7) Measure resistance between terminals No. 1 (Brown wire) and No. 3 (Yellow/Green wire) at SUB-TP sensor. Resistance should be 340-6300 ohms (throttle closed) and 2400-11,200 ohms (throttle open).
4. Measure resistance between terminals No. 1 (Brown wire) and No. 2 (Red/Black wire) at SUB-TP sensor. Resistance should be less than 500 ohms (throttle closed) and infinite (throttle open). If resistances are as specified, go to next step. If resistances are not as specified, adjust SUB-TP sensor. See «ADJUSTMENTS»(ref-22210) article. If adjustment is okay, replace sensor.
5. Check for open or short in wiring harness between SUB-TP sensor and ECM. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article. Repair as necessary. If wiring is okay, replace ECM and retest.

Scheme 7

If only DTC P1401 is displayed, replace SUB-TP sensor and retest. If other codes are displayed, diagnose and repair those codes first and retest.

1. Check stoplights. If stoplights do not function properly, repair as necessary and retest system. If stoplights function properly, go to next step.
2. Access ECM behind glove box. Locate ECM E11 connector. (Scheme 2) Turn ignition on. Backprobing ECM connector, measure voltage between ground and terminal No. 16 (Green/Red wire) at ECM E11 connector. With brake pedal depressed, voltage should be 7.5-14.0 volts. With brake pedal released, voltage should be less than 1.5 volt. If voltage is not as specified, go to next step. If voltage is as specified, check wire harness and connectors. Problem is intermittent.
3. Check for short in wiring harness between ECM and stoplight switch. Repair as necessary and retest system. If wiring harness is okay, replace ECM. Retest system.

1. Access ECM behind glove box. Backprobing ECM connector, measure voltage between ground and terminal No. 14 (Black/Yellow wire) at ECM E11 connector. (Scheme 2) If voltage is not 9-14 volts, go to next step. If voltage is 9-14 volts, replace ECM and retest.
2. Remove and inspect EFI fuse (20-amp) from junction block on left side of engine compartment. If fuse is blown, check cause of blown fuse and repair as necessary. If fuse is okay, check and repair wiring harness or connector between battery, EFI fuse and ECM.

Knock sensors are located on either side of cylinder block. Sensor generates voltage when engine block vibrates due to knocking. DTC is set if there is a ECM malfunction for knock control. Possible cause is

1. ECM.

If only DTC P1605 is displayed, replace ECM and retest. If other codes are displayed, diagnose and repair those codes first and retest.

Park/neutral position switch is on whenever shift lever is in "N" or "P" position. With switch on, ECM terminal NSW is grounded via starter relay (zero voltage at terminal NSW). With shift lever in "D", "3", "2", "L" or "R" position, switch is off (battery voltage at terminal NSW). DTC is set under the following conditions

1. Two or more switches are on simultaneously for "N", "2" or "L" position.
2. If park/neutral position switch is on while driving vehicle for 30 seconds or more at 44 MPH or more.
3. If park/neutral position switch is on while driving vehicle for 30 seconds or more with engine speed at 1500-2500 RPM.

1. Check park/neutral position switch. See ENGINE SENSORS & SWITCHES in «SYSTEM/COMPONENT TESTS»(ref-22208) article. Replace switch as necessary. If switch is okay, go to next step.
2. Access ECM behind glove box. Turn ignition on. Measure voltage between ground and terminal No. 14 (Blue/Yellow wire) at ECM E14 connector. (Scheme 2) With shift lever in "P" or "N" position, voltage should be zero volts. With shift lever in any other position, voltage should be 9-14 volts. If voltage is as specified, go to next step. If voltage is not as specified, check for open or short circuit is wiring harness between ECM and park/neutral position switch. See appropriate wiring diagram in «WIRING DIAGRAMS»(ref-22206) article.
3. Measure voltage between ground and terminal No. 13 (Green wire) at ECM E12 connector. With shift lever in "2" position, voltage should be 9-14 volts. With shift lever in any other position, voltage should be zero volts. If voltage is as specified, go to next step. If voltage is not as specified, check for open or short circuit in wiring harness between ECM and park/neutral position switch.
4. Measure voltage between ground and terminal No. 12 (Green/Black wire) at ECM E12 connector. With shift lever in "L" position, voltage should be 9-14 volts. With shift lever in any other position, voltage should be zero volts. If voltage is as specified, replace ECM and retest. If voltage is not as specified, check for open or short circuit in wiring harness between ECM and park/neutral position switch.