Engine Controls - Self-Diagnostics - 2.3L: Other Mazda 6 GG

Pending DTCs

Pending codes appear when a problem is detected in a monitored system. The Malfunction Indicator Light (MIL) is illuminated when a problem is detected in 2 consecutive drive cycles. The pending code is stored in Powertrain Control Module (PCM) during the first drive cycle when a failed system is detected. If a system does not fail during the second drive cycle, PCM concludes that system has returned to normal or problem was mistakenly detected, and deletes pending code. If system failure is detected during a second drive mode, PCM concludes that suspect system has failed, deletes pending code, and illuminates MIL and stores Diagnostic Trouble Codes (DTC).

Intermittent Failures

Intermittent failures may cause Malfunction Indicator Light (MIL) to flicker or illuminate and go out after the intermittent fault goes away. However, the corresponding trouble code will be retained in PCM memory. If related fault does not reoccur within a certain time frame, related trouble code will be erased from PCM memory. Intermittent failures may be caused by a sensor, connector or wiring related problems. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.

FREEZE FRAME DATA

Freeze frame data is technical data which indicates engine's condition at time of first malfunction. This data will remain in memory even if another emission-related DTC is stored, with the exception of misfire or fuel system DTCs. Once freeze frame data for misfire or fuel system DTC is stored, it will overwrite any previous data after which freeze frame data will not be overwritten again.

PCM CONFIGURATION

Note. If PCM is replaced with a new one, PCM stores DTC P0602 and illuminates MIL even though no malfunction is detected. After completing "PCM Configuration" procedure, clear DTC P0602 using WDS or equivalent. MIL goes off after three drive cycles with no failure. (DTCs remain in PCM.)

1. Connect WDS or equivalant to DLC-2.
2. Set up WDS or equivalent (including vehicle recognition.
3. Select MODULE PROGRAMMING.
4. Select PROGRAMMABLE MODULE INSTALLATION.
5. Select PCM and perform procedures according to directions on WDS or equivalent screen.
6. Retrieve DTCs with WDS or equivalent, then verify there are no DTCs present. If DTC is present, perform applicable DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000) .

OBD-II DRIVE MODES

Performing Drive Mode inspects OBD-II system for proper operation and must be performed to ensure that no additional DTCs are present. During Drive Mode the following systems are monitored

1. EGR system
2. Oxygen sensor and oxygen sensor heater
3. Three Way Catalytic (TWC) converter
4. Fuel, misfire and Evaporative Emission (EVAP) system

Note. Vehicle speed and engine speed detected by the PCM may differ from that indicated by the speedometer and tachometer. Use the WDS or equivalent to monitor vehicle speed. If the OBD II system inspection is not completed during the Drive Mode, the following causes are considered: The OBD II system detects the malfunction. The Drive Mode procedure is not completed correctly. Disconnecting the battery will reset the memory. Do not disconnect the battery during and after Drive Mode. The WDS or equivalent can be used at anytime through the course of Drive Mode to monitor the completion status. Monitoring can be done by viewing the ON BOARD SYSTEM READINESS menu.

Note. The PCM adaptive memory status can be confirmed with RFCFLAG PID. If RFCFLAG PID is ON, MODE 1 - PCM ADAPTIVE MEMORY PRODUCE DRIVE MODE is not necessary, because PCM already has adaptive memory. If RFCFLAG PID is OFF, MODE 1 - PCM ADAPTIVE MEMORY PRODUCE DRIVE MODE should be performed before MODE 2 - EGR SYSTEM REPAIR VERIFICATION DRIVE MODE or MODE 3 - HO2S HEATER, HO2S & TWC REPAIR VERIFICATION DRIVE MODE .

Mode 1 - PCM Adaptive Memory Produce Drive Mode

1. Start engine and warm up completely.
2. Verify following conditions and correct if necessary. All accessory loads (A/C, headlights, blower fan, rear window defroster) are off. Initial ignition timing and idle speed are within specification.
3. Perform no load test, racing engine at 2500-3500 RPM for more than 15 seconds.
4. Continuously perform no load test, racing engine at 4500-5000 RPM for more than 15 seconds.
5. Idle engine for more than 60 seconds after cooling fan has stopped.
6. Turn ignition off then on again.
7. Access RFCFLAG PID to confirm PCM adaptive memory status. If RFCFLAG PID is "Learned", «PCM ADAPTIVE MEMORY PRODUCE DRIVE MODE»(ref-151885-S34300930692003010900000) is completed. If RFCFLAG PID is still "Not Learned", go back to step 1 .

Mode 2 - EGR System Repair Verification Drive Mode

1. Access to RFCFLAG PID to confirm PCM adaptive memory status. If RFCFLAG PID is "Not Learned", perform "PCM Adaptive Memory Produce Drive Mode" first. If RFCFLAG PID is ON, start engine and warm up completely.
2. Verify all accessory loads (A/C, headlights, blower fan, rear window defroster) are off.
3. Drive vehicle as shown in graph. (Scheme 14)
4. Stop vehicle and access ON BOARD SYSTEM READINESS to inspect DRIVE MODE COMPLETION STATUS. If completed, Readiness Function Check (RFC) flag changes from NO to YES. If not completed, turn ignition off and repeat testing from step 3.
5. Access DIAGNOSTIC MONITORING TEST RESULTS menu of GENERIC OBD-II FUNCTIONS to inspect monitor results. If MEAS are within specification, repair is completed. If MEAS are not within specification, repair is not completed.
6. Verify no DTCs are available.

Scheme 14

Mode 3 - HO2S Heater, HO2S & TWC Repair Verification Drive Mode

1. Access to RFCFLAG PID to confirm PCM adaptive memory status. If RFCFLAG PID is "Not Learned", perform «MODE 1 - PCM ADAPTIVE MEMORY PRODUCE DRIVE MODE»(ref-151885-S34300930692003010900000) first. If RFCFLAG PID is ON, start engine and warm up completely.
2. Verify all accessory loads (A/C, headlights, blower fan, rear window defroster) are off.
3. Start engine and let idle it for more than 5 minutes.
4. Drive vehicle under one of following conditions: Vehicle speed is more than 55 MPH for one minute (MTX: 5th gear/ATX: D range). Vehicle speed is more than 50 MPH for one minute (MTX: 4th gear/ATX: D range).
5. Continue to drive vehicle while maintaining speed between 45-55 MPH for 3 minutes (MTX: 5th gear ATX: D range).
6. Stop vehicle and access ON BOARD SYSTEM READINESS to inspect Drive Mode completion status. If completed, RFC flag changes from NO to YES. If not completed, turn ignition off. Go back to step 3 .
7. Access DIAGNOSTIC MONITORING TEST RESULTS to inspect monitor results. If MEAS are within specification, repair is completed. If MEAS are not within specification, repair is not completed.
8. Verify no DTCs are available.

Mode 4 - EVAP System Repair Verification Drive Mode

Note. If MODE 4 - EVAP SYSTEM REPAIR VERIFICATION DRIVE MODE cannot be performed (you cannot drive vehicle under MODE 4 - EVAP SYSTEM REPAIR VERIFICATION DRIVE MODE condition), perform Evaporative System Test procedure as an alternative. See FUEL EVAPORATIVE SYSTEM - EXCEPT PROTEGE & PROTEGE5 under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. MODE 4 - EVAP SYSTEM REPAIR VERIFICATION DRIVE MODE can be performed regardless RFCFLAG condition.

1. Verify all following PIDs are within the following specifications. All PIDs must be within specifications before engine is started to initiate the evaporative system test: BARO: 21.3 in. Hg (72.3 kPa) or higher IAT: 41-95°F (5-35°C) FTL: 15-85 percent VPWR: 10.9-14.6 volts
2. Clear DTC from PCM memory using WDS or equivalent.
3. Start engine and idle it for more than 10 seconds, then turn ignition key to OFF. Leave vehicle for 5 hours or more.
4. Start engine and idle for more than 15 minutes.
5. Drive vehicle at 40-50 MPH for more than 5 minutes.
6. Stop vehicle and turn ignition off.
7. Leave vehicle as is for 10 minutes or more.
8. Start engine.
9. Access to ON BOARD SYSTEM READINESS to inspect DRIVE MODE COMPLETION STATUS: If completed, RFC flag changes from NO to YES. If not completed, turn ignition off. Go back to step 1 .
10. Access DIAGNOSTIC MONITORING TEST RESULTS to inspect monitor results. If MEAS are not within specification, repair has not been completed.
11. Verify no DTCs are available.

SUMMARY

If no diagnostic trouble code is present but driveability problem still exists, proceed to TROUBLE SHOOTING - NO CODES article for symptom diagnosis or intermittent diagnostic procedures.

Detection Condition

Actual valve timing is over-advanced by 25 degrees from target valve timing when Oil Control Valve (OCV) is controlled in maximum valve timing retard condition.

Possible Cause

Possible causes are

1. Loose timing belt or improper valve timing due to timing belt slippage
2. OCV malfunction
3. PCM malfunction
4. Spool valve in OCV is stuck in advance position
5. Variable valve timing actuator is stuck in advance position

Actual valve timing is over-retarded by 5 degrees. From target valve timing for 5 seconds when the Oil Control Valve (OCV) system control is within feed-back range. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Loose timing belt or improper valve timing due to timing belt slippage.
2. OCV malfunction Low engine oil pressure Spool valve in OCV is stuck in retard position.
3. PCM malfunction.
4. Variable Valve Timing (VVT) actuator is stuck in retard position. Following oil runners are clogged or have leakage: Oil runners, between oil pressure switch and OCV Between OCV and VVT actuator In VVT actuator

PCM monitors front HO2S heater control signal at PCM 30-pin harness connector terminal "4A" (White/Black wire). If PCM turns front HO2S heater off but front HO2S heater circuit has low voltage, PCM determines that front HO2S heater circuit has malfunction. Front HO2S heater is controlled by duty signal. This is a Continuous Monitor (O2 sensor heater). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for the same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Front HO2S malfunction
2. Open circuit between front HO2S and PCM
3. Open circuit between ignition switch and front HO2S
4. PCM malfunction
5. Poor connection at front HO2S or PCM connector
6. Short to ground circuit between front HO2S and PCM

Scheme 15

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect Front HO2S Connector For Poor Connection - Turn ignition off. Disconnect front HO2S 4-pin harness connector. Inspect for poor connection (such as damaged, pulled-out pins, corrosion). If any malfunctions are present, repair or replace terminal. After repair, go to step 9. If malfunctions are not found, go to next step.
4. Inspect Front HO2S Heater - Inspect front HO2S heater. See «HEATED OXYGEN SENSOR»(ref-151892-S27992571522003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If front HO2S heater is okay, go to next step. If front HO2S heater is not okay, replace front HO2S. After repair, go to step 9.
5. Inspect Power Circuit Of Front HO2S Heater For Open Circuit - Turn ignition on, engine off. Measure voltage in White/Red wire between front HO2S 4-pin harness connector terminal "C" and body ground. (Scheme 15) If battery voltage is present, go to next step. If battery voltage is not present, repair or replace harness for open circuit in White/Red wire between main relay (inside engine fuse/relay box) and HO2S 4-pin harness connector terminal "C". See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 9.
6. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM connectors. Inspect for poor connection (such as damaged, pulled-out pins, corrosion). If no malfunctions are present, go to next step. If any malfunctions are present, repair terminal. After repair, go to step 9.
7. Inspect Control Circuit Of Front HO2S Heater For Short To Ground - Check for continuity between front HO2S 4-pin harness connector terminal "D" and body ground. If continuity is not present, go to next step. If continuity is present, repair or replace wire harness for short circuit to ground. After repair, go to step 9.
8. Inspect Control Circuit Of Front HO2S Heater For Open Circuit - Check for continuity in White/Black wire between front HO2S 4-pin harness connector terminal "D" and PCM 30-pin harness connector terminal "4A". If continuity is present, go to next step. If continuity is not present, repair or replace wire harness for open circuit in White/Black wire between front HO2S 4-pin harness connector terminal "D" and PCM 30-pin harness connector terminal "4A". See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to next step.
9. Verify Trouble Shooting Of DTC P0031 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm it up completely. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
10. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors front HO2S heater control signal at PCM 30-pin harness connector terminal "4A" (White/Black wire). If PCM turns front HO2S heater on but front HO2S heater circuit has high voltage, PCM determines that front HO2S heater circuit has malfunction. Front HO2S heater is controlled by a duty signal. This is a Continuous Monitor (O2 sensor heater). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Front HO2S heater malfunction
2. Front HO2S or PCM terminal is shorted
3. PCM malfunction
4. Short to power circuit between front HO2S and PCM

PCM monitors rear HO2S heater control signal at PCM 30-pin harness connector terminal "4D" (White/Green wire). If PCM turns rear HO2S heater off but rear HO2S heater circuit has low voltage, PCM determines that rear HO2S heater circuit has malfunction. This is a Continuous Monitor (HO2S heater). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Open circuit between ignition switch and rear HO2S
2. Open circuit between rear HO2S and PCM
3. PCM malfunction
4. Poor connection at rear HO2S or PCM connector
5. Rear HO2S malfunction
6. Short to ground circuit between rear HO2S and PCM

Scheme 16

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect Rear HO2S Connector For Poor Connection - Turn ignition off. Disconnect rear HO2S 4-pin harness connector. Inspect for poor connection (such as damaged, pulled-out pins, corrosion). If malfunction is not found, go to next step. If any malfunction is present, repair or replace terminal. After repair, go to step 9.
4. Inspect Rear HO2S Heater - Inspect rear HO2S heater. Refer to «HEATED OXYGEN SENSOR»(ref-151892-S27992571522003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If rear HO2S heater is okay, go to next step. If rear HO2S heater is faulty, replace the rear HO2S. After repair, go to step 9.
5. Inspect Rear HO2S Heater Power Circuit For Open Circuit - Turn ignition on, engine off. Measure voltage between rear HO2S 4-pin harness connector terminal "C" (White/Red wire) and body ground. (Scheme 16) If battery voltage is present, go to next step. If battery voltage is not present, repair or replace harness for open circuit in White/Red wire between main relay (inside engine fuse/relay box) and HO2S 4-pin harness connector terminal "C". See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 9.
6. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 30-pin harness connector. Inspect for poor connection (such as damaged, pulled-out pins, corrosion). If malfunctions are not found, go to next step. If any malfunctions are found, repair terminal. After repair, go to step 9.
7. Inspect Rear HO2S Heater Control Circuit For Short To Ground - Check for continuity in White/Green wire between rear HO2S 4-pin harness connector terminal "D" and body ground. If continuity is present, repair or replace harness for short circuit to ground in White/Green wire between rear HO2S 4-pin harness connector terminal "D" and PCM 30-pin harness connector terminal "4D". After repair, go to step 9.
8. Inspect Rear HO2S Heater Control Circuit For Open Circuit - Check for continuity White/Green wire between rear HO2S 4-pin harness connector terminal "D" and PCM 30-pin harness connector terminal "4D". (Scheme 16) If continuity is present, go to next step. If continuity is not present, repair or replace harness for open circuit in White/Green wire between rear HO2S 4-pin harness connector terminal "D" and PCM 30-pin harness connector terminal "4D". See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to next step.
9. Verify Trouble Shooting Of DTC P0037 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm it up completely. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
10. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors rear HO2S heater control signal at PCM 30-pin harness connector terminal "4D" (White/Green wire). If PCM turns rear HO2S heater on but rear HO2S heater circuit has high voltage, PCM determines that rear HO2S heater circuit has malfunction. This is a continuous monitor (O2 sensor heater). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. PCM malfunction
2. Rear HO2S heater malfunction
3. Rear HO2S or PCM terminal is shorted
4. Short to power circuit between rear HO2S and PCM

PCM compares actual input signal from Mass Airflow/Intake Air Temperature (MAF/IAT) sensor with expected input signal from MAF/IAT sensor which PCM calculates by input voltage from Throttle Position (TP) sensor or engine speed.

1. If mass intake airflow amount is less than 0.66 lb/min. (5.0 grams/sec.) for 5 seconds and throttle opening angle is more than 50 percent with engine running, PCM determines that detected mass intake air flow amount is too low.
2. If mass intake air flow amount is more than 12.7 lb/min. (96 grams/sec.) for 5 seconds and engine speed is less than 2000 RPM with engine running, PCM determines that detected mass intake airflow amount is too high.

This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Electrical corrosion in MAF RETURN circuit
2. Electrical corrosion in MAF signal circuit
3. MAF/IAT sensor malfunction
4. TP sensor malfunction
5. Voltage drops in ground circuit
6. Voltage drops in MAF signal circuit

PCM monitors input voltage from Mass Airflow/Intake Air Temperature (MAF/IAT) sensor when engine is running. If input voltage at PCM 30-pin harness connector terminal "1P" (Gray/Black wire) is less than 0.21 volt, PCM determines MAF/IAT circuit has a malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Connector or terminal malfunction
2. MAF/IAT sensor malfunction
3. Open circuit in Gray/Black wire between MAF/IAT sensor 5-pin harness connector terminal "C" and PCM 30-pin harness connector terminal "1P"
4. Open circuit in White wire between main relay and MAF/IAT sensor 5-pin harness connector terminal "A"
5. Short circuit to ground in Gray/Black wire between MAF/IAT sensor 5-pin harness connector terminal "C" and PCM 30-pin harness connector terminal "1P"

Scheme 17

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect MAF/IAT Sensor Connector For Poor Connection - Turn ignition off. Disconnect MAF/IAT sensor 5-pin harness connector. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunction is not present, go to next step. If any malfunction is present, repair or replace suspected terminal or MAF/IAT sensor. After repair, go to step 8.
4. Inspect Power Supply Circuit For Open Circuit - Turn ignition on, engine off. Inspect voltage at MAF/IAT sensor 5-pin harness connector terminal "A" (White wire). (Scheme 17) If battery voltage is present, go to next step. If battery voltage is not present, check for open circuit in White wire between MAF/IAT sensor 5-pin harness connector terminal "A" and main relay (inside engine fuse/relay box). See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Repair or replace harness. After repair, go to step 8.
5. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM 30-pin harness connector. Inspect for poor connection (such as damaged, pulled-out pins, corrosion). If malfunction is not present, go to next step. If any malfunction is present, repair terminal. After repair, go to step 8.
6. Inspect MAF/IAT Sensor Signal Circuit For Open Circuit - Check for continuity in Gray/Black wire between MAF/IAT sensor 5-pin harness connector terminal "C" and PCM 30-pin harness connector terminal "1P". If continuity is present, go to next step. If continuity is not present, repair open circuit in Gray/Black wire between MAF/IAT sensor 5-pin harness connector terminal "C" and PCM 30-pin harness connector terminal "1P". After repair, go to step 8.
7. Inspect MAF/IAT Sensor Signal Circuit For Shorts - Check continuity between following circuits: MAF/IAT sensor 5-pin harness connector terminal "C" (Gray/Black wire) and body ground. MAF/IAT sensor 5-pin harness connector terminal "C" (Gray/Black wire) and terminal "B" (Gray wire). If continuity is present, repair short circuit in suspected wire or replace harness. After repair, go to next step. If continuity is not present, replace MAF/IAT sensor. After repair, go to next step.
8. Verify Trouble Shooting Of DTC P0102 Completed - Make sure to reconnect all disconnected connectors. Turn ignition on, engine off. Clear DTC from PCM memory using WDS or equivalent. Start engine and warm up completely. If same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
9. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors input voltage from Mass Airflow/Intake Air Temperature (MAF/IAT) sensor when engine is running. If input voltage at PCM 30-pin harness connector terminal "1P" (Gray/Black wire) is more than 4.9 volts, PCM determines that MAF/IAT circuit has a malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Connector or terminal malfunction
2. MAF/IAT sensor malfunction
3. Open circuit in MAF/IAT sensor ground circuit (Brown wire)
4. Short circuit to power in Gray/Black wire between MAF/IAT sensor 5-pin harness connector terminal "C" and PCM 30-pin harness connector terminal "1P"

PCM monitors differences between intake manifold vacuum and atmospheric pressure at idle. If difference is less than 1.9 in. Hg (6.4 kPa), PCM determines that there is a Manifold Absolute Pressure (MAP) sensor performance problem. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible cause is, MAP sensor malfunction or substandard performance.

PCM monitors input voltage from Manifold Absolute Pressure (MAP) sensor when intake air temperature is more than 50°F (10°C). If input voltage at PCM 30-pin harness connector terminal "1J" (Yellow/Black wire) is less than 0.10 volt, PCM determines that MAP sensor circuit has a malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Connector or terminal malfunction
2. MAP sensor malfunction
3. MAP sensor signal circuit and MAP sensor ground circuit are shorted to each other
4. Open circuit in Red/Black wire between MAP sensor 4-pin harness connector terminal "C" and PCM 30-pin harness connector terminal "2K"
5. PCM malfunction
6. Short circuit to ground in Yellow/Black wire between MAP sensor 4-pin harness connector terminal "D" and PCM 30-pin harness connector terminal "1J"

PCM monitors input voltage from Manifold Absolute Pressure (MAP) sensor when intake air temperature is more than 50°F (10°C). If input voltage at PCM 30-pin harness connector terminal "1J" (Yellow/Black wire) is more than 4.92 volts, PCM determines MAP sensor circuit has a malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible Causes

Possible causes are

1. Connector or terminal malfunction
2. MAP sensor malfunction
3. MAP sensor signal circuit shorts to constant voltage supply circuit
4. Open circuit in Brown wire between MAP sensor 4-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "2H"
5. Open circuit in Yellow/Black wire between MAP sensor 4-pin harness connector terminal "D" and PCM 30-pin harness connector terminal "1J"
6. PCM malfunction

DTC is set when intake air temperature is more than engine coolant temperature by 104°F (40°C) and ignition is on. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. MAF/IAT sensor malfunction
2. PCM malfunction
3. Poor connection at MAF/IAT sensor or PCM connectors

The PCM monitors Mass Airflow/Intake Air Temperature (MAF/IAT) sensor signal at PCM 30-pin harness terminal "2E" (Blue/Black wire). If PCM detected MAF/IAT sensor voltage less than 0.16 volt, PCM determines MAF/IAT signal circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. MAF/IAT sensor malfunction
2. Short to ground circuit in Blue/Black wire between MAF/IAT sensor 5-pin harness connector terminal "D" and PCM 30-pin harness connector terminal "2E"
3. Short in harness between IAT signal circuit and IAT ground circuit
4. PCM malfunction

The PCM monitors Mass Airflow/Intake Air Temperature (MAF/IAT) sensor signal at PCM 30-pin harness connector terminal "2E" (Blue/Black wire). If PCM detected MAF/IAT sensor voltage more than 4.84 volts, PCM determines MAF/IAT signal circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. MAF/IAT sensor malfunction
2. Open circuit in Blue/Black wire between MAF/IAT sensor 5-pin harness connector terminal "D" and PCM 30-pin harness connector terminal "2E"
3. Open circuit in Brown wire between MAF/IAT sensor 5-pin harness connector terminal "E" and PCM 30-pin harness connector terminal "2H"
4. PCM malfunction
5. Poor connection at MAF/IAT sensor 5-pin harness connector or PCM 30-pin harness connector
6. Short to power circuit in Blue/Black wire between MAF/IAT sensor 5-pin harness connector terminal "D" and PCM 30-pin harness connector terminal "2E"

The PCM monitors Engine Coolant Temperature (ECT) sensor signal at PCM 30-pin harness connector terminal "1M" (Light Green/Black wire). If PCM detected ECT sensor voltage less than 0.20 volt, PCM determines ECT sensor circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Connector or terminal malfunction
2. ECT sensor malfunction
3. PCM malfunction
4. Short between ECT signal circuit (Light Green/Black wire) and ECT ground circuit (Brown wire) in wire harness
5. Short to ground circuit between ECT sensor harness connector terminal "A" and PCM 30-pin harness connector terminal "1M" (Light Green/Black wire)

Scheme 18

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect For Bent Terminal - Turn ignition off. Disconnect ECT sensor 2-pin harness connector. Check for bent, damaged or corroded ECT sensor connector terminals. If no malfunction is detected, go to next step. If malfunction is present, repair terminal. After repair, go to step 7.
4. Classify ECT Sensor Malfunction Or Harness Malfunction - Connect WDS or equivalent to DLC-2. Access ECT PID. Verify ECT PID value when disconnecting ECT sensor harness connector. If ECT value changes, replace ECT sensor. After repair, go to step 7.
5. Inspect ECT Signal Circuit For Short To Ground - Turn ignition off. Disconnect PCM harness connectors. Check for continuity between ground and ECT sensor harness connector terminal "A" (Light Green/Black wire). (Scheme 19) If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Light Green/Black wire between ECT sensor harness connector and PCM 30-pin harness connector terminal "1M" or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 7.
6. Inspect ECT Circuit For Short Between Harnesses - Check for continuity between ECT sensor harness connector terminals. If continuity is not present, go to next step. If continuity is present, repair short between circuits. After repair, go to next step.
7. Verify Trouble Shooting Of DTC P0117 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm it up completely. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
8. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

The PCM monitors Engine Coolant Temperature (ECT) sensor signal at PCM 30-pin harness connector terminal "1M" (Light Green/Black wire). If PCM detected ECT sensor voltage is more than 4.58 volts, PCM determines ECT sensor circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. ECT sensor malfunction
2. Open circuit in Light Green/Black wire between ECT sensor 2-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "1M"
3. Open circuit in Brown wire between ECT sensor harness terminal "B" and PCM 30-pin harness connector terminal "2H"
4. PCM malfunction
5. Poor connection of ECT sensor or PCM connectors
6. Short to power circuit between ECT sensor harness connector terminal "A" and PCM 30-pin harness connector terminal "1M"

If PCM detects TP sensor No. 1 voltage at PCM 27-pin harness connector terminal "3M" is less than 0.2 volt after ignition is turned on, PCM determines TP circuit has a malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction conditions in first drive cycles. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available.

Possible causes are

1. Connector or terminal malfunction
2. Open circuit between throttle body 6-pin harness connector terminal "A" (Brown wire) and PCM 27-pin harness connector terminal "3M" (Brown/Yellow wire)
3. Open circuit between throttle body 6-pin harness connector terminal "B" (White wire) and PCM 27-pin harness connector terminal "3N" (Violet/Red wire)
4. Short to ground circuit between throttle body 6-pin harness connector terminal "A" (Brown wire) and PCM 27-pin harness connector terminal "3M" (Brown/Yellow wire)
5. TP sensor malfunction

Scheme 19

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Classify TP Sensor Or Harness Malfunction - Connect WDS or equivalent to DLC-2. Access TP1 PID. Disconnect throttle body 6-pin harness connector. Connect a jumper wire between throttle body 6-pin harness connector terminals "A" (Brown wire) and "B" (White wire). (Scheme 20) If voltage reading is more than 4.9 volts, go to next step. If voltage reading is not more than 4.9 volts, go to step 5.
4. Inspect TP Sensor - Turn ignition off and remove fused jumper wire. Check TP sensor operation. See «THROTTLE POSITION SENSOR»(ref-151892-S09967751312003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If TP sensor is okay, check for poor connection at throttle body 6-pin harness connector terminal "B". Repair or replace as necessary. After repair, go to step 8. If TP sensor is faulty, replace throttle body. After repair, go to step 8.
5. Inspect Power Supply Circuit Voltage At Throttle Body Connector - Turn ignition off and remove fused jumper wire. Turn ignition on, engine off. Measure voltage between ground and throttle body 6-pin harness connector terminal "B" (White wire). (Scheme 20) If 4.5-5.5 volts are present, go to next step. If 4.5-5.5 volts are not present, repair or replace open circuit between throttle body 6-pin harness connector terminal "B" (White wire) and PCM 27-pin harness connector terminal "3N" (Violet/Red wire). See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 8.
6. Verify TP1 Signal Circuit For Open Circuit - Turn ignition off. Check for continuity between throttle body 6-pin harness connector terminal "A" (Brown wire) and PCM 27-pin harness connector terminal "3M" (Brown/Yellow wire). If continuity is present, go to next step. If continuity is not present, repair open circuit or replace harness between throttle body 6-pin harness connector terminal "A" (Brown wire) and PCM 27-pin harness connector terminal "3M" (Brown/Yellow wire). After repair, go to step 8.
7. Verify TP1 Signal Circuit For Short To Ground - Check continuity between throttle body 6-pin harness connector terminal "A" and body ground. If continuity is not present, go to next step. If continuity is present, repair short circuit to ground between 6-pin harness connector terminal "A" (Brown wire) and PCM 27-pin harness connector terminal "3M" (Brown/Yellow wire). After repair, go to next step.
8. Verify Trouble Shooting Of DTC P0122 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm it up completely. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
9. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

If PCM detects TP sensor No. 1 voltage at PCM 27-pin harness connector terminal "3M" is more than 4.85 volts after ignition is turned on, PCM determines that TP circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction conditions in first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Connector or terminal malfunction
2. Open circuit between throttle body 6-pin harness connector terminal "D" (White/Blue) and PCM 27-pin harness connector terminal "3K" (Pink/Blue wire)
3. Short to constant voltage supply circuit between throttle body 6-pin harness connector terminal "A" (Brown wire) and PCM 27-pin harness connector terminal "3M" (Brown/Yellow wire)
4. Throttle Position (TP) sensor malfunction

The PCM monitors ECT sensor signal at PCM 30-pin harness connector terminal "1M" after engine is started and engine is cold. If ECT voltage does not reach expected temperature for specified period, PCM determines that it has taken an excessive amount of time for engine coolant temperature to reach temperature necessary to start closed-loop fuel control. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. ECT sensor malfunction
2. PCM malfunction
3. Poor connection of connectors

DTC P0126: If ECT signal never exceeds 160°F (71°C) after engine start for specified period, PCM determines that coolant thermostat is stuck open.

Monitoring Conditions

1. Difference between ECT at engine start and minimum IAT: Less than 43°F (6°C)
2. IAT: More than 14°F (-10°C)
3. Vehicle speed: More than 5.9 MPH

DTC P0128: PCM monitors MAF, IAT, VSS and EAT signals and calculate radiator's heat radiation ratio while following monitoring conditions are met. If calculated value exceeds threshold, PCM determines that coolant thermostat is stuck open.

Monitoring Conditions

1. Difference between ECT at engine start and minimum IAT: Less than 43°F (6°C)
2. ECT at engine start: Less than 97°F (36°C)
3. IAT: More than 14°F (-10°C)
4. Vehicle speed: More than 5.9 MPH

This is a continuous monitor (THERMOSTAT). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Coolant thermostat malfunction
2. ECT sensor malfunction
3. PCM malfunction

PCM monitors input voltage from front HO2S when following monitoring conditions are met. If input voltage from sensor remains less than or more than 0.45 volt for 41.2 seconds, PCM determines there is no front HO2S inversion.

Monitoring Conditions

1. Engine speed is more than 1500 RPM
2. Engine coolant temperature is more than 176°F (80°C)

This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Air suction or leakage
2. Engine malfunction
3. Front HO2S heater malfunction
4. Front HO2S malfunction
5. Fuel delivery hose clogging or leakage
6. Fuel filter clogging
7. Fuel injector malfunction
8. Fuel pump malfunction
9. Fuel return hose clogging or leakage
10. Ignition coil malfunction
11. Insufficient compression
12. PCV valve malfunction
13. Pressure regulator malfunction
14. Purge solenoid hoses are hooked up incorrectly
15. Purge solenoid valve malfunction

Scheme 20

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect For Other DTCs - Check for other DTCs, using WDS or equivalent. If no other DTCs are present, go to next step. If other DTCs have been stored, repair circuit malfunction for applicable DTCs. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000).
4. Identify Trigger DTC For FREEZE FRAME DATA - If DTC P0131 and P0132 are present on FREEZE FRAME DATA, go to next step. If DTC P0131 and P0132 are not present on FREEZE FRAME DATA, go to trouble shooting procedures for DTC that triggered FREEZE FRAME DATA. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000).
5. Verify Current Input Signal Status - Is Concern Intermittent Or Constant - Warm-up engine. Access O2S11 for P0131 and P0132 PID using WDS or equivalent. Verify PID value while racing engine (in PARK - ATX) or NEUTRAL - MTX). More than 0.45 volt when suddenly depressing accelerator pedal (rich condition) Less than 0.45 volt just after release of accelerator pedal (lean condition) If PID reading is okay, go to next step. If PID readings are not okay, replace front HO2S. After repair, go to step 19.
6. Inspect Long Term Fuel Trim - Access LONGFT1 for P0131 and P0132 PID using WDS or equivalent. Compare it with FREEZE FRAME DATA recorded at step 1. If PID value decreased, engine is driven under rich condition. Go to next step. If PID value did not decrease, engine is driven under lean condition. Go to step 9.
7. Inspect Fuel Line Pressure (Excessive Fuel Line Pressure) - Turn ignition off. Inspect fuel line pressure. Refer to «FUEL PRESSURE (EXCEPT B2300, B3000, B4000 & TRIBUTE)»(ref-151876-S42526614222003010800000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. If fuel line pressure is okay, go to next step. If fuel line pressure is incorrect, inspect following parts and repair or replace if necessary: Fuel pump maximum pressure Fuel return pipe for being clogged If all components are okay, replace fuel pressure regulator. After repair, go to step 19.
8. Inspect Purge Solenoid Valve For Being Stuck Open - Turn ignition off. Disconnect both hoses from purge solenoid valve. Blow air through purge solenoid valve. If air blows through, replace purge solenoid valve. After repair, go to step 19. If air does not blow through purge solenoid valve, go to step 13.
9. Inspect PCV Valve Operation - Inspect PCV valve operation. Refer to «POSITIVE CRANKCASE VENTILATION»(ref-151892-S37528392572003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If PCV valve is okay, go to next step. If PCV valve is faulty, replace PCV valve. After repair, go to step 19.
10. Inspect Fuel Line Pressure (Low Fuel Line Pressure) - Turn ignition off. Inspect fuel line pressure. Refer to «FUEL PRESSURE (EXCEPT B2300, B3000, B4000 & TRIBUTE)»(ref-151876-S42526614222003010800000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. If fuel line pressure is incorrect, go to next step. If fuel pressure is okay, go to step 13.
11. Inspect Fuel Pump Maximum Pressure - Stop engine. Turn ignition on, engine off. Perform fuel pump maximum pressure test. Refer to «FUEL PRESSURE (EXCEPT B2300, B3000, B4000 & TRIBUTE»(ref-151876-S42526614222003010800000) under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. If fuel pump maximum pressure is okay, go to next step. If fuel pump maximum pressure is incorrect, inspect fuel pump circuit for open or poor connection. Repair or replace suspected circuit. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If circuit is okay, replace fuel pump. After repair, go to step 19.
12. Inspect Fuel Line From Fuel Pump To Fuel Delivery Pump - Visually inspect fuel line for any leakage. If any fuel leakage is found, replace suspected fuel line. After repair, go to step 19. If no fuel leakage is found, inspect fuel filters for following: Restriction or clogging at fuel filter (high-pressure side) Foreign materials or stain inside fuel filter (low-pressure side) If restriction or clogging is found at fuel filter (high-pressure side), replace fuel filter. If foreign materials or stain is found inside fuel filter (low-pressure side), clean fuel tank and filter. If all items are okay, replace pressure regulator. After repair, go to step 19.
13. Check Ignition Coil Operation - Using spark tester, perform spark test. Refer to «IGNITION CHECKS»(ref-151876-S25784050672003010800000) in BASIC DIAGNOSTIC PROCEDURES article. If all cylinders do not show blinking condition, go to next step. If all cylinders show blinking condition, go to step 16.
14. Inspect Power Supply Terminal At Ignition Coil Connector - Disconnect ignition coil 3-pin harness connector. Turn ignition on, engine off. Measure voltage between ignition coil 3-pin harness connector terminal "B" (Black/White wire) and body ground. (Scheme 21) If voltage reading is battery voltage, go to next step. If voltage reading is not battery voltage, check for open circuit between ignition coil 3-pin harness connector terminal "B" (Black/White wire) and ignition switch (Blue wire). See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Repair or replace wiring harness. After repair, go to step 19.
15. Inspect Ignition Coil Resistance - Check ignition coil resistance. Refer to «COIL PACKS»(ref-151892-S18894130372003042200000) under IGNITION SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If ignition coil resistance reading is okay, go to next step. If ignition coil resistance reading is not okay, replace ignition coil. After repair, go to step 19.
16. Inspect Engine Compression - Inspect engine compression. Refer to «MECHANICAL INSPECTION»(ref-151876-S21455612632003010800000) in BASIC DIAGNOSTIC PROCEDURES article. If engine compression is okay, go to next step. If engine compression is not okay, perform engine overhaul for repairs. After repair, go to next step.
17. Inspect Fuel Injector Operation - Turn ignition off. Inspect fuel injectors. Refer to «FUEL CONTROL»(ref-151892-S35967311232003010900000) under FUEL SYSTEM in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If all fuel injectors are okay, go to next step. If any fuel injectors are not okay, replace faulty fuel injector. After repair, go to step 19.
18. Inspect Sealing Of Engine Coolant Passage - Remove radiator cap. Perform procedure to bleed air from engine coolant, then run engine at idle. If there are any small bubbles which make engine coolant white at filler opening, repair or replace faulty parts, then go to next step. If small bubbles are not present, go to next step.
19. Verify Trouble Shooting Of DTC P0131 Or P0132 Is Completed - Make sure to reconnect all disconnected connectors. Turn ignition on, engine off. Clear DTC from memory using WDS or equivalent. Start engine. Access ECT and RPM PIDs using WDS or equivalent. Make sure that ECT PID is more than 176°F (80°C). Increase and keep engine speed at more than 1500 RPM for at least one minute. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
20. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors inversion cycle period, lean-to-rich response time and rich-to-lean response time of the sensor. PCM calculates average of inversion cycle period-specified inversion cycles, average response time from lean-to-rich, and from rich-to-lean when monitoring conditions are met. If any condition exceeds threshold, PCM determines circuit has malfunction.

Monitoring Conditions

1. Calculation load 14-59 percent depends on engine speed (ATX)
2. Calculation load 20-59 percent depends on engine speed (MTX)
3. Engine coolant temperature is more than 14°F (-10°C)
4. Engine speed 1410-4000 RPM
5. Mode 3 - HO2S Heater, HO2S & TWC Repair Verification Drive Mode
6. Vehicle speed is more than 2.33 MPH

This is an intermittent monitor. (O2 sensor) MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for the same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Engine malfunction
2. Front HO2S deterioration
3. Front HO2S heater malfunction
4. Fuel filter clogged or restricted
5. Fuel leakage on fuel line from fuel distribution pipe and fuel pump
6. Fuel pump malfunction
7. Insufficient compression
8. Leakage exhaust system
9. Pressure regulator malfunction
10. Purge solenoid valve malfunction
11. Purge solenoid hoses improper connection

PCM monitors input voltage from front HO2S when following monitoring conditions are met. If input voltage from sensor never exceed 0.55 volt for 83.2 seconds, PCM determines that sensor circuit is not activated.

Monitoring Conditions

1. Engine coolant temperature is more than 176°F (80°C)
2. Engine speed is more than 1500 RPM
3. Mode 3 - HO2S Heater, HO2S & TWC Repair Verification Drive Mode

This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Engine malfunction
2. Front HO2S deterioration
3. Front HO2S heater malfunction
4. Insufficient compression
5. Leakage exhaust system
6. Open or short circuit to ground in Black wire between front HO2S 4-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "1AB"

Scheme 21

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Verify Related Pending & Stored DTCs - Turn ignition off, then on (engine off). Verify pending and stored DTCs using WDS or equivalent. If no other DTC is present, go to next step. If other DTC is present, go to appropriate DTC troubleshooting procedure for that DTC. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000).
4. Identify Trigger DTC For FREEZE FRAME DATA - If DTC P0134 is present on FREEZE FRAME DATA, go to next step. If any other DTC triggered FREEZE FRAME DATA, diagnose that DTC first. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000).
5. Verify Current Input Signal Status - Warm up engine. Access O2S11 PID using WDS or equivalent. Verify PID while racing engine (in NEUTRAL (MTX) or PARK (ATX)). More Than 0.55 volt when suddenly depressing accelerator pedal (rich condition) Less Than 0.55 volt just after release of accelerator pedal (lean condition) If PID reading is okay, go to step 8. If PID reading is not okay, go to next step.
6. Inspect Installation Of Front HO2S - Check if front HO2S is loosely installed. If front HO2S is installed securely, go to next step. If front HO2S is not installed securely, retighten front HO2S. After repair, go to step 10.
7. Inspect Gas Leakage From Exhaust System - Visually check if any gas leakage is found between exhaust manifold and front HO2S. If exhaust gas leak is not present, inspect harness for open or short to ground circuit between Front HO2S 4-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "1AB" (Black wire). (Scheme 22) Repair or replace harness if necessary. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If all items are okay, replace faulty HO2S. After repair, go to step 10.
8. Inspect Sealing Of Engine Coolant Passage - Remove radiator cap. Perform procedure to bleed air from engine coolant, then run engine at idle. If there are any small bubbles which make engine coolant white at filler opening, repair or replace faulty parts. After repair, go to next step. If small bubbles are not present, go to next step.
9. Inspect Engine Compression - Inspect engine compression. Refer to «MECHANICAL INSPECTION»(ref-151876-S21455612632003010800000) in BASIC DIAGNOSTIC PROCEDURES article. If engine compression is okay, go to next step. If engine compression is not okay, perform engine overhaul for repairs. After repair, go to next step.
10. Verify Trouble Shooting Of DTC P0134 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm it up completely. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors rear HO2S fuel trim when in closed loop fuel control. If rear HO2S fuel trim exceeds preprogrammed criteria, PCM determines circuit input is low. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Open circuit in White/Blue wire between rear HO2S 4-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "1Y"
2. Open circuit in Brown wire between rear HO2S 4-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "2H"
3. Rear HO2S malfunction
4. Short to body ground circuit in White/Blue wire between rear HO2S 4-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "1Y"

Scheme 22

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Verify Related Pending Or Stored DTCs - Turn ignition off, then on (engine off). Verify pending code or stored DTCs using WDS or equivalent. If other DTC is present, go to appropriate DTC trouble shooting procedures. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no other DTCs are present, go to next step.
4. Identify Trigger DTC For FREEZE FRAME DATA - If DTC P0137 is present on FREEZE FRAME DATA, go to next step. If any other DTC triggered FREEZE FRAME DATA, diagnose that DTC first. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000).
5. Inspect Rear HO2S Connector For Poor Connection - Turn ignition off. Disconnect rear HO2S 4-pin harness connector. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunction is not present, go to next step. If any malfunctions are present, repair terminal. After repair, go to step 11.
6. Inspect PCM Connector For Poor Connection - Disconnect PCM connectors. Check for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunctions are not present, go to next step. If any malfunctions are present, repair terminal. After repair, go to step 11.
7. Inspect Rear HO2S Signal Circuit For Open - Inspect continuity between rear HO2S 4-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "1Y" (White/Blue wire). (Scheme 23) If continuity is present, go to next step. If continuity is not present, repair or replace harness for open circuit in White/Blue wire between rear HO2S 4-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "1Y". See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 11.
8. Inspect Rear HO2S Signal Circuit For Short To Ground Circuit - Inspect continuity between rear HO2S 4-pin harness connector terminal "A" (White/Blue wire) and body ground. If continuity is present, repair short to power supply circuit in White/Blue wire between rear HO2S 4-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "1Y". After repair, go to step 11.
9. Inspect Rear HO2S Ground Circuit For Open - Check continuity between rear HO2S 4-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "2H" (Brown wire). If continuity is present, go to next step. If continuity is not present, repair open circuit in Brown wire between rear HO2S 4-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "2H". After repair, go to step 11.
10. Verify Current Input Signal Status - Start engine. Access O2S12 PID using WDS or equivalent. Verify PID while racing engine at least 10 times (in NEUTRAL (MTX) or PARK (ATX)). If PID reading stays at more than 0.45 volt, repair or replace HO2S (rear). After repair, go to next step. If PID reading does not stay at more than 0.45 volt, go to next step.
11. Verify Trouble Shooting Of DTC P0137 Is Completed - Make sure to reconnect all disconnected connectors. Turn ignition on, engine off. Clear DTC from PCM memory using WDS or equivalent. Perform «MODE 1 - PCM ADAPTIVE MEMORY PRODUCE DRIVE MODE»(ref-151885-S34300930692003010900000) and «MODE 3 - HO2S HEATER, HO2S & TWC REPAIR VERIFICATION DRIVE MODE»(ref-151885-S29276270392003010900000) under DRIVE CYCLES. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
12. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors rear HO2S fuel trim when closed loop fuel control. If rear HO2S fuel trim exceeds preprogrammed criteria, PCM determines circuit input is high. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Rear HO2S malfunction
2. Short to power circuit in Brown wire between rear HO2S 4-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "1Y"

PCM monitors input voltage from rear HO2S when following monitoring conditions are met. If input voltage from rear HO2S never exceeds 0.55 volt for 30 seconds, PCM determines sensor circuit is not activated.

Monitoring Conditions

1. Engine coolant temperature is more than 176°F (80°C)
2. Engine speed is more than 1500 RPM
3. Mode 3 - HO2S Heater, HO2S & TWC Repair Verification Drive Mode

This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Engine malfunction
2. Insufficient compression
3. Leakage exhaust system
4. Open or short to ground circuit in White/Blue wire between rear HO2S 4-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "1Y"
5. Rear HO2S deterioration
6. Rear HO2S heater malfunction

Condition

PCM monitors Short Term Fuel Trim (SHRTFT) and Long Term Fuel Trim (LONGFT) values when in closed loop fuel control. If fuel trim exceeds preprogrammed criteria, PCM determines fuel system is too lean. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction conditions during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Front HO2S deterioration
2. Front HO2S heater malfunction
3. Fuel filter clogged or restricted
4. Fuel leakage on fuel line from fuel delivery pipe and fuel pump
5. Fuel pump malfunction
6. Fuel return hose clogged
7. Insufficient compression
8. Leakage exhaust system
9. Misfire
10. Pressure regulator malfunction
11. Purge solenoid hoses improper connection
12. Purge solenoid valve malfunction
13. Variable valve timing control system improper operation

PCM monitors Short Fuel Trim (SHRTFT) and Long Fuel Trim (LONGFT) values when closed loop fuel control. If fuel trim exceeds preprogrammed criteria, PCM determines fuel system is too rich. This is a Continuous Monitor (CM). (FUEL SYSTEM) MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Front HO2S deterioration
2. Front HO2S heater malfunction
3. Fuel pump malfunction
4. Fuel return hose clogged
5. Misfire
6. PCV valve malfunction
7. Pressure regulator malfunction
8. Purge solenoid hoses - improper connection
9. Purge solenoid valve malfunction

If PCM detects Throttle Position (TP) sensor No. 2 voltage at PCM 27-pin harness connector terminal "3J" is less than 0.2 volt after ignition is turned on, PCM determines TP circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Connector or terminal malfunction
2. Open circuit between throttle body 6-pin harness connector terminal "A" (Brown wire) and PCM 27-pin harness connector terminal "3M" (Brown/Yellow wire)
3. Open circuit between throttle body 6-pin harness connector terminal "B" (White wire) and PCM 27-pin harness connector terminal "3N" (Violet/Red wire)
4. Short to ground circuit between throttle body 6-pin harness connector terminal "A" (Brown wire) and PCM 27-pin harness connector terminal "3M" (Brown/Yellow wire)
5. TP sensor malfunction

Scheme 23

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Classify TP Sensor Or Harness Malfunction - Connect WDS or equivalent. Access TP2 PID. Disconnect throttle body 6-pin harness connector. Connect fused jumper wire between throttle body 6-pin harness connector terminal "B" (White wire) and terminal "C" (Brown/Red wire). (Scheme 24) If voltage reading is more 4.9 volts, go to next step. If voltage reading is not more than 4.9 volts, go to step 5.
4. Inspect TP Sensor - Perform TP sensor inspection. Refer to «THROTTLE POSITION SENSOR»(ref-151892-S09967751312003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If TP sensor is okay, check for poor connection at throttle body 6-pin harness connector terminal "B" (White wire). Repair or replace terminal as necessary. After repair, go to step 8. If TP sensor is faulty, replace throttle body. After repair, go to step 8.
5. Inspect Power Supply Circuit Voltage At Throttle Body Connector - Turn ignition on, engine off. Measure voltage at throttle body 6-pin harness connector terminal "B" (White wire). If voltage reading is 4.5-5.5 volts, go to next step. If voltage reading is not 4.5-5.5 volts, repair or replace open circuit between throttle body 6-pin harness connector terminal "B" (White wire) and PCM 27-pin harness connector terminal "3N" (Violet/Red wire). See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 8.
6. Verify TP2 Signal Circuit For Open Circuit - Turn ignition off. Check continuity between throttle body 6-pin harness connector terminal "C" (Brown/Red wire) and PCM 27-pin harness connector terminal "3J". If continuity is present, go to next step. If continuity is not present, repair open circuit in wire harness between throttle body 6-pin harness connector terminal "C" (Brown/Red wire) and PCM 27-pin harness connector terminal "3J" (Brown/Black wire). After repair, go to step 8.
7. Verify TP2 Signal Circuit For Short To Ground - Inspect continuity between throttle body terminal "C" (Brown/Red wire) and body ground. (Scheme 24) If continuity is not present, go to next step. If continuity is present, repair or replace short circuit to ground in wire harness between throttle body 6-pin harness connector terminal "C" (Brown/Red wire) and PCM 27-pin harness connector terminal "3J" (Brown/Black wire). See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to next step.
8. Verify Trouble Shooting Of DTC P0222 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm it up completely. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
9. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors input voltage from front HO2S when following monitoring conditions are met. If input voltage from sensor never exceeds 0.55 volt for 83.2 seconds, PCM determines HO2S sensor circuit is not activated.

Monitoring Conditions

1. MODE 3 - HO2S Heater, HO2S & TWC Repair Verification Drive Mode.
2. Engine speed is more than 1500 RPM.
3. Engine coolant temperature is more than 176°F (80°C).

This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Engine malfunction
2. Front HO2S deterioration
3. Front HO2S heater malfunction
4. Insufficient compression
5. Leakage exhaust system
6. Open or short to ground in Black wire between front HO2S 4-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "1AB".

PCM monitors Crankshaft Position (CKP) sensor input signal interval time. PCM calculates change of interval time for each cylinder. If change of interval time exceeds preprogrammed criteria, PCM detects a misfire in corresponding cylinder. While engine is running, PCM counts number of misfires that occurred at 200 crankshaft revolutions and 1000 crankshaft revolutions and calculates misfire ratio for each crankshaft revolution. If ratio exceeds preprogrammed criteria, PCM determines misfire, which can damage catalytic converter or affect emission performance, has occurred. This is a Continuous Monitor (MISFIRE). MIL illuminates if PCM detects misfire which affects emission performance in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects misfire which affects emission performance during first drive cycle. MIL flashes if PCM detects misfire, which can damage catalytic converter, during first drive cycle. Therefore, PENDING CODE is not available while MIL flashes. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. CKP sensor malfunction
2. Camshaft Position (CMP) sensor malfunction
3. EGR valve malfunction
4. Excess air suction in intake air system (between Mass Airflow/Intake Air Temperature (MAF/IAT) sensor and intake manifold)
5. Fuel filter clogged
6. Fuel leakage in fuel line
7. Fuel line clogged
8. Fuel pump malfunction
9. Fuel pressure regulator malfunction
10. Fuel runout
11. High-tension lead malfunction
12. Ignition coil malfunction
13. Insufficient compression
14. MAF/IAT sensor contamination
15. PCV valve malfunction
16. Poor quality fuel
17. Purge control solenoid valve malfunction
18. Related connector and terminal malfunction
19. Related wiring harness malfunction
20. Vacuum hoses damaged or improper connection
21. Variable Valve Timing (VVT) control system improper operation

DTCS P0301, P0302, P0303 & P0304

Code Definition

1. DTC P0301: Cylinder No. 1 - Misfire Detection
2. DTC P0302: Cylinder No. 2 - Misfire Detection
3. DTC P0303: Cylinder No. 3 - Misfire Detection
4. DTC P0304: Cylinder No. 4 - Misfire Detection

PCM monitors Crankshaft Position (CKP) sensor input signal interval time. PCM calculates change of interval time for each cylinder. If change of interval time exceeds preprogrammed criteria, PCM detects a misfire in corresponding cylinder. While engine is running, PCM counts number of misfires that occurred at 200 crankshaft revolutions and 1000 crankshaft revolutions and calculates misfire ratio for each crankshaft revolution. If ratio exceeds preprogrammed criteria, PCM determines that a misfire, which can damage catalytic converter or affect emission performance, has occurred. This is a Continuous Monitor (MISFIRE). MIL illuminates if PCM detects misfire which affects emission performance in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects misfire which affects emission performance during first drive cycle. MIL flashes if PCM detects misfire which can damage catalytic converter during first drive cycle. Therefore, PENDING CODE is not available while MIL flashes. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Air suction in intake air system (between dynamic chamber and cylinder head)
2. Fuel injector malfunction
3. High-tension lead malfunction
4. Inadequate engine compression due to engine internal malfunction
5. Related connector or terminal malfunction
6. Related wiring harness malfunction
7. Spark plug malfunction

PCM monitors input signal from Knock Sensor (KS) when engine is running. If input voltage between PCM 30-pin harness connector terminals "2P" and "2S" is less than 0.9 volt, PCM determines KS circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Connector or terminal malfunction
2. KS malfunction
3. Open or short to ground circuit between KS 2-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "2S" (Yellow wire)
4. Open or short to ground circuit between KS harness connector terminal "B" and PCM 30-pin harness connector terminal "2P" (Brown wire)
5. KS wires shorted to each other

Scheme 24

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect Knock Sensor Connector Terminal For Poor Connection - Turn ignition off. Disconnect KS harness connector. Check for poor connection (such as damaged, pulled-out pins, corrosion) at KS harness connector terminal "A" (Yellow wire) and terminal "B" (Brown wire). (Scheme 25) If malfunction is not present, go to next step. If there is any malfunction present, repair or replace terminal. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 9.
4. Inspect Knock Sensor - Perform KS inspection. Refer to «KNOCK SENSOR»(ref-151892-S16389784292003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If KS is okay, go to next step. If KS is faulty, replace KS. After repair, go to step 9.
5. Inspect Knock Sensor Circuits For Open Circuit - Disconnect KS harness connector. Check for continuity between following circuits: KS harness connector female terminal "A" and PCM 30-pin harness connector terminal "2S" (Yellow wire) KS harness connector female terminal "B" and PCM 30-pin harness connector terminal "2P" (Brown wire) If continuity is present, go to next step. If continuity is not present, repair open circuit or replace suspected wire harness. After repair, go to step 9.
6. Inspect Knock Sensor Circuits For Short To Ground - Check for continuity between following circuits: KS harness connector female terminal "A" (Yellow wire) and body ground KS harness connector female terminal "B" (Brown wire) and body ground If continuity is not present, go to next step. If continuity is present, repair short circuit in suspected wire or replace wire harness After repair, go to step 9.
7. Inspect For Short Circuits - Check for continuity between KS harness connector female terminal "A" (Yellow wire) and terminal "B" (Brown wire). (Scheme 25) If continuity is not present, go to next step. If there is continuity present, repair short circuit in suspected wire or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 9.
8. Inspect PCM Connector Terminal For Poor Connection - Turn ignition off. Disconnect PCM harness connectors. Inspect for poor connection (such as damaged, pulled-out pins, corrosion) at PCM 30-pin harness connector terminal "2P" (Brown wire) and "2S" (Yellow wire). If malfunction is not present, go to next step. If any malfunction is present, repair or replace terminal. After repair, go to next step.
9. Verify Trouble Shooting Of DTC P0327 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm it up completely. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
10. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors input signal from Knock Sensor (KS) when engine is running. If input voltage between PCM 30-pin harness connector terminals "2P" and "2S" is more than 4.9 volts, PCM determines that KS circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Connector or terminal malfunction
2. KS malfunction
3. Short to power circuit in wiring between KS 2-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "2S" (Yellow wire)
4. Short to power circuit in wiring between KS harness connector terminal "B" and PCM 30-pin harness connector terminal "2P" (Brown wire)

If PCM does not receive input voltage from Crankshaft Position (CKP) sensor for 4.2 seconds while MAF is 0.26 lb/min. (2.0 grams/sec.) or more, PCM determines CKP sensor circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction conditions during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Both CKP sensor wires are shorted each other
2. CKP sensor is dirty.
3. CKP sensor malfunction
4. CKP sensor pulse wheel malfunction
5. Connector or terminal malfunction
6. Open circuit between CKP sensor 2-pin harness connector terminal "A" to PCM 30-pin harness connector terminal "2D" (Blue wire)
7. Open circuit between CKP sensor harness connector terminal "B" to PCM 30-pin harness connector terminal "2G" (Green wire)
8. Short to ground between CKP sensor harness connector terminal "A" to PCM 30-pin harness connector terminal "2D" (Blue wire)
9. Short to ground between CKP sensor harness connector terminal "B" to PCM 30-pin harness connector terminal "2G" (Green wire)
10. Short to power between CKP sensor harness connector terminal "A" to PCM 30-pin harness connector terminal "2D" (Blue wire)
11. Short to power between CKP sensor harness connector terminal "B" to PCM 30-pin harness connector terminal "2G" (Green wire)

Scheme 25

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Verify CKP Sensor Voltage - Disconnect CKP sensor 2-pin harness connector. Connect voltmeter between CKP sensor connector terminals "A" and "B". (Scheme 26) Inspect voltage in AC range while cranking engine. If any voltage reading is present, go to next step. If voltage reading is not present, go to step 9.
4. Inspect CKP Sensor Connector For Poor Connection - Verify CKP sensor harness connector is connected securely. If connector is okay, go to next step. If connector is not okay, reconnect connector securely. After repair, go to step 10.
5. Inspect CKP Circuit For Short To Power - Turn ignition off. Disconnect CKP sensor connector. (Scheme 26) Turn ignition on, engine off. Measure voltage between ground and following: CKP sensor harness connector terminal "A" (Blue wire) CKP sensor harness connector terminal "B" (Green wire) If voltage reading is not present, go to next step. If any voltage reading is present, repair short circuit to power in suspected wire or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 10.
6. Inspect CMP Circuit For Short To Ground - Check for continuity between following terminals and body ground: CKP sensor harness connector terminal "A" (Blue wire) CKP sensor harness connector terminal "B" (Green wire) If continuity is not present, go to next step. If any continuity is present, repair short to ground in suspected wire or replace wire harness. After repair, go to step 10.
7. Inspect PCM Connector For Poor Connection - Disconnect PCM harness connectors. Check for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunction is not present, go to next step. If any malfunction is present, repair terminal. After repair, go to step 10.
8. Inspect CKP Circuit For Open - Check for continuity between following terminals: CKP sensor harness connector terminal "A" and PCM 30-pin harness connector terminal "2D" (Blue wire) CKP sensor harness connector terminal "B" and PCM 30-pin harness connector terminal "2G" (Green wire) If continuity is present, go to step 10. If continuity is not present, repair open circuit in suspected wire or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 10.
9. Inspect CKP Sensor - Turn ignition off. Perform CKP sensor inspection. Refer to «CRANKSHAFT POSITION SENSOR»(ref-151892-S03434950902003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If CKP sensor is faulty, replace CKP sensor. After repair, go to next step. If CKP sensor is okay, check CKP sensor pulse wheel for damage. If CKP sensor pulse wheel is okay, go to next step. If CKP pulse wheel is damaged, replace CKP sensor pulse wheel. After repair, go to next step.
10. Verify Trouble Shooting Of DTC P0335 Completed - Make sure to reconnect all disconnected connectors. Turn ignition on, engine off. Clear DTC from PCM memory using WDS or equivalent. Start engine. Access MAF PID using WDS or equivalent. If same DTC is not present, go to next step. If same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors input voltage from Camshaft Position (CMP) sensor when engine is running. If PCM does not receive input voltage from CMP sensor while PCM receives input signal from CKP sensor, PCM determines CMP circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Both CMP sensor wires are shorted to each other
2. CKP sensor pulse wheel malfunction
3. CMP sensor is dirty
4. CMP sensor malfunction
5. Connector or terminal malfunction
6. Open circuit between CMP sensor harness connector terminal "A" and PCM 30-pin harness connector terminal "2M"
7. Open circuit between CMP sensor harness connector terminal "B" and PCM 30-pin harness connector terminal "2J"
8. Short to power circuit between CMP sensor harness connector terminal "A" and PCM 30-pin harness connector terminal "2M"
9. Short to power circuit between CMP sensor harness connector terminal "B" and PCM 30-pin harness connector terminal "2J"
10. Short to ground circuit between CMP sensor harness connector terminal "A" and PCM 30-pin harness connector terminal "2M"
11. Short to ground circuit between CMP sensor harness connector terminal "B" and PCM 30-pin harness connector terminal "2J"

Scheme 26

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Verify CMP Sensor Voltage - Disconnect CMP sensor 2-pin harness connector. Connect voltmeter between CMP sensor connector terminals "A" and "B". (Scheme 27) Inspect voltage in AC range while cranking engine. If any voltage reading is present, go to next step. If AC voltage reading is not present, go to step 9.
4. Inspect CMP Sensor Connector For Poor Connection Verify CMP sensor connector is connected securely. Is connector okay, go to next step. If connector is not okay, reconnect connector securely. After repair, go to step 10.
5. Inspect CMP Circuit For Short To Power - Turn ignition off. Disconnect CMP sensor harness connector. (Scheme 27) Turn ignition on, engine off. Measure voltage between ground and following: CMP sensor harness connector terminal "A" (Brown/White wire) CMP sensor harness connector terminal "B" (White/Violet wire) If voltage reading is not present, go to next step. If any voltage reading is present, repair short circuit to power in suspected wire or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 10.
6. Inspect CMP Circuit For Short To Ground - Check for continuity between following terminals and body ground: CMP sensor harness connector terminal "A" (Brown/White wire) CMP sensor harness connector terminal "B" (White/Violet wire) If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in suspected wire or replace wire harness. After repair, go to step 10.
7. Inspect Poor Connection Of PCM Connector - Disconnect PCM harness connectors. Check for poor connection (damaged, pulled-out terminals, corrosion, etc.). If malfunction is not present, go to next step. If there is any malfunction, repair or replace terminal. After repair, go to step 10.
8. Inspect CMP Circuit For Open Circuit - Check for continuity between following terminals: CMP sensor harness connector terminal "A" (Brown/White wire) and PCM 30-pin harness connector terminal "2M" (White wire) CMP sensor harness connector terminal "B" (White/Violet wire) and PCM 30-pin harness connector terminal "2J" (Black wire) If continuity is present, go to step 10. If continuity is not present, repair open circuit in suspect wire or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 10.
9. Inspect CMP Sensor - Turn ignition off. Perform CMP sensor inspection. Refer to «CAMSHAFT POSITION SENSOR»(ref-151892-S16315825052003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If CMP sensor is faulty, replace CMP sensor. After repair, go to next step. If CMP sensor is okay, check CMP sensor pulse wheel for damage. If CMP sensor pulse wheel is okay, go to next step. If CMP pulse wheel is damaged, replace CMP sensor pulse wheel. After repair, go to next step.
10. Verify Trouble Shooting Of DTC P0335 Completed - Make sure to reconnect all disconnected connectors. Turn ignition on, engine off. Clear DTC from PCM memory using WDS or equivalent. Start engine. Access MAF PID using WDS or equivalent. If same DTC is not present, go to next step. If same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors difference in intake manifold pressures when EGR is operated and when it is stopped. If difference is too small, PCM determines EGR flow insufficient. This is an intermittent monitor (EGR). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. EGR boost sensor malfunction
2. EGR boost sensor solenoid valve malfunction
3. EGR gasket malfunction
4. EGR valve malfunction
5. PCM malfunction

PCM monitors difference in intake manifold pressures when EGR is operated and when it is stopped. If difference is too large, PCM determines that EGR flow excessive. This is an intermittent monitor (EGR). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. EGR valve gasket has been damaged
2. EGR valve gasket is not installed
3. PCM malfunction

PCM monitors input voltage from EGR valve. If voltage at PCM terminals 4E, 4H, 4K and/or 4N remain low or high, PCM determines that EGR valve circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is not available. DTC is not stored in PCM memory.

Possible causes are

1. Connector or terminal malfunction
2. EGR valve malfunction
3. Open circuit in wiring between EGR valve 6-pin harness connector terminal "E" and PCM 30-pin harness connector terminal "4E" (Red/Green wire)
4. Open circuit in wiring between EGR valve 6-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "4H" (Pink wire)
5. Open circuit in wiring between EGR valve 6-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "4K" (Gray wire)
6. Open circuit in wiring between EGR valve 6-pin harness connector terminal "F" and PCM 30-pin harness connector terminal "4N" (Yellow wire)
7. Open circuit in wiring between main relay terminal "D" and EGR valve 6-pin harness connector terminal "C" (White wire)
8. Open circuit in wiring between main relay terminal "D" and EGR valve 6-pin harness connector terminal "D" (White wire)
9. PCM malfunction
10. Short to power circuit in wiring between EGR valve 6-pin harness connector terminal "E" and PCM 30-pin harness connector terminal "4E" (Red/Green wire)
11. Short to power circuit in wiring between EGR valve 6-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "4H" (Pink wire)
12. Short to power circuit in wiring between EGR valve 6-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "4K" (Gray wire)
13. Short to power circuit in wiring between EGR valve 6-pin harness connector terminal "F" and PCM 30-pin harness connector terminal "4N" (Yellow wire)
14. Short to ground circuit in wiring between EGR valve 6-pin harness connector terminal "E" and PCM 30-pin harness connector terminal "4E" (Red/Green wire)
15. Short to ground circuit in wiring between EGR valve 6-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "4H" (Pink wire)
16. Short to ground circuit in wiring between EGR valve 6-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "4K" (Gray wire)
17. Short to ground circuit in wiring between EGR valve 6-pin harness connector terminal "F" and PCM 30-pin harness connector terminal "4N" (Yellow wire)

Scheme 27

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect EGR Valve Connector For Poor Connection - Disconnect EGR valve 6-pin harness connector. Check for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunction is not present, go to next step. If any malfunction is present, repair terminal. After repair, go to step 10.
4. Inspect Power Circuit For Open Circuit - Turn ignition on, engine off. Measure voltage between body ground and following terminals: EGR valve 6-pin harness connector terminal "C" (White wire). EGR valve 6-pin harness connector terminal "D" (White wire). If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in suspected wire or replace wire harness. (Scheme 28) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 10.
5. Inspect EGR Valve - Perform EGR valve inspection. «EXHAUST GAS RECIRCULATION SYSTEM»(ref-151892-S39514123932003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If EGR valve is okay, go to next step. If EGR valve is faulty, replace EGR valve. After repair, go to step 10.
6. Inspect For Control Circuit For Short To Ground - Turn ignition off. Check for continuity between body ground and following terminals: EGR valve 6-pin harness connector terminal "E" (Red/Green wire) EGR valve 6-pin harness connector terminal "A" (Pink wire) EGR valve 6-pin harness connector terminal "B" (Gray wire) EGR valve 6-pin harness connector terminal "F" (Yellow wire) If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in suspected wire or replace wire harness. After repair, go to step 10.
7. Inspect For Control Circuit For Short To Power - Turn ignition on, engine off. Measure voltage between body ground and following terminals: EGR valve 6-pin harness connector terminal "E" (Red/Green wire) EGR valve 6-pin harness connector terminal "A" (Pink wire) EGR valve 6-pin harness connector terminal "B" (Gray wire) EGR valve 6-pin harness connector terminal "F" (Yellow/Green wire) If battery voltage is not present, go to next step. If battery voltage is present, repair short circuit to power in suspected wire or replace wire harness. After repair, go to next step.
8. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM harness connectors. Check for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunctions are not present, go to next step. If any malfunctions are present, repair or replace terminal. After repair, go to step 10.
9. Inspect Control Circuit For Open Circuit - Disconnect PCM harness and EGR valve connectors. Check for continuity between following terminals: Between EGR valve 6-pin harness connector terminal "E" and PCM 30-pin harness connector terminal "4E" (Red/Green wire) Between EGR valve 6-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "4H" (Pink wire) Between EGR valve 6-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "4K" (Gray wire) Between EGR valve 6-pin harness connector terminal "F" and PCM 30-pin harness connector terminal "4N" (Yellow/Green wire) If continuity is present, go to next step. If continuity is not present, repair open circuit in suspected wire or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to next step.
10. Verify Trouble Shooting Of DTC P0403 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm it up completely. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM compares number of front HO2S and rear HO2S inversions for a predetermined time. PCM monitors number of inversions rear side performs while front side inverts for a specified number of times when following Monitoring Conditions are met. PCM detects inversion ratio. If inversion ratio is less than threshold, PCM determines catalyst system has deteriorated.

Monitoring Conditions

1. Calculated load 15-50 percent (maximum calculated load value varies depending on engine speed)
2. Engine speed 1500-3000 RPM (MTX)
3. Engine speed 1410-3000 RPM (ATX)

This is an intermittent monitor (CATALYST). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Exhaust gas leakage
2. Front HO2S malfunction
3. Looseness of front HO2S
4. Looseness of rear HO2S
5. Three-Way Catalytic Converter (TWC) deterioration or malfunction

PCM measures purge line pressure, which is the vacuum when following Monitoring Conditions are present. If vacuum between charcoal canister and intake manifold does not reach specified, PCM determines EVAP system has clogging.

Monitoring Conditions

1. Engine speed: 1130-2720 RPM
2. Throttle opening angle: 10.2-25 percent
3. Vehicle speed: 24.8-49.7 MPH

This is an intermittent monitor (Evaporative system monitor). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Catch tank malfunction
2. Charcoal canister malfunction
3. EVAP hose damaged or loose
4. Evaporative emission system leak detection pump malfunction
5. EVAP pipe damaged
6. PCM malfunction
7. Purge solenoid valve malfunction

PCM measures pump load current (EVAP line pressure) when the specified period has passed after EVAP system is sealed when Monitoring Conditions are met. If load does not reach reference current value within specified period, PCM determines EVAP system has small leak.

Monitoring Conditions

1. Atmospheric pressure: 21.33 in. Hg (541.8 mm Hg) or more
2. Battery voltage: 11-14.6 volts
3. Fuel tank level: 15-85 percent
4. IAT: 41-104°F (5-40°C)
5. IG switch off

This is an intermittent monitor (Evaporative system monitor). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Catch tank malfunction
2. Charcoal canister malfunction
3. EVAP hoses damaged or loose
4. EVAP pipe damaged
5. EVAP system leak detection pump malfunction
6. Fuel filler cap malfunction
7. Fuel pump unit poor seal
8. Fuel tank components improperly installed
9. Fuel tank malfunction
10. Purge solenoid valve malfunction

PCM monitors input voltages from purge solenoid valve. If voltage at PCM 30-pin harness connector terminal "4U" remains low or high, PCM determines purge solenoid valve circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Connector or terminal malfunction
2. Open circuit in wiring between main relay and purge solenoid valve 2-pin harness connector terminal "B" (White wire)
3. Open circuit in wiring between purge solenoid valve harness connector terminal "A" and PCM 30-pin harness connector terminal "4U" (Blue/Yellow wire)
4. PCM malfunction
5. Purge solenoid valve malfunction
6. Short to ground in wiring between purge solenoid valve harness connector terminal "A" and PCM 30-pin harness connector terminal "4U" (Blue/Yellow wire)
7. Short to power circuit between purge solenoid valve harness connector terminal "A" and PCM 30-pin harness connector terminal "4U" (Blue/Yellow wire)

Scheme 28

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Classify Open Circuit Or Short To Ground Malfunction - Disconnect purge solenoid valve tube that is connected to intake manifold. Connect vacuum pump to purge solenoid valve. Pump vacuum pump several times and stop. Wait a few seconds. If vacuum is not maintained, go to next step. If vacuum is maintained, go to step 5.
4. Inspect Passage Control Of Purge Solenoid Valve - Turn ignition off. Disconnect purge solenoid valve harness connector. Pump vacuum pump several times and wait a few seconds. If vacuum is maintained, repair or replace wire harness for short to ground. After repair, go to step 10. If vacuum is not maintained, replace purge solenoid valve. After repair, go to step 10.
5. Inspect Purge Solenoid Valve Connector For Poor Connection - Turn ignition off. Inspect for poor connection (damaged/pulled-out pins, corrosion, etc.). If terminals are okay, go to next step. If malfunction is present, repair suspected terminal or replace wire harness. After repair, go to step 10.
6. Inspect Purge Solenoid Valve - Perform Purge Solenoid Valve Inspection. Refer to «PURGE SOLENOID VALVE»(ref-151892-S07758970622003010900000) under RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If purge solenoid valve is okay, go to next step. If purge solenoid valve is faulty, replace purge solenoid valve. After repair, go to step 10.
7. Inspect Purge Solenoid Valve Power Supply Circuit For Open Circuit - Turn ignition on, engine off. Measure voltage between purge solenoid valve harness connector terminal "B" (White wire) and body ground. (Scheme 29) If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in White wire between purge solenoid valve harness connector terminal "B" and Main relay or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 10.
8. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM harness connectors. Check for poor connection (damaged/pulled-out pins, corrosion, etc.). If connection is okay, go to next step. If malfunction is present, repair or replace terminal. After repair, go to step 10.
9. Inspect Purge Solenoid Valve Control Circuit - Turn ignition, on engine off. Measure voltage between purge solenoid valve harness connector terminal "A" (Blue/Yellow wire) and body ground. If battery voltage is present, repair short circuit in Blue/Yellow wire between purge solenoid valve harness connector terminal "A" and PCM 30-pin harness connector terminal "4U" or replace wire harness. After repair, go to next step. If battery voltage is not present, check for continuity in Blue/Yellow wire between purge solenoid valve harness connector terminal "A" and PCM 30-pin harness connector terminal "4U". If continuity is present, go to next step. If continuity is not present, repair open circuit in Blue/Yellow wire between purge solenoid valve harness connector terminal "A" and PCM 30-pin harness connector terminal "4U". After repair, go to next step.
10. Verify Trouble Shooting Of DTC P0443 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm it up completely. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

The PCM monitors pump load current (EVAP line pressure), while evaporative leak monitor is operating. When the decrease in pump load current is less than specification after the reference current value has been obtained, PCM determines Change Over Valve (COV) in EVAP system leak detection pump has a malfunction. This is a continuous monitor (Evaporative system monitor). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Damaged COV (in EVAP system leak detection pump)
2. Damaged PCM
3. Short to power circuit in Ornage wire between EVAP system leak detection pump 4-pin harness connector terminal "C" and PCM 27-pin harness connector terminal "3V"

PCM measures pump load current (EVAP line pressure) when specified period has passed after EVAP system is sealed when Monitoring Conditions are met. If load does not reach reference current value within specified period, PCM determines EVAP system has large leak.

Monitoring Conditions

1. Atmospheric pressure: 21.33 in. Hg (541.8 mm Hg) or more
2. Battery voltage: 11-14.6 volts
3. Fuel tank level: 15-85 percent
4. IAT: 41-104°F (5-40°C)
5. IG switch off

This is an intermittent monitor (Evaporative System Monitor). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Charcoal canister malfunction
2. EVAP hose damaged or loose
3. EVAP system leak detection pump malfunction
4. Fuel tank malfunction
5. Loose, missing or defective fuel filler cap
6. Poor connection or damaged vacuum hose
7. Purge solenoid valve malfunction

PCM measures pump load current (EVAP line pressure) when a specified period has passed after EVAP system is sealed after ignition is turned off. If load does not reach reference load value or rate of load increase lower than specified within a specified period, PCM determines EVAP system has very small leak.

Monitoring Conditions

1. Atmospheric pressure: 21.33 in. Hg (71.84 kPa) or more
2. Battery voltage: 11-14.6 volts
3. Fuel tank level: 15-85 percent
4. IAT: 41-104°F (5-40°C)
5. Ignition off

This is an intermittent monitor (Evaporative system monitor). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Catch tank malfunction
2. Change Over Valve (COV) in EVAP system leak detection pump malfunction
3. Charcoal canister malfunction
4. EVAP hose damaged or loose
5. EVAP pipe damaged
6. Fuel filler cap malfunction
7. Fuel pump unit poor seal
8. Fuel tank malfunction
9. Purge solenoid valve malfunction

PCM monitors fuel gauge sender unit input voltage difference before and after PCM-calculated fuel consumption has reached 25.9 US qt. (24.5 liters). If fuel gauge sender unit operation reflects 5 percent less than PCM-calculated fuel consumption, PCM determines fuel gauge sender unit range/performance is in error. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possibly caused by fuel gauge sender unit malfunction or substandard performance.

PCM monitors signal of fuel level and fuel gauge sender unit output voltage from instrument cluster. If PCM detects fuel level or fuel gauge sender unit output voltage is too low, PCM determines fuel gauge sender unit circuit has a malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Fuel gauge sender unit malfunction
2. Instrument cluster malfunction
3. PCM malfunction

PCM monitors signal of fuel level and fuel gauge sender unit output voltage from instrument cluster. If PCM detects fuel level or fuel gauge sender unit output voltage is too high, PCM determines fuel gauge sender unit circuit has a malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Fuel gauge sender unit malfunction
2. Instrument cluster malfunction
3. PCM malfunction

PCM monitors cooling fan relay No. 1 control signal at PCM 30-pin harness connector terminal "4L". If voltage at PCM 30-pin harness connector terminal "4L" remains low or high, PCM determines fan relay No. 1 circuit has malfunction. This is a Continuous Monitor (other). MIL does not come on. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory if PCM detects malfunction condition in two consecutive drive cycles.

Possible causes are

1. Connector or terminal malfunction
2. Cooling fan relay No. 1 malfunction
3. Open circuit in wiring between cooling fan relay No. 1 terminal "A" and PCM terminal "4L" (Red/black wire)
4. Open circuit in wiring between ignition switch and cooling fan relay No. 1 terminal "E" (Green/Black wire)
5. PCM malfunction
6. Short to ground in wiring between cooling fan relay No. 1 terminal "A" and PCM terminal "4L" (Red/Black wire)
7. Short to power circuit between cooling fan relay No. 1 terminal "A" and PCM terminal "4L" (Red/Black wire)

Scheme 29

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect Cooling Fan Relay No. 1 Connector For Poor Connection - Turn ignition off. Disconnect cooling fan relay No. 1 harness connector. Inspect for poor connection (such as damaged, pulled-out pins, corrosion, etc.). If malfunction is not present, go to next step. If malfunction is present, repair or replace suspected terminal or connector. After repair, go to step 10.
4. Inspect Cooling Fan Relay No. 1 Power Circuit For Open Circuit - Turn ignition on, engine off. Measure voltage between cooling fan relay No. 1 harness connector terminal "E" (Green/Black wire) and body ground. (Scheme 30) If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in Green/black wire between cooling fan relay No. 1 harness connector terminal "E" and ignition switch or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 10.
5. Inspect Cooling Fan Relay No. 1 - Inspect cooling fan relay No. 1. Refer to «COOLING FAN»(ref-151892-S18671099412003010900000) under MISCELLANEOUS CONTROLS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If cooling fan relay No. 1 is okay, go to next step. If cooling fan relay No. 1 is faulty, replace cooling fan relay No. 1. After repair, go to step 10.
6. Inspect Cooling Fan Relay No. 1 Control Circuit For Short To Power - Measure voltage between cooling fan relay No. 1 harness connector terminal "A" (Red/Black wire) and body ground. If battery voltage is not present, go to next step. If battery voltage is present, repair short circuit to power in Red/Black wire between cooling fan relay No. 1 harness connector terminal "A" and PCM 30-pin harness connector terminal "4L". After repair, go to step 10.
7. Inspect Cooling Fan Relay No. 1 Control Circuit For Short To Ground - Check for continuity between cooling fan relay No. 1 harness connector terminal "A" (Red/Black wire) and body ground. If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Red/Black wire between cooling fan relay No. 1 harness connector terminal "A" and PCM 30-pin harness connector terminal "4L" or replace wire harness. After repair, go to step 10.
8. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM harness connectors. Check for poor connection (such as damaged, pulled-out pins, corrosion). If terminals are okay, go to next step. If malfunction is present, repair or replace terminal/connector. After repair, go to step 10.
9. Inspect Cooling Fan Relay No. 1 Control Circuit For Open Circuit - Check for continuity between cooling fan relay No. 1 harness connector terminal "A" and PCM 30-pin harness connector terminal "4L" (Red/Black wire). (Scheme 30) If continuity is present, go to next step. If continuity is not present, repair open circuit in Red/Black wire between cooling fan relay No. 1 harness connector terminal "A" and PCM 30-pin harness connector terminal "4L" or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to next step.
10. Verify Trouble Shooting Of DTC P0480 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm it up until ECT PID more than 212°F (100°C). If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors cooling fan relay No. 2 and No. 3 control signal at PCM 30-pin harness connector terminal "4F". If voltage at PCM 30-pin harness connector terminal "4F" remains low or high, PCM determines fan relay No. 2 and No. 3 circuit has malfunction. This is a Continuous Monitor (other). MIL does not come on. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory if PCM detects malfunction condition in two consecutive drive cycles.

Possible causes are

1. Connector or terminal malfunction
2. Cooling fan relay No. 2 malfunction
3. Cooling fan relay No. 3 malfunction
4. Open circuit in wiring between cooling fan relay No. 2 harness connector terminal "E" and PCM 30-pin harness connector terminal "4F"
5. Open circuit in wiring between cooling fan relay No. 3 harness connector terminal "A" and PCM 30-pin harness connector terminal "4F"
6. Open circuit in wiring between ignition switch and cooling fan relay No. 2 harness connector terminal "A"
7. Open circuit in wiring between ignition switch and cooling fan relay No. 3 harness connector terminal "E"
8. PCM malfunction
9. Short to ground in wiring between cooling fan relay No. 2 harness connector terminal "E" and PCM 30-pin harness connector terminal "4F"
10. Short to ground in wiring between cooling fan relay No. 3 harness connector terminal "A" and PCM 30-pin harness connector terminal "4F"
11. Short to power circuit in wiring between cooling fan relay No. 2 harness connector terminal "E" and PCM 30-pin harness connector terminal "4F"
12. Short to power circuit in wiring between cooling fan relay No. 3 harness connector terminal "A" and PCM 30-pin harness connector terminal "4F"

Scheme 30

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect Cooling Fan Relay No. 2 & No. 3 Connector For Poor Connection - Turn ignition off. Disconnect cooling fan relays No. 2 and 3 harness connectors. Check for poor connection (such as damaged, pulled-out pins, corrosion). If terminals are okay, go to next step. If malfunction is present, repair or replace suspected terminal. After repair, go to step 10.
4. Inspect Cooling Fan Relay No. 2 & No. 3 Power Circuit For Open - Turn ignition on, engine off. Measure voltage in Green/Black wire between following terminals and body ground. (Scheme 31) Cooling fan relay No. 2 harness connector terminal "A" Cooling fan relay No. 3 harness connector terminal "E" If battery voltage is present at both cooling fan relay terminals, go to next step. If battery voltage is not present at both terminals, repair open circuit in Green/Black wire between ignition switch and suspected cooling fan relay terminal or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 10.
5. Inspect Cooling Fan Relays No. 2 & No. 3 - Inspect cooling fan relays No. 2 and No. 3. Refer to «COOLING FAN»(ref-151892-S18671099412003010900000) under MISCELLANEOUS CONTROLS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If cooling fan relays No. 2 and No. 3 are okay, go to next step. If cooling fan relay No. 2 or No. 3 is faulty, replace faulty cooling fan relay. After repair, go to step 10.
6. Inspect Cooling Fan Relay No. 2 & No. 3 Control Circuit For Short To Power - Measure voltage in Gray/Blue wire between following terminals and body ground. Cooling fan relay No. 2 harness connector terminal "E" Cooling fan relay No. 3 harness connector terminal "A" If battery voltage is not present, go to next step. If battery voltage is present, repair short circuit to power in Gray/Blue wire between cooling fan relays No. 2 or No. 3 and PCM 30-pin harness connector terminal "4F" or replace wire harness. After repair, go to step 10.
7. Inspect Cooling Fan Relay No. 2 & No. 3 Control Circuit For Short To Ground - Inspect continuity between following terminals and body ground. (Scheme 31) Cooling fan relay No. 2 harness connector terminal "E" Cooling fan relay No. 3 harness connector terminal "A" If continuity is present, repair short circuit to ground in Gray/Blue wire between suspected cooling fan relay No. 2 or No. 3 harness connector terminal and PCM 30-pin harness connector terminal "4F" or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 10.
8. Inspect PCM Connectors For Poor Connection - Turn ignition off. Disconnect PCM harness connectors. Check for poor connection (such as damaged, pulled-out pins, corrosion). If terminals are okay, go to next step. If malfunction is present, repair or replace terminal/connector. After repair, go to step 10.
9. Inspect Cooling Fan Relay No. 2 And No. 3 Control Circuit For Open Circuit - Check for continuity in Gray/Blue wire between following terminals and PCM 30-pin harness connector terminal "4F". Cooling fan relay No. 2 harness connector terminal "E" Cooling fan relay No. 3 harness connector terminal "A" If continuity is present, go to next step. If continuity is not present, repair open circuit in Gray/Blue wire between suspected cooling fan relay harness connector terminal and PCM 30-pin harness connector terminal "4F". After repair, go to step 10.
10. Verify Trouble Shooting Of DTC P0481 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and turn on A/C switch and fan switch. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors cooling fan relay No. 4 control signal at PCM 30-pin harness connector terminal "4B". If voltage at PCM terminal "4B" remains low or high, PCM determines that fan relay No. 4 circuit has malfunction. This is a Continuous Monitor (other). MIL does not come on. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory if PCM detects malfunction condition in two consecutive drive cycles.

Possible causes are

1. Connector or terminal malfunction
2. Cooling fan relay No. 4 malfunction
3. Open circuit in wiring between cooling fan relay No. 4 harness connector terminal "A" and PCM 30-pin harness connector terminal "4B"
4. Open circuit in wiring between ignition switch and cooling fan relay No. 4 harness connector terminal "E"
5. PCM malfunction
6. Short to ground in wiring between cooling fan relay No. 4 harness connector terminal "A" and PCM 30-pin harness connector terminal "4B"
7. Short to power circuit in wiring between cooling fan relay No. 4 harness connector terminal "A" and PCM 30-pin harness connector terminal "4B"

Scheme 31

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect Cooling Fan Relay No. 4 Connector For Poor Connection - Turn ignition off. Disconnect cooling fan relay No. 4 harness connector. Inspect for poor connection (such as damaged, pulled-out pins, corrosion, etc.). If malfunction is not present, go to next step. If malfunction is present, repair or replace suspected terminal or connector. After repair, go to step 10.
4. Inspect Cooling Fan Relay No. 4 Power Circuit For Open Circuit - Turn ignition on, engine off. Measure voltage between cooling fan relay No. 4 harness connector terminal "E" (Green/Black wire) and body ground. (Scheme 32) If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in Green/Black wire between cooling fan relay No. 4 harness connector terminal "E" and ignition switch or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 10.
5. Inspect Cooling Fan Relay No. 4 - Inspect cooling fan relay No. 4. Refer to «COOLING FAN»(ref-151892-S18671099412003010900000) under MISCELLANEOUS CONTROLS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If cooling fan relay No. 4 is okay, go to next step. If cooling fan relay No. 4 is faulty, replace cooling fan relay No. 4. After repair, go to step 10.
6. Inspect Cooling Fan Relay No. 4 Control Circuit For Short To Power - Measure voltage between cooling fan relay No. 4 harness connector terminal "A" (White/Red wire) and body ground. If battery voltage is not present, go to next step. If battery voltage is present, repair short circuit to power in White/Red wire between cooling fan relay No. 4 harness connector terminal "A" and PCM 30-pin harness connector terminal "4B". After repair, go to step 10.
7. Inspect Cooling Fan Relay No. 4 Control Circuit For Short To Ground - Check for continuity between cooling fan relay No. 4 harness connector terminal "A" (White/Red wire) and body ground. If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in White/Red wire between cooling fan relay No. 4 harness connector terminal "A" and PCM 30-pin harness connector terminal "4B" or replace wire harness. After repair, go to step 10.
8. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM harness connectors. Check for poor connection (such as damaged, pulled-out pins, corrosion). If terminals are okay, go to next step. If malfunction is present, repair or replace terminal/connector. After repair, go to step 10.
9. Inspect Cooling Fan Relay No. 4 Control Circuit For Open Circuit - Check for continuity between cooling fan relay No. 4 harness connector terminal "A" and PCM 30-pin harness connector terminal "4B" (White/Red wire). (Scheme 32) If continuity is present, go to next step. If continuity is not present, repair open circuit in White/Red wire between cooling fan relay No. 4 harness connector terminal "A" and PCM 30-pin harness connector terminal "4B" or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to next step.
10. Verify Trouble Shooting Of DTC P0482 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm it up until ECT PID more than 212°F (100°C). If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

Possible causes are

1. ABS/TCS/DCS malfunction
2. Connector or terminal malfunction
3. Open circuit between PCM 30-pin harness connector terminal "2I" and VSS 2-pin harness connector terminal "A"
4. Open circuit between PCM 30-pin harness connector terminal "2L" and VSS harness connector terminal "B"
5. PCM malfunction
6. Short to ground between PCM 30-pin harness connector terminal "2I" and VSS harness connector terminal "A"
7. Short to ground between PCM 30-pin harness connector terminal "2L" and VSS harness connector terminal "B"
8. Short to power between PCM 30-pin harness connector terminal "2I" and VSS harness connector terminal "A"
9. Short to power between PCM 30-pin harness connector terminal "2L" and VSS harness connector terminal "B"
10. VSS malfunction

Scheme 32

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Verify Current Input Signal Status - Is Concern Intermittent Or Constant - Connect WDS or equivalent to DLC-2. Start engine. Access VSS PID using WDS or equivalent. Vehicle speed: 12.4 MPH Vehicle speed: 24.8 MPH If PID readings are within specification, go to intermittent concern troubleshooting procedure. Refer to «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLE SHOOTING - NO CODES article. If PID reading are not within specification, go to next step.
4. Inspect VSS Connector For Poor Connection - Verify VSS connector is connected securely. If connection is okay, go to next step. If connector is loose, reconnect VSS harness connector securely. After repair, go to step 11.
5. Inspect VSS - Perform VSS inspection. Refer to «VEHICLE SPEED SENSOR»(ref-151892-S18953781802003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If VSS is okay, go to next step. If VSS is faulty, replace VSS. After repair, go to step 11.
6. Inspect VSS Circuit For Short To Power - Turn ignition off. Disconnect VSS harness connector. (Scheme 33) Turn ignition on, engine off. Measure voltage at following terminals: VSS harness connector terminal "A" VSS harness connector terminal "B" If voltage reading is not present at either terminal, go to next step. If any voltage reading is present, repair short circuit to power in suspected wire or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 11.
7. Inspect VSS Circuit For Short To Ground - Check for continuity between following terminals and body ground: VSS harness connector terminal "A" VSS harness connector terminal "B" If continuity is not present, go to next step. If continuity is present in either terminal, repair short circuit to ground in suspected wire or replace wire harness. After repair, go to step 11.
8. Inspect VSS Circuits For Shorts - Check for continuity between VSS harness connector terminals "A" and "B". (Scheme 33) If continuity is not present, go to next step. If continuity is present, repair short circuit or replace wire harness. After repair, go to step 11.
9. Inspect PCM Connector For Poor Connection - Disconnect PCM harness connectors. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunction is not present, go to next step. If any malfunction is present, repair suspected terminal or replace wire harness. After repair, go to step 11.
10. Inspect VSS Circuit For Open Circuit - Check for continuity between following terminals: VSS harness connector terminal "A" and PCM harness connector terminal "2I" VSS harness connector terminal "B" and PCM harness connector terminal "2L" If continuity is not present, repair open circuit in suspected wire or replace harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to next step. If continuity is present, check VSS pulse wheel for damage. If VSS pulse wheel damage is present, replace VSS pulse wheel. After repair, go to next step.
11. Verify Trouble Shooting Of DTC P0500 Is Completed - Make sure to reconnect all disconnected connectors. Turn ignition on, engine off. Clear DTC from PCM memory using WDS or equivalent. Warm up engine. Access RPM and LOAD PID using WDS or equivalent. Drive vehicle under following conditions for 18 seconds. Engine speed: 2000 RPM or more Gear: Gear is in position other than NEUTRAL Load: 40 percent or more If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
12. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM cannot control idle speed toward target idle speed while KOER self test.

Possible causes are

1. A/C relay control circuit malfunction
2. Air cleaner element clogged
3. Air intake passage clogged
4. Electronic throttle control system malfunction
5. Generator control circuit malfunction
6. Low engine compression (over capacity of blow-by gas)
7. PCM malfunction

If PCM detects actual idle speed is less than expected by 100 RPM for 14 seconds, when brake pedal is depressed (brake switch is on) and steering wheel is held straight ahead (Power Steering Pressure (PSP) switch is off), PCM determines idle control system has a malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. A/C relay control circuit malfunction
2. Air cleaner element clogged
3. Air intake passage clogged
4. Generator malfunction
5. Low engine compression (Over capacity of blow-by gas)
6. PCM malfunction
7. Purge solenoid valve malfunction

If PCM detects actual idle speed is more than expected by 200 RPM for 14 seconds, when brake pedal is depressed (brake switch is on) and steering wheel is held straight ahead (Power Steering Pressure (PSP) switch is off), PCM determines idle control system has a malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Vacuum hose misconnection
2. PCM malfunction

The PCM monitors Power Steering Pressure (PSP) switch signal at PCM 30-pin harness connector terminal "1Z" (Black/Blue wire). If input voltage is low (PSP switch stays on) for one minute when VSS is more than 37.4 MPH and ECT is more than 140°F (60°C), PCM determines PSP switch circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Connector or terminal malfunction
2. Open circuit in wiring between PSP switch single pin harness connector terminal and PCM 30-pin harness connector terminal "1Z" (Black/Blue wire)
3. PCM malfunction
4. PSP switch malfunction
5. Short to ground in wiring between PSP switch harness connector terminal and PCM 30-pin harness connector terminal "1Z" (Black/Blue wire)

Scheme 33

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect PSP Switch Connector For Poor Connection - Turn ignition off. Disconnect PSP harness connector. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If there are no malfunctions, go to next step. If there are any malfunctions, repair or replace terminal. After repair, go to step 8.
4. Inspect PSP Switch - Perform PSP switch inspection. Refer to «POWER STEERING PRESSURE SWITCH»(ref-151892-S01306177172003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If PSP switch is okay, go to next step. If PSP switch is faulty, replace PSP switch. After repair, go to step 8.
5. Inspect PSP Switch Signal Circuit For Short To Ground - Disconnect PCM connectors. Check for continuity between PSP switch harness connector terminal (Black/Blue wire) and body ground. (Scheme 34) If continuity is not present, go to next step. If continuity is present, repair short circuit in Black/Blue wire between PSP switch harness connector terminal and PCM 30-pin harness connector terminal "1Z". See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 8.
6. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM harness connectors. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If connections are okay, go to next step. If any malfunctions are present, repair or replace faulty terminal. After repair, go to step 8.
7. Inspect Signal Circuit Malfunction For Open Circuit - Check for continuity in Black/Blue wire between PSP harness connector terminal "A" and PCM 30-pin harness connector terminal "1Z". If continuity is present, go to next step. If continuity is not present, repair open circuit in Black/Blue wire between PSP switch harness connector terminal and PCM 30-pin harness connector terminal "1Z". After repair, go to step 8.
8. Verify Trouble Shooting Of DTC P0550 is Completed - Reconnect all connectors. Clear DTCs. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151885-S33082174162003010900000) under SELF-DIAGNOSTIC SYSTEM. Drive vehicle at more than 37.3 MPH for 1 minute. Verify ECT PID is more than 140°F (60°C) using WDS or equivalent. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
9. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

The PCM monitors cruise control switch signal at PCM 27-pin harness connector terminal "3P" (Red/Blue wire). If PCM detects any one of following switches (Main, CANCEL, SET/COAST, RESUME/ACCEL) remains on for 2 minutes, PCM determines cruise control switch circuit has a malfunction. This is a Continuous Monitor (other). MIL does not comes on. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Cruise control switch malfunction
2. Connector or terminal malfunction
3. PCM malfunction
4. Short to GND circuit in Red/Blue wire between cruise control switch 8-pin harness connector terminal "B" and PCM 27-pin harness connector terminal "3P".
5. Short to power circuit in Red/Blue wire between cruise control switch 8-pin harness connector terminal "B" and PCM 27-pin harness connector terminal "3P".

Scheme 34

1. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
2. Inspect Cruise Control Switch Connector For Poor Connection - Turn ignition off. Disconnect cruise control switch 8-pin harness connector. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If connections are okay, go to next step. If any malfunctions are present, repair or replace faulty terminal. After repair, go to step 6.
3. Inspect Cruise Control Switch Signal Circuit For Short To GND - Disconnect cruise control switch 8-pin harness connector and PCM harness connectors. Check for continuity between cruise control switch 8-pin harness terminal "B" (Red/Blue wire) and body GND. (Scheme 35) If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Red/Blue wire between cruise control switch 8-pin harness connector terminal "B" and PCM 27-pin harness connector terminal "3P". See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 6.
4. Inspect Cruise Control Switch Signal Circuit For Short To Power - Turn ignition on, engine off. Inspect voltage between cruise control switch 8-pin harness connector terminal "B" (Red/Blue wire) and body GND. If voltage reading is less than one volt, go to next step. If voltage reading is not less than one volt, repair short circuit to power in Red/Blue wire between cruise control switch 8-pin harness connector terminal "B" and PCM 27-pin harness connector terminal "3P". After repair, go to step 6.
5. Inspect Cruise Control Switch Operation - Inspect cruise control switch. Refer to appropriate CRUISE CONTROL SYSTEMS article in ACCESSORIES & EQUIPMENT. If cruise control switch is okay, go to next step. If cruise control switch is faulty, replace cruise control switch. After repair, go to next step.
6. Verify Trouble Shooting Of DTC P0564 Is Completed - Reconnect all connectors. Clear DTCs. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-151885-S33082174162003010900000) under SELF-DIAGNOSTIC SYSTEM. Drive vehicle using cruise control for 2 minutes or more. If same DTC is not present, go to next step. If same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
7. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

The PCM monitors changes in input voltage for brake switch No. 1 and No. 2. If PCM detects both brake switches No. 1 and No. 2 remain on or off for 15 seconds, it determines brake switch circuit has a malfunction. This is a Continuous Monitor (other). MIL does not come on. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory

Possible causes are

1. Brake switch malfunction
2. Open circuit in Green/Orange wire between brake switch 4-pin harness connector terminal "A" and PCM 27-pin harness connector terminal "3T"
3. Open circuit in Black/Orange wire between brake switch 4-pin harness connector terminal "C" and body ground
4. PCM malfunction
5. Short circuit to power in Green/Orange wire between brake switch 4-pin harness connector terminal "A" and PCM 27-pin harness connector terminal "3T"
6. Short to GND circuit in Green/Orange wire between brake switch 4-pin harness connector terminal "A" and PCM 27-pin harness connector terminal "3T"

Scheme 35

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect Brake Switch Connector For Poor Connection - Turn ignition off. Disconnect brake switch 4-pin harness connector. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If there are no malfunctions, go to next step. If there are any malfunctions, repair or replace suspected terminal. After repair, go to step 10.
4. Inspect Brake Switch - Inspect brake switch. Refer to «BRAKELIGHT SWITCH»(ref-151892-S00360292682003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If brake switch is okay, go to next step. If brake switch is faulty, replace brake switch. After repair, go to step 10.
5. Inspect GND Circuit Of Brake Switch No. 2 For Open Circuit - Check for continuity between brake switch 4-pin harness connector terminal "C" (Black/Orange wire) and body ground. (Scheme 36) If continuity is present, go to next step. If continuity is not present, repair open circuit in Black/Orange wire between brake switch 4-pin harness connector terminal "C" and ground terminal. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 10.
6. Inspect Signal Circuit Of Brake Switch No. 2 For Short To Ground - Check for continuity between brake switch 4-pin harness connector terminal "A" (Green/Orange wire) and body ground. If continuity is not present, go to next step. If continuity is present, repair short circuit in Green/Orange wire between brake switch 4-pin harness connector terminal "A" and PCM 27-pin harness connector terminal "3T". After repair, go to step 10.
7. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM harness connectors. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If connections are okay, go to next step. If any malfunctions are present, repair or replace faulty terminal. After repair, go to step 10.
8. Inspect Signal Circuit Of Brake Switch No. 2 For Open Circuit - Check for continuity in Green/Orange wire between brake switch 4-pin harness connector terminal "A" and PCM 27-pin harness connector terminal "3T". (Scheme 36) If continuity is present, go to next step. If continuity is not present, repair open circuit in Green/Orange wire between brake switch 4-pin harness connector terminal "A" and PCM 27-pin harness connector terminal "3T". See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 10.
9. Inspect Signal Circuit Of Brake Switch No. 2 For Short To Power - Turn ignition on, engine off. Measure voltage between brake switch terminal "A" (Green/Orange wire) and body ground. If battery voltage is present, repair short circuit to power in Green/Orange wire between brake switch 4-pin harness connector terminal "A" and PCM 27-pin harness connector terminal "3T". After repair, go to next step.
10. Verify Trouble Shooting Of DTC P0571 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition on, engine off. Depress and release brake pedal more than 5 times. If same DTC is not present, go to next step. If same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM internal Read Only Memory (ROM) malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. PCM internal ROM malfunction.
2. Reprogramming has not been completed properly.

No configuration data in PCM. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Complete configuration has not been completed
2. PCM malfunction

PCM internal RAM malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

1. PCM internal RAM malfunction.
2. Reprogramming has not been completed properly.

PCM internal CPU malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possibly caused by PCM internal CPU malfunction.

PCM internal malfunction. This is a Continuous Monitor (other). MIL does not illuminate. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possibly caused by PCM internal malfunction.

PCM data configuration error.

Possible causes are

1. Configuration procedure has not been completed
2. PCM malfunction

If PCM detects actual throttle opening angle is smaller or larger than target throttle opening angle, PCM determines throttle actuator control system has a malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. PCM malfunction
2. Throttle body malfunction

PCM monitors Variable Intake-air System (VIS) control solenoid valve control signal at PCM 30-pin harness connector terminal "4R". If PCM turns VIS control solenoid valve off, but voltage at PCM 30-pin harness connector terminal "4R" still remains low, PCM determines that VIS control solenoid valve circuit has malfunction.

Possible causes are

1. Connector or terminal malfunction
2. Open circuit in White wire between main relay and VIS control solenoid valve 2-pin harness connector terminal "A"
3. Open circuit in Green/Red wire between VIS control solenoid valve harness connector terminal "B" and PCM 30-pin harness connector terminal "4R"
4. PCM malfunction
5. Short to ground in Green/Red wire between VIS control solenoid valve harness connector terminal "B" and PCM 30-pin harness connector terminal "4R"
6. VIS control solenoid valve malfunction

Scheme 36

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect VIS Control Solenoid Valve Connector For Poor Connection - Turn ignition off. Disconnect VIS control solenoid valve harness connector. Inspect for poor connection (such as damaged, pulled-out pins, corrosion). If malfunction is not present, go to next step. If malfunction is present, repair or replace terminal. After repair, go to step 9.
4. Inspect VIS Control Solenoid Valve Malfunction - Perform VIS control solenoid valve inspection. «VARIABLE INTAKE-AIR SYSTEM - MAZDA6 (2.3L)»(ref-151892-S13762657662003050700000) under RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If VIS control solenoid valve is okay, go to next step. If VIS control solenoid valve is faulty, replace VIS control solenoid valve. After repair, go to step 9.
5. Inspect VIS Control Solenoid Valve Power Supply Circuit For Open Circuit - Turn ignition on, engine off. Measure voltage between VIS control solenoid valve harness connector terminal "A" (White wire) and body ground. (Scheme 37) If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in White wire between main relay and VIS control solenoid valve harness connector terminal "A". See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 9.
6. Inspect VIS Control Solenoid Valve Control Circuit For Short To Ground - Check for continuity between VIS control solenoid valve harness connector terminal "B" (Green/Red wire) and body ground. If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Green/Red wire between VIS control solenoid valve harness connector terminal "B" and PCM 30-pin harness connector terminal "4R". After repair, go to step 9.
7. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM harness connectors. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If connections are okay, go to next step. If any malfunctions are present, repair or replace faulty terminal. After repair, go to step 9.
8. Inspect VIS Control Solenoid Valve Control Circuit For Open - Check for continuity in Green/Red wire between VIS control solenoid valve harness connector terminal "B" and PCM 30-pin harness connector terminal "4R". (Scheme 37) If continuity is present, go to next step. If continuity is not present, repair open circuit in Green/Red wire between VIS control solenoid valve harness connector terminal "B" and PCM 30-pin harness connector terminal "4R". See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to next step.
9. Verify Trouble Shooting Of DTC P0661 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Start engine and increase engine speed to more than 4400 RPM a few times. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
10. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors Variable Intake-air System (VIS) control solenoid valve control signal at PCM 30-pin harness connector terminal "4R". If PCM turns VIS control solenoid valve on but voltage at PCM 30-pin harness connector terminal "4R" still remains high, PCM determines VIS control solenoid valve circuit has malfunction.

1. VIS control solenoid valve malfunction
2. Short to power circuit between VIS control solenoid valve 2-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "4R"
3. Shorted VIS control solenoid valve or PCM harness connectors
4. PCM malfunction

PCM monitors changes in input voltage from brake switch. If PCM does not detect PCM 30-pin harness connector terminal "1K" voltage changes while alternately accelerating and decelerating 8 times, PCM determines that brake switch circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

1. Brake switch malfunction
2. Open circuit in Green/Yellow wire between brake switch 4-pin harness connector terminal "D" and PCM 30-pin harness connector terminal "1K".
3. Open circuit in Green/White wire between positive battery terminal and brake switch 4-pin harness connector terminal "B".
4. PCM malfunction
5. Poor connection of brake switch or PCM harness connectors.
6. Short circuit to power in Green/Yellow wire between brake switch harness connector terminal "D" and PCM 30-pin harness connector terminal "1K".

PCM monitors changes in input voltage from clutch switch. If PCM does not detect PCM 30-pin harness connector terminal "1R" voltage changes 8 times repeatedly while running vehicle at vehicle speed less than 19 MPH, PCM determines clutch switch circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Clutch switch malfunction
2. Open circuit in Black wire between ground and clutch switch 5-pin harness connector terminal "D"
3. Open circuit in White/Green wire between clutch switch 5-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "1R"
4. PCM malfunction
5. Poor connection of clutch switch or PCM harness connectors.
6. Short to ground in White/Green wire between clutch switch 5-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "1R"

Scheme 37

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Classify High Input Or Low Input - Connect WDS or equivalent to DLC-2. Access CPP PID. Verify CPP PID during clutch pedal operation. If CPP PID is always OFF, go to next step. If CPP PID is not always OFF, go to step 7.
4. Inspect Clutch Switch Connector For Poor Connection - Turn ignition off. Disconnect clutch switch 5-pin harness connector. Check for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunction is not present, go to next step. If malfunction is present, repair or replace faulty terminal. After repair, go to step 14.
5. Classify Clutch Switch Or Circuit - Connect WDS or equivalent to DLC-2. Access CPP PID. Connect a fused jumper wire between clutch switch 5-pin harness connector terminal "B" (White/Green wire) and terminal "D" (Black wire). (Scheme 38) If CPP PID is ON, go to next step. If CPP PID is not ON, go to step 7.
6. Inspect Clutch Switch - Perform clutch switch inspection. Refer to «CLUTCH SWITCH (M/T)»(ref-151892-S16884553252003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If clutch switch is okay, go to next step. If clutch switch is faulty, replace clutch switch. After repair, go to step 14.
7. Inspect Clutch Switch Ground Circuit For Open Circuit - Inspect continuity between clutch switch 5-pin harness connector terminal "D" (Black wire) and ground. If continuity is present, go to next step. If continuity is not present, repair open circuit in Black wire between clutch switch 5-pin harness connector terminal "D" and body ground or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 14.
8. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM harness connectors. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunction is not present, go to next step. If malfunction is present, repair terminal or replace wire harness. After repair, go to step 14.
9. Inspect Clutch Switch Signal Circuit For Open Circuit - Check for continuity in White/Green wire between clutch switch 5-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "1R". (Scheme 38) If continuity is present, go to step 14. If continuity is not present, repair open circuit in White/Green wire between clutch switch 5-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "1R" or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 14.
10. Inspect Clutch Switch Connector For Poor Connection - Turn ignition off. Disconnect clutch switch 5-pin harness connector. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunction is not present, go to next step. If malfunction is present, repair terminal or replace wire harness. After repair, go to step 14.
11. Classify Clutch Switch Or Circuit - Connect WDS or equivalent to DLC-2. Access CPP PID. Verify CPP PID changes from ON to OFF when clutch switch 5-pin harness connector is disconnected. If CPP PID changes from ON to OFF, go to next step. If CPP PID does not change from ON to OFF, go to step 13
12. Inspect Clutch Switch - Perform clutch switch inspection. Refer to «CLUTCH SWITCH (M/T)»(ref-151892-S16884553252003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If clutch switch is okay, go to next step. If clutch switch is faulty, replace clutch switch. After repair, go to step 14.
13. Inspect Clutch Switch Signal Circuit For Short To Ground - Inspect continuity between clutch switch 5-pin harness connector terminal "B" and ground. If continuity is not present, go to next step. If continuity is present, repair short circuit in White/Green wire between clutch switch 5-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "1R" or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
14. Verify Trouble Shooting Of DTC P0704 Is Completed - Make sure to reconnect all disconnected connectors. Start engine. Clear DTC from PCM memory using WDS or equivalent. Operate clutch pedal 8 times repeatedly while driving vehicle less than 19 MPH. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
15. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors changes in input voltage from neutral switch. If PCM does not detect PCM 30-pin harness connector terminal "1W" voltage change from neutral switch when gears are shifted more than 14 times and vehicle speed is more than 18.6 MPH, PCM determines neutral switch circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Neutral switch malfunction
2. Open circuit in Black wire between ground and neutral switch harness connector terminal "A"
3. Open circuit in Blue/Red wire between neutral switch harness connector terminal "B" and PCM 30-pin harness connector terminal "1W"
4. PCM malfunction
5. Poor connection of neutral switch or PCM harness connectors
6. Short to ground in Blue/Red wire between neutral switch 2-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "1W"

Scheme 38

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Classify High Input Or Low Input - Connect WDS or equivalent to DLC-2. Access CPP/PNP PID. Verify CPP/PNP PID when gear in neutral position. If CPP/PNP PID is always OFF, go to next step. If CPP/PNP PID is not always OFF, go to step 7.
4. Inspect Neutral Switch Connector For Poor Connection - Turn ignition off. Disconnect neutral switch harness connector. Check for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunction is present, repair or replace terminal. After repair, go to step 14.
5. Classify Neutral Switch Or Circuit - Connect WDS or equivalent to DLC-2. Access CPP/PNP PID. Connect fused jumper wire between neutral switch harness connector terminal "A" (Black wire) and terminal "B" (Blue/Red wire). If CPP/PNP PID is ON, go to next step. If CPP/PNP PID is not ON, go to step 7.
6. Inspect Neutral Switch - Perform Neutral Switch Inspection. Refer to «NEUTRAL SWITCH (M/T)»(ref-151892-S40222397452003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If neutral switch is okay, go to step 14. If neutral switch is faulty, replace neutral switch. After repair, go to step 14.
7. Inspect Neutral Switch Ground Circuit For Open Circuit - Check for continuity between neutral switch harness connector terminal "A" (Black wire) and body ground. (Scheme 39) If continuity is present, go to next step. If continuity is not present, repair open circuit in Black wire between neutral switch harness connector and body ground. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 14.
8. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM harness connectors. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunction is not present, go to next step. If malfunction is present, repair terminal or replace wire harness. After repair, go to step 14.
9. Inspect Neutral Switch Signal Circuit For Open Circuit - Check for continuity in Blue/Red wire between neutral switch harness connector terminal "B" and PCM 30-pin harness connector terminal "1W". If continuity is present, go to step 14. If continuity is not present, repair open circuit in Blue/Red wire between neutral switch harness connector terminal "B" and PCM 30-pin harness connector terminal "1W". After repair, go to step 14.
10. Inspect Neutral Switch Connector For Poor Connection - Turn ignition off. Disconnect neutral switch harness connector. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunction is not present, go to next step. If malfunction is present, repair terminal or replace wire harness. After repair, go to step 14.
11. Classify Neutral Switch Or Circuit - Connect WDS or equivalent to DLC-2. Access CPP/PNP PID. Ensure CPP/PNP PID changes from ON to OFF when neutral switch harness connector is disconnected. If CPP/PNP PID changes from ON to OFF, go to next step. If CPP/PNP PID does not change from ON to OFF, go to step 13.
12. Inspect Neutral Switch - Perform Neutral Switch Inspection. Refer to «NEUTRAL SWITCH (M/T)»(ref-151892-S40222397452003010900000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If neutral switch is okay, go to step 14. If neutral switch is faulty, replace neutral switch. After repair, go to step 14.
13. Inspect Neutral Switch Signal Circuit For Short To Ground - Check for continuity in Blue/Red wire between neutral switch harness connector terminal "B" and body ground. (Scheme 39) If continuity is not present, go to next step. If continuity is present, repair short circuit in Blue/Red wire between neutral switch harness connector terminal "B" and PCM 30-pin harness connector terminal "1W". See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to next step.
14. Verify Trouble Shooting Of DTC P0850 Is Completed - Make sure to reconnect all disconnected connectors. Start engine. Clear DTC from PCM memory using WDS or equivalent. Start engine and let idle until normal operating temperature is reached. Drive vehicle at 18.6 MPH or more. Shift up or down 14 times during test drive. If same DTC is not present, go to next step. If same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
15. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors Variable Air Duct (VAD) control solenoid control signal at PCM 30-pin harness connector terminal "4C". If PCM detects VAD control solenoid control signal does not change when VAD control solenoid valve is switched to ON or OFF, PCM determines VAD control solenoid control circuit has malfunction. This is a Continuous Monitor (other). MIL does not comes on. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Connector or terminal malfunction
2. Open circuit in Green/White wire between VAD control solenoid valve harness connector terminal "B" and PCM 30-pin harness connector terminal "4C"
3. Open circuit in White wire between main relay and VAD control solenoid valve harness connector terminal "A"
4. PCM malfunction
5. Short circuit to ground in Green/White wire between VAD control solenoid valve 2-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "4C"
6. Short circuit to power in Green/White wire between VAD control solenoid valve harness connector terminal "B" and PCM 30-pin harness connector terminal "4C".
7. VAD control solenoid valve malfunction

Scheme 39

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Classify Power Circuit Or Control Circuit Malfunction - If same DTC and P0102, P0103, P0403, P0661, P0662, P2009 or P2010 is present, malfunction in power circuit. Go to next step. If same DTC and P0102, P0103, P0403, P0661, P0662, P2009 or P2010 is not present, malfunction is at VAD control solenoid valve or control circuit. Go to step 6.
4. Inspect VAD Control Solenoid Valve Connector For Poor Connection - Disconnect VAD control solenoid valve harness connector. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunctions are not present, go to next step. If any malfunctions are present, repair or replace terminals. After repair, go to step 12.
5. Inspect VAD Control Solenoid Valve Power Circuit For Open Circuit - Turn ignition on, engine off. Measure voltage between VAD control solenoid valve harness connector terminal "A" (White wire) and body ground. (Scheme 40) If battery voltage is present, inspect VAD control solenoid valve. If VAD control solenoid valve is faulty, replace VAD solenoid valve. After repair, go to step 12. If VAD control solenoid valve is okay, go to step 13. If battery voltage is not present, repair open in power circuit (White wire) between VAD control solenoid valve harness connector terminal "A" and main relay or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 12.
6. Inspect VAD Control Solenoid Valve Connector For Poor Connection - Disconnect VAD control solenoid valve harness connector. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunctions are not present, go to next step. If any malfunctions are present, repair or replace terminals. After repair, go to step 12.
7. Inspect VAD Control Solenoid Valve - Perform VAD control solenoid valve inspection. Refer to «VARIABLE AIR DUCT SYSTEM - MAZDA6»(ref-151892-S25815000922003052000000) under RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If VAD control solenoid valve is okay, go to next step. If VAD control solenoid valve is faulty, replace VAD control solenoid valve. After repair, go to step 12.
8. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM harness connectors. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunction is not present, go to next step. If malfunction is present, repair terminal or replace wire harness. After repair, go to step 12.
9. Inspect Control Circuit For Short To Ground - Disconnect battery cables. Check for continuity in Green/White wire between VAD control solenoid valve harness connector terminal "B" (Green/White wire) and body ground. (Scheme 40) If continuity is not present, go to next step. If continuity is present, repair or replace wire harness for short circuit to ground in Green/White wire between VAD control solenoid valve harness connector terminal "B" and PCM 30-pin harness connector terminal "4C". See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 12.
10. Inspect VAD Control Solenoid Valve Control Circuit For Short To Power - Measure voltage between VAD control solenoid valve harness connector terminal "B" (Green/White wire) and body ground. If battery voltage is not present, go to next step. If battery voltage is present, repair or replace wire harness for short circuit to power in Green/White wire between VAD control solenoid valve harness connector terminal "B" and PCM 30-pin harness connector terminal "4C". After repair, go to step 12.
11. Inspect Control Circuit For Open Circuit - Check for continuity in Green/White wire between VAD control solenoid valve harness connector terminal "B" and PCM 30-pin harness connector terminal "4C". If continuity is present, go to next step. If continuity is not present, repair open circuit in Green/White wire between VAD control solenoid valve harness connector terminal "B" and PCM 30-pin harness connector terminal "4C". After repair, go to step 12.
12. Verify Trouble Shooting Of DTC P1410 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Access RPM ECT and TP_REL PIDs. Start engine and warm up until ECT PID is 158°F (70°C) or more. Race engine a few times with following: RPM PID more than 5800 RPM TP_REL PID more than 50 percent Retrieve DTCs. If PENDING CODE of smae DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
13. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

The PCM monitors voltage of Back-up Battery (BB) positive terminal at PCM 30-pin harness connector terminal "2Z". If PCM detected BB positive terminal voltage less than 2.5 volts for 2 seconds, PCM determines BB voltage circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Melt down of EEC fuse (7.5-amp)
2. Open circuit in White/Black wire between EEC fuse (7.5-amp) and PCM 30-pin harness connector terminal "2Z"
3. PCM malfunction
4. Poor connection of PCM connectors
5. Short circuit to ground in White/Black wire between EEC fuse (7.5-amp) and PCM 30-pin harness connector terminal "2Z"

Scheme 40

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect EEC Fuse - Turn ignition off. Inspect EEC fuse (7.5-amp) for failure and proper installation. If fuse is okay, go to next step. If fuse is faulty or improperly installed: If EEC fuse has been melted down, replace fuse. After repair, go to step 4. If EEC fuse is not installed correctly, install it correctly. After repair, go to step 7.
4. Inspect Monitor Circuit For Short To Ground - Disconnect battery cables. Check for continuity in White/Black wire between EEC fuse (7.5-amp) terminal and body ground. (Scheme 41) If continuity is not present, go to next step. If continuity is present, repair or replace harness for short circuit to ground in White/Black wire between EEC fuse (7.5-amp) and PCM 30-pin harness connector terminal "2Z". See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Install NEW fuse. After repair, go to step 7.
5. Inspect PCM Connector For Poor Connection - Turn ignition off. Disconnect PCM harness connectors. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunction is not present, go to next step. If malfunction is present, repair terminal or replace wire harness. After repair, go to step 7.
6. Inspect Monitor Circuit For Open Circuit - Disconnect battery cables. Check for continuity between EEC fuse (7.5-amp) terminal and PCM 30-pin harness connector terminal "2Z". If continuity is present, go to next step. If continuity is not present, repair open circuit in Black/White wire between EEC fuse (7.5-amp) terminal and PCM 30-pin harness connector terminal "2Z" or replace wire harness. After repair, go to next step.
7. Verify Trouble Shooting Of DTC P1562 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm up completely. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
8. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors Variable Tumble Control System (VTCS) shutter valve position using VTCS shutter valve switch. If PCM turns VTCS solenoid valve on but VTCS position still remains open (VTCS shutter valve switch off), PCM determines VTCS shutter valve has been stuck open. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Misconnection or pulled out vacuum hose
2. PCM malfunction
3. VTCS shutter valve actuator malfunction (stuck open)
4. VTCS shutter valve malfunction

PCM monitors VTCS shutter valve position using VTCS shutter valve switch. If PCM turns VTCS solenoid valve off but VTCS position still remains closed (VTCS shutter valve switch is on), PCM determines that VTCS shutter valve has been stuck closed. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. CKP sensor malfunction.
2. ECT sensor malfunction.
3. PCM malfunction.
4. Short circuit to ground Blue/Orange wire between VTCS solenoid valve 2-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "4T".
5. TP sensor malfunction.
6. VTCS shutter valve actuator malfunction (stuck closed).
7. VTCS shutter valve malfunction (stuck closed).
8. VTCS solenoid valve malfunction.

PCM monitors Variable Tumble Control System (VTCS) solenoid valve control signal at PCM 30-pin harness connector terminal "4T". If PCM turns VTCS solenoid valve off but voltage at PCM 30-pin harness connector terminal "4T" still remains low, PCM determines VTCS solenoid valve circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Open circuit in White wire between main relay and VTCS solenoid valve 2-pin harness connector terminal "A"
2. Open circuit in Blue/Orange wire between VTCS solenoid valve harness connector terminal "B" and PCM 30-pin harness connector terminal "4T"
3. PCM malfunction
4. Poor connection of connectors at PCM and/or VTCS control solenoid valve
5. Short circuit to ground in Blue/Orange wire between VTCS solenoid valve harness connector terminal "B" and PCM 30-pin harness connector terminal "4T"
6. VTCS solenoid valve malfunction

Scheme 41

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect VTCS Solenoid Valve Connector For Poor Connection - Turn ignition off. Inspect for poor connection (such as damaged, pulled-out pins, corrosion). If malfunction is not present, go to next step. If malfunction is present, repair or replace terminal. After repair, go to step 9.
4. Inspect VTCS Solenoid Valve - Perform VTCS Solenoid Valve Inspection. Refer to «VARIABLE TUMBLE CONTROL SYSTEM - MAZDA6 (2.3L)»(ref-151892-S13630147152003050700000) under AIR INDUCTION SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If VTCS solenoid valve is okay, go to next step. If VTCS solenoid valve is faulty, replace VTCS solenoid valve. After repair, go to step 9.
5. Inspect VTCS Solenoid Valve Power Supply Circuit For Open Circuit - Disconnect VTCS solenoid valve harness connector. Turn ignition on, engine off. Measure voltage between VTCS solenoid valve harness connector terminal "A" and body ground. (Scheme 42) If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in White wire between VTCS solenoid valve harness connector terminal "A" and main relay or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 9.
6. Inspect PCM Connector For Poor Connection - Inspect for poor connection (such as damaged, pulled-out terminals, corrosion) at PCM 30-pin harness connector terminal "4T" (Blue/Orange wire). If malfunction is not present, go to next step. If malfunction is present, repair or replace terminal. After repair, go to next step.
7. Inspect VTCS Solenoid Valve Control Circuit For Short To Ground - Check for continuity between VTCS solenoid valve harness connector terminal "B" (Blue/Orange wire) and body ground. If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Blue/Orange wire between VTCS solenoid valve harness connector terminal "B" and PCM 30-pin harness connector terminal "4T". After repair, go to step 9.
8. Inspect VTCS Solenoid Valve Control Circuit For Open Circuit - Connect VTCS solenoid valve harness connector. Turn ignition on, engine off. Measure voltage between PCM 30-pin harness connector terminal "4T" (Blue/Orange wire) and body ground. (Scheme 42) If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit between PCM 30-pin harness connector terminal "4T" and VTCS solenoid valve harness connector terminal "B". See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to next step.
9. Verify Trouble Shooting Of DTC P2009 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm up completely. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
10. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors Variable Tumble Control System (VTCS) solenoid valve control signal at PCM 30-pin harness connector terminal "4T". If PCM turns VTCS solenoid valve on but voltage at PCM 30-pin harness connector terminal "4T" still remains high, PCM determines VTCS solenoid valve circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Poor connection of connectors at PCM and/or VTCS solenoid valve
2. Short circuit to power in Blue/Orange wire between VTCS solenoid valve 2-pin harness connector terminal "B" and PCM 30-pin harness terminal "4T"
3. VTCS solenoid valve malfunction
4. PCM malfunction

PCM monitors Oil Control Valve (OCV) voltage. If PCM detects OCV control voltage (calculated from OCV) is less than threshold voltage (calculated from battery positive voltage), PCM determines OCV circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. OCV malfunction
2. Open circuit in White wire between main relay and OCV 2-pin harness connector terminal "B"
3. Open circuit in Brown/Yellow wire between OCV harness connector terminal "A" and PCM 30-pin harness connector terminal "4M"
4. PCM malfunction
5. Poor connection of harness connectors at PCM and/or OCV
6. Short circuit to ground in Brown/Yellow wire between OCV harness connector terminal "A" and PCM 30-pin harness connector terminal "4M"

Scheme 42

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect OCV Connector For Poor Connection - Disconnect OCV harness connector. Inspect for poor connection (such as damaged, pulled-out pins, corrosion). If malfunction is not present, go to next step. If malfunction is present, repair or replace terminal. After repair, go to step 9.
4. Inspect OCV - Perform OCV Inspection. Refer to «OIL CONTROL VALVE - MAZDA6 & MIATA ONLY»(ref-151892-S39070078312003010900000) under VARIABLE VALVE TIMING in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If OCV is okay, go to next step. If OCV is faulty, replace OCV. After repair, go to step 9.
5. Inspect OCV Power Supply Circuit For Open Circuit - Disconnect OCV harness connector. Turn ignition on, engine off. Measure voltage between OCV harness connector terminal "B" (White wire) and body ground. (Scheme 43) If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in White wire between OCV harness connector terminal "B" and main relay. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 9.
6. Inspect PCM Connector For Poor Connection - Disconnect PCM harness connectors. Inspect for poor connection (such as damaged, pulled-out terminals, corrosion) at PCM 30-pin harness connector terminal "4M" (Brown/Yellow wire). If malfunction is not present, go to next step. If malfunction is present, repair or replace terminal. After repair, go to step 9.
7. Inspect OCV Control Circuit For Short To Ground - Check for continuity between OCV harness connector terminal "A" (Brown/Yellow wire) and body ground. If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Brown/Yellow wire between OCV harness connector terminal "A" and PCM 30-pin harness connector terminal "4M". After repair, go to step 9.
8. Inspect OCV Control Circuit For Open Circuit - Connect OCV harness connector. Turn ignition on, engine off. Check for continuity in Brown/Yellow wire between OCV harness connector terminal "A" and PCM 30-pin harness connector terminal "4M". (Scheme 43) If continuity is not present, go to next step. If continuity is present, repair open circuit in Brown/Yellow wire between OCV harness connector terminal "A" and PCM 30-pin harness connector terminal "4M". See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to next step.
9. Verify Trouble Shooting Of DTC P2088 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm up completely. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
10. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors OCV voltage. If PCM detects OCV control voltage (calculated from OCV) is more than threshold voltage (calculated from battery positive voltage), PCM determines OCV circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible cause are

1. OCV malfunction
2. PCM malfunction
3. Poor connection of harness connectors at PCM and/or OCV
4. Short circuit to power in Brown/Yellow wire between OCV harness connector terminal "A" and PCM 30-pin harness connector terminal "4M"

PCM monitors electronic throttle valve motor current. If PCM detects electronic throttle valve motor current is less than threshold current, PCM determines electronic throttle valve motor circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

1. Open circuit between throttle body 6-pin harness connector terminal "E" (Black wire) and PCM 30-pin harness connector terminal "4AB" (Blue/White wire)
2. Open circuit between throttle body 6-pin harness connector terminal "F" (White/Green wire) and PCM 30-pin harness connector terminal "4Y" (Blue/Black wire)
3. PCM malfunction
4. Poor connection of throttle body or PCM harness connectors
5. Short to ground circuit between throttle body 6-pin harness connector terminal "F" (White/Green wire) and PCM 30-pin harness connector terminal "4Y" (Blue/Black wire)
6. Short to ground circuit between throttle body 6-pin harness connector terminal "E" (Black wire) and PCM 30-pin harness connector terminal "4AB" (Blue/White wire)
7. Short to power between throttle body 6-pin harness connector terminal "E" (Black wire) and PCM 30-pin harness connector terminal "4AB" (Blue/White wire)
8. Throttle valve motor malfunction

Scheme 43

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Classify Intermittent Or Continuous Concern - Clear DTC using WDS or equivalent. Start engine and let idle. If same PENDING CODE is present, go to next step. If same PENDING CODE is not present, problem is intermittent. Refer to «INTERMITTENTS»(ref-151888-S02099367392003010900000) in TROUBLE SHOOTING - NO CODES article.
4. Inspect Throttle Body Connector For Poor Connection - Turn ignition off. Disconnect throttle body 6-pin harness connector. Check for poor connection (such as damaged, pulled out terminals, corrosion). If malfunctions are not present, go to next step. If malfunctions are present, repair or replace terminals. After repair, go to step 13.
5. Inspect Throttle Valve Electrical Malfunction - Measure resistance between throttle body 6-pin connector terminals "E" and "F" (part-side). If resistance reading is about 1.3 ohms, go to next step. If resistance reading is not about 1.3 ohms, replace throttle body. After repair, go to step 13.
6. Classify Malfunction In Power Supply Circuit Or Control Circuit - Turn ignition on, engine off. Measure voltage between throttle body 6-pin harness connector terminal "F" (White/Green wire) and body ground. (Scheme 44) If battery voltage is not present, malfunction is in power supply circuit. Go to next step. If battery voltage is present, malfunction is in PCM. Go to step 9.
7. Inspect Power Circuit For Short To Ground - Turn ignition off. Check for continuity between throttle body 6-pin harness connector terminal "F" (White/Green wire) and body ground. If continuity is not present, go to next step. If continuity is present, repair short to ground in power circuit between throttle body 6-pin harness connector terminal "F" (White/Green wire) and PCM 30-pin harness connector terminal "4Y" (Blue/Black wire) or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 13.
8. Inspect Power Circuit For Open - Turn ignition off. Check for continuity between throttle body 6-pin harness connector terminal "F" (White/Green wire) and PCM 30-pin harness connector terminal "4Y" (Blue/Black wire). If continuity is present, go to next step. If continuity is not present, repair open in power circuit between throttle body 6-pin harness connector terminal "F" (White/Green wire) and PCM 30-pin harness connector terminal "4Y" (Blue/Black wire) or replace wire harness. After repair, go to step 13.
9. Inspect PCM Connector For Poor Connection - Inspect for poor connection (such as damaged, pulled-out terminals, corrosion) at PCM 30-pin harness connector. If malfunction is not present, go to next step. If malfunction is present, repair or replace terminal. After repair, go to step 13.
10. Inspect Control Circuit For Short To Power - Turn ignition on, engine off. Measure voltage between throttle body 6-pin harness connector terminal "E" (Black wire) and body ground. (Scheme 44) If battery voltage is present, repair or replace wire harness for short circuit to power between throttle body 6-pin harness connector terminal "E" (Black wire) and PCM 30-pin harness connector terminal "4AB" (Blue/White wire) or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 13.
11. Inspect Control Circuit For Short To Ground - Turn ignition off. Check for continuity between throttle body 6-pin harness connector terminal "E" (Black wire) and body ground. If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in control circuit between throttle body 6-pin harness connector terminal "E" (Black wire) and PCM 30-pin harness connector terminal "4AB" (Blue/White wire) or replace wire harness. After repair, go to step 13.
12. Inspect Control Circuit Malfunction For Open Circuit - Check for continuity between throttle body 6-pin harness connector terminal "E" (Black wire) and PCM terminal "4AB" (Blue/White wire). If continuity is present, go to next step. If continuity is not present, repair open circuit between throttle body 6-pin harness connector terminal "E" (Black wire) and PCM terminal "4AB" (Blue/White wire) or replace wire harness. After repair, go to next step.
13. Verify Trouble Shooting Of DTC P2100 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm up completely. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
14. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

If PCM detects any of the following conditions, PCM determines throttle circuit has malfunction.

1. Default throttle angle that PCM memorized and throttle angle with ET control relay OFF is not much
2. PCM detects big voltage difference between from ET control relay and from main relay
3. PCM internal malfunction
4. Voltage from ET control relay is too high or too low

This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction conditions in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

1. ET control relay and related circuit malfunction
2. Main relay and related circuit malfunction
3. Throttle Position (TP) sensor No. 1 and related circuit malfunction
4. TP sensor No. 2 and related circuit malfunction
5. PCM malfunction

PCM monitors the throttle actuator circuit current. If PCM detects throttle actuator circuit current excessively low, PCM determines throttle actuator circuit malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Open circuit between throttle body 6-pin harness connector terminal "E" and PCM 30-pin harness connector terminal "4AB" (Blue/White wire)
2. Open circuit between throttle body 6-pin harness connector terminal "F" (White/Green wire) and PCM 30-pin harness connector terminal "4Y" (Blue/Black wire)
3. PCM malfunction
4. Poor connection of throttle body or PCM harness connector
5. Short circuit to ground between throttle body 6-pin harness connector terminal "E" and PCM 30-pin harness connector terminal "4AB" (Blue/White wire)
6. Short to ground circuit between throttle body 6-pin harness connector terminal "F" (White/Green wire) and PCM 30-pin harness connector terminal "4Y" (Blue/Black wire)
7. Throttle valve motor malfunction

PCM monitors throttle actuator circuit current. If PCM detects throttle actuator circuit current is excessively high, PCM determines electronic throttle actuator circuit malfunction. This is a Continuous Monitor (other). MIL illuminates if PCM detects malfunction conditions during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

1. PCM malfunction
2. Short circuit to power between throttle body 6-pin harness connector terminal "E" (Black wire) and PCM 30-pin harness connector terminal "4AB" (Blue/White wire)
3. Throttle valve motor malfunction

If PCM detects any of following conditions, PCM determines throttle actuator control module processor has malfunction.

1. Electronic throttle control has malfunction
2. Target throttle opening angle is more than actual throttle opening angle

This is an intermittent monitor. MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possibly caused by a PCM malfunction.

If PCM detects either of following conditions, PCM determines throttle actuator control system has malfunction.

1. TP sensor power supply voltage less than 4.4 volts
2. TP sensor No. 1 output voltage less than 0.20 volt or more than 4.85 volts (DTC P0122 or P0123)
3. TP sensor No. 2 output voltage less than 0.20 volt or more than 4.85 volts (DTC P0222 or P0223)
4. PCM internal circuit for TP sensor No. 1 input circuit malfunction
5. Wrong communication between main CPU and throttle control system (CPU is an internal part of PCM)

This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction conditions during first drive cycle or in two consecutive drive cycles. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Connector or terminal malfunction
2. Open circuit between throttle body 6-pin harness connector terminal "F" (White/Green wire) and PCM 30-pin harness connector terminal "4Y" (Brown/Black wire)
3. Open circuit between throttle body 6-pin harness connector terminal "D" (White/Blue wire) and PCM 27-pin harness connector terminal "3K" (Pink/Blue wire)
4. Short to ground circuit between throttle body 6-pin harness connector terminal "D" (White/Blue wire) and PCM 27-pin harness connector terminal "3K" (Pink/Blue wire)
5. Open circuit between throttle body 6-pin harness connector terminal "E" (Black wire) and PCM 30-pin harness connector terminal "4AB" (Blue/White wire)
6. Open circuit between throttle body 6-pin harness connector terminal "C" (Brown/Red wire) and PCM 27-pin harness connector terminal "3J" (Brown/Black wire)
7. PCM malfunction
8. Short to constant voltage supply circuit between throttle body 6-pin harness connector terminal "C" (Brown/Red wire) and PCM 27-pin harness connector terminal "3J" (Brown/Black wire)
9. Short to constant voltage supply circuit between throttle body 6-pin harness connector terminal "F" (White/Green wire) and PCM 30-pin harness connector terminal "4Y" (Brown/Black wire)
10. Short to ground circuit between throttle body 6-pin harness connector terminal "C" (Brown/Red wire) and PCM 27-pin harness connector terminal "3J" (Brown/Black wire)
11. Short to ground circuit between throttle body 6-pin harness connector terminal "F" (White/Green wire) and PCM 30-pin harness connector terminal "4Y" (Brown/Black wire)
12. TP sensor No. 1 malfunction
13. TP sensor No. 2 malfunction

If PCM detects actual throttle angle signal voltage is more than default throttle angle voltage after turning ignition off, PCM determines throttle actuator control on throttle body has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction conditions in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. PCM malfunction
2. Throttle valve return spring (in throttle body) broken
3. Throttle valve stuck

PCM monitors Accelerator Pedal Position (APP) sensor No. 1 signal at PCM 27-pin harness connector terminal "3D". If PCM detected APP sensor No. 1 voltage was less than 0.2 volt, PCM determines APP sensor No. 1 circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. APP sensor malfunction
2. Connector or terminal malfunction
3. Open circuit in Gray wire between APP sensor 6-pin harness connector terminal "D" and PCM 27-pin harness connector terminal "3G"
4. Open circuit in White wire between APP sensor 6-pin harness connector terminal "F" and PCM 27-pin harness connector terminal "3D"
5. Short to ground circuit in White wire between APP sensor 6-pin harness connector terminal "F" and PCM 27-pin harness connector terminal "3D"

Scheme 44

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Classify APP Sensor Or Harness Malfunction - Connect WDS or equivalent. Access APP1 PID. Disconnect throttle body 6-pin harness connector. Connect fused jumper wire between APP sensor 6-pin harness connector terminals "D" (Gray wire) and "F" (White wire). (Scheme 45) If APP1 PID reading is about 100 percent, go to next step. If APP1 PID reading is not about 100 percent, go to step 5.
4. Inspect APP Sensor - Perform APP sensor inspection. Refer to «ACCELERATOR PEDAL POSITION SENSOR»(ref-151892-S30951181632003050700000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If APP sensor is okay, inspect for poor APP sensor 6-pin connector terminal "D" connection. Repair or replace as necessary. After repair, go to step 8. If APP sensor is faulty, replace APP sensor. After repair, go to step 8.
5. Inspect Power Supply Circuit Voltage At APP Sensor Connector - Turn ignition on, engine off. Measure voltage at APP sensor 6-pin harness connector terminal "D" (Gray wire). If voltage reading is 4.5-5.5 volts, go to next step. If voltage reading is not 4.5-5.5 volts, repair open circuit in Gray wire between APP sensor 6-pin harness connector terminal "D" and PCM 27-pin harness connector terminal "3G" or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 8.
6. Verify APP1 Signal Circuit For Open Circuit - Turn ignition off. Check for continuity in White wire between APP sensor 6-pin harness connector terminal "F" and PCM 27-pin harness connector terminal "3D". If continuity is present, go to next step. If continuity is not present, repair open circuit in White wire between APP sensor 6-pin harness connector terminal "F" and PCM 27-pin harness connector terminal "3D" or replace wire harness. After repair, go to step 8.
7. Verify APP1 Signal Circuit For Short To Ground - Check for continuity between APP sensor 6-pin harness connector terminal "F" and body ground. Is continuity is not present, go to next step. If continuity is present, repair short circuit to ground in White wire between APP sensor 6-pin harness connector terminal "F" and PCM 27-pin harness connector terminal "3D" or replace wire harness. After repair, go to next step.
8. Verify Trouble Shooting Of DTC P2122 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm up completely. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
9. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

The PCM monitors Accelerator Pedal Position (APP) sensor No. 1 signal at PCM 27-pin harness connector terminal "3D" (White wire). If PCM detected APP sensor No. 1 voltage reading was more than 4.5 volts, PCM determines APP sensor No. 1 circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. APP sensor malfunction
2. Connector or terminal malfunction
3. Open circuit in Red/Green wire between APP sensor 6-pin harness connector terminal "E" and PCM 27-pin harness connector terminal "3A"
4. Open circuit in White wire between APP sensor 6-pin harness connector terminal "F" and PCM 27-pin harness connector terminal "3D"
5. Short to constant voltage supply circuit in White wire between APP sensor 6-pin harness connector terminal "F" and PCM 27-pin harness connector terminal "3D"

PCM monitors Accelerator Pedal Position (APP) sensor No. 2 signal at PCM 30-pin harness connector terminal "2A". If PCM detected APP sensor No. 2 voltage reading is less than 0.2 volt, PCM determines APP sensor No. 2 circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. APP sensor malfunction
2. Connector or terminal malfunction
3. Open circuit in Blue/Yellow wire between APP sensor 6-pin harness connector terminal "C" and PCM 30-pin harness connector terminal "2A"
4. Open circuit in Red/Black wire between APP sensor 6-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "2K"
5. Short circuit to ground in Blue/Yellow wire between APP sensor 6-pin harness connector terminal "C" and PCM 30-pin harness connector terminal "2A"

Scheme 45

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Classify APP Sensor Or Harness Malfunction - Connect WDS or equivalent. Access APP2 PID. Disconnect APP sensor 6-pin harness connector. Connect a jumper wire between APP sensor 6-pin harness connector terminal "A" (Red/Block wire) and "C" (Blue/Yellow wire). (Scheme 46) If PID value is about 100 percent, go to next step. If PID value is not about 100 percent, go to step 5.
4. Inspect APP Sensor - Perform APP Sensor Inspection. Refer to «ACCELERATOR PEDAL POSITION SENSOR»(ref-151892-S30951181632003050700000) under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If APP sensor is okay, go to next step. If APP sensor is faulty, replace APP sensor. After repair, go to step 8.
5. Inspect Power Supply Circuit Voltage At APP Sensor Connector - Turn ignition on, engine off. Measure voltage at APP sensor 6-pin harness connector terminal "A" (Red/Black wire). If voltage reading is 4.5-5.5 volts, go to next step. If voltage reading is not 4.5-5.5 volts, repair open circuit in Red/Black wire between APP sensor 6-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "2K" or replace wire harness. After repair, go to step 8.
6. Verify APP2 Signal Circuit For Open Circuit - Turn ignition off. Check for continuity Blue/Yellow wire between APP sensor 6-pin harness connector terminal "C" and PCM 30-pin harness connector terminal "2A". (Scheme 46) If continuity is present, go to next step. If continuity is not present, repair open circuit in Blue/Yellow wire between APP sensor 6-pin harness connector terminal "C" and PCM 30-pin harness connector terminal "2A" or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 8.
7. Verify APP2 Signal Circuit For Short To Ground - Check for continuity between APP sensor 6-pin harness connector terminal "C" (Blue/Yellow wire) and body ground. If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Blue/Yellow wire between APP sensor 6-pin harness connector terminal "C" and PCM 30-pin harness connector terminal "2A" or replace wire harness. After repair, go to next step.
8. Verify Trouble Shooting Of DTC P2127 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm up completely. If same DTC is not present, go to next step. If same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
9. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

The PCM monitors Accelerator Pedal Position (APP) sensor No. 2 signal at PCM 30-pin harness connector terminal "2A" (Blue/Yellow wire). If PCM detected APP sensor No. 2 voltage reading is 4.5 volts, PCM determines APP sensor No. 2 circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Connector or terminal malfunction
2. Open circuit in Blue/Yellow wire between APP sensor 6-pin harness connector terminal "C" and PCM 30-pin harness connector terminal "2A"
3. Open circuit in Brown wire between APP sensor 6-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "2H"
4. Short circuit to constant voltage supply circuit in Blue/Yellow wire between APP sensor 6-pin harness connector terminal "C" and PCM 30-pin harness connector terminal "2A"
5. TP sensor malfunction

PCM compares Throttle Position (TP) sensor No. 1 signal value and TP sensor No. 2 signal value and if signal correlation is out of specification, PCM determines TP sensor has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. PCM malfunction
2. TP sensor malfunction

PCM compare Accelerator Pedal Position (APP) sensor No. 1 signal value and APP sensor No. 2 signal value and if signal correlation is out of specification, PCM determines APP sensors have malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. APP sensor malfunction
2. PCM malfunction

PCM monitors input voltage from BARO sensor. If input voltage at PCM 30-pin harness connector terminal "1G" is less than 1.99 volts, PCM determines BARO sensor circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

1. BARO sensor malfunction
2. Connector or terminal malfunction
3. Open circuit in Red/Black wire between BARO sensor 3-pin harness connector terminal "C" and PCM 30-pin harness connector terminal "2K"
4. PCM malfunction
5. Short circuit to ground in Pink wire between BARO sensor 3-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "1G"

PCM monitors input voltage from BARO sensor. If input voltage at PCM 30-pin harness connector terminal "1G" is more than 4.43 volts, PCM determines BARO sensor circuit has malfunction. This is a Continuous Monitor (CM). MIL illuminates if PCM detects malfunction condition during first drive cycle. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

1. BARO sensor malfunction
2. Connector or terminal malfunction
3. Open circuit in Brown wire between BARO sensor 3-pin harness connector terminal "B" and PCM 30-pin harness connector terminal "2H"
4. Open circuit in Pink wire between BARO sensor 3-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "1G"
5. PCM malfunction
6. Short circuit to power in Pink wire between BARO sensor 3-pin harness connector terminal "A" and PCM 30-pin harness connector terminal "1G"

The PCM monitors pump load current (EVAP line pressure), while evaporative leak monitor is operating. If pump load current is lower than specified, PCM determines EVAP system leak detection pump motor circuit has a malfunction. This is a intermittent monitor (other). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Open circuit in White wire between main relay harness connector terminal "E" and EVAP system leak detection pump 4-pin harness connector terminal "A"
2. Open circuit in Pink wire between EVAP system leak detection pump 4-pin harness connector terminal "D" and PCM 27-pin harness connector terminal "3Y"
3. PCM malfunction
4. Poor connection at EVAP system leak detection pump 4-pin harness connector or PCM 27-pin harness connector
5. Short to ground circuit in Pink wire between EVAP system leak detection pump 4-pin harness connector terminal "D" and PCM 27-pin harness connector terminal "3Y"

Scheme 46

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Verify Related Pending Code Or Stored DTCs - Turn ignition off, then on (engine off). Verify related PENDING CODE or stored DTCs. If no other DTCs are present, go to next step. If DTC P2405 is present, go to «DTC P2405: EVAPORATIVE EMISSION SYSTEM LEAK DETECTION PUMP SENSE CIRCUIT - LOW INPUT»(ref-151885-S23550087082003082600000).
4. Inspect EVAP System Leak Detection Pump Connector For Poor Connection - Turn ignition off. Disconnect EVAP system leak detection pump 4-pin harness connector. Inspect for poor connection (such as damaged, pulled-out pins, corrosion). If malfunctions are not present, go to next step. If any malfunctions are present, repair or replace terminal. After repair, go to step 10.
5. Inspect EVAP System Leak Detection Pump Motor Circuit For Open Circuit - Disconnect main relay. Check for continuity in White wire between EVAP system leak detection pump 4-pin harness connector terminal "A" and main relay harness connector terminal "E". (Scheme 48) If continuity is present, go to next step. If continuity is not present, repair open circuit in White wire between EVAP system leak detection pump 4-pin harness connector terminal "A" and main relay harness connector terminal "E" or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 10.
6. Inspect PCM Connector For Poor Connection - Inspect for poor connection (such as damaged, pulled-out terminals, corrosion). If malfunction is not present, go to next step. If any malfunction is present, repair or replace suspected terminal. After repair, go to step 10.
7. Inspect EVAP System Leak Detection Pump Motor Circuit For Short To Ground - Check for continuity between EVAP system leak detection pump 4-pin harness connector terminal "D" (Pink wire) and body ground. If continuity is not present, go to next step. If continuity is present, repair short circuit to ground in Pink wire between EVAP system leak detection pump 4-pin harness connector terminal "D" and PCM 27-pin harness connector terminal "3Y". After repair, go to step 10.
8. Inspect EVAP System Leak Detection Pump Motor Circuit For Open Circuit - Check for continuity in Pink wire between EVAP system leak detection pump 4-pin harness connector terminal "D" and PCM 27-pin harness connector terminal "3Y". (Scheme 48) If continuity is present, go to next step. If continuity is not present, repair open circuit in Pink wire between EVAP system leak detection pump 4-pin harness connector terminal "D" and PCM 27-pin harness connector terminal "3Y" or replace wire harness. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to step 10.
9. Inspect EVAP System Leak Detection Pump - Perform EVAP System Leak Detection Pump Inspection. Refer to «FUEL EVAPORATIVE SYSTEM - EXCEPT PROTEGE & PROTEGE5»(ref-151892-S26634580692003010900000) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If EVAP system leak detection pump is okay, go to next step. If EVAP system leak detection pump is faulty, replace EVAP system leak detection pump. After repair, go to next step.
10. Verify Trouble Shooting Of DTC P2401 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and perform «MODE 4 - EVAP SYSTEM REPAIR VERIFICATION DRIVE MODE»(ref-151885-S17467843762003010900000) under DRIVE CYCLES. If PENDING CODE of same DTC is not present, go to next step. If PENDING CODE of same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
11. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM monitors pump load current (EVAP line pressure), while evaporative leak monitor is operating. If pump load current is more than specified, PCM determines EVAP system leak detection pump motor circuit has a malfunction. This is a intermittent monitor (other). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Damaged PCM
2. Short to power circuit in Pink wire between EVAP system leak detection pump 4-pin harness connector terminal "D" and PCM 27-pin harness connector terminal "3Y"

PCM monitors pump load current (EVAP line pressure), while evaporative leak monitor is operating. After obtaining reference current value, if the time in which pump load current reaches reference current value is less than specification, PCM determines air filter has a malfunction. This is a intermittent monitor (other). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for same malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. Air filter clogging
2. Damaged PCM
3. EVAP hose bending

PCM monitors pump load current (EVAP line pressure), while evaporative leak monitor is operating. If the current is less than specification while PCM obtains reference current value, PCM determines EVAP system leak detection pump orifice has a malfunction. This is a intermittent monitor (other). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. EVAP system leak detection pump orifice fallen off
2. EVAP system leak detection pump motor malfunction
3. PCM malfunction

PCM monitors pump load current (EVAP line pressure), while evaporative leak monitor is operating. If current is more than specification while PCM obtains reference current value, PCM determines EVAP system leak detection pump orifice has a malfunction. This is a intermittent monitor (other). MIL illuminates if PCM detects malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for malfunction has been stored in PCM. PENDING CODE is available if PCM detects malfunction condition during first drive cycle. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. EVAP system leak detection pump orifice clogging
2. EVAP system leak detection pump motor malfunction
3. PCM malfunction

PCM monitors pump load current (EVAP line pressure), while evaporative leak monitor is operating. When either of following is detected 28 times or more successively, PCM determines EVAP system leak detection pump heater has a malfunction

1. While obtaining reference current value, change in pump load current exceeds specification
2. After obtaining reference current value, pump load current is kept lower than maximum pump load current for more than specified time

This is a intermittent monitor (other). MIL illuminates if PCM detects malfunction condition. PENDING CODE is available if PCM detects malfunction condition. FREEZE FRAME DATA is available. DTC is stored in PCM memory.

Possible causes are

1. EVAP system leak detection pump heater malfunction
2. PCM malfunction

PCM judges generator output voltage is more than 17 volts or battery voltage is less than 11 volts during engine running.

Possible causes are

1. Battery malfunction
2. Generator malfunction
3. Open circuit between generator terminal "B" and positive battery terminal
4. PCM, generator and/or battery are poorly connected
5. PCM is poorly connected

Scheme 47

1. If FREEZE FRAME DATA has been recorded, go to next step. If FREEZE FRAME DATA has not been recorded, record FREEZE FRAME DATA. Go to next step.
2. Verify Related Repair Information Availability - Check for related Service Bulletins and/or on-line repair information availability. If any related repair information is available, perform repair or diagnosis according to available repair information. If vehicle is not repaired, go to next step. If related repair information is not available, go to next step.
3. Inspect Battery - Turn ignition off. Inspect battery. If battery is okay, go to next step. If battery is faulty, replace battery. After repair, go to step 7.
4. Inspect Poor Installation Of Generator Terminal - Turn ignition off. Check for looseness of generator terminal "B" installation nut. see scheme 37 If installation nut is not loose, go to next step. If installation nut is loose, tighten generator terminal "B" installation nut. After repair, go to step 7.
5. Inspect Poor Installation Of Positive Battery Terminal - Check for looseness of positive battery terminal. If positive battery terminal is not loose, go to next step. If terminal is loose, connect positive battery terminal correctly. After repair, go to step 7.
6. Inspect Battery Charging Circuit - Start engine. Disconnect positive battery terminal. If engine does not stall, go to next step. If engine stalls, repair or replace wire harness between generator terminal "B" (Black/White wires) and positive battery terminal (Black/Red wire). See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, go to next step.
7. Verify Trouble Shooting Of DTC P2502 Is Completed - Make sure to reconnect all disconnected connectors. Clear DTC from PCM memory using WDS or equivalent. Turn ignition off. Start engine and warm up completely. If same DTC is not present, go to next step. If same DTC is present, replace PCM. For PCM removal and installation, see «POWERTRAIN CONTROL MODULE»(ref-151901-S39392855062003010900000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. After repair, go to next step.
8. Verify After Repair Procedure - Using scan tool, perform After Repair Procedure. See «AFTER REPAIR PROCEDURE»(ref-151885-S09015238672003090200000). If any DTCs are present, go to appropriate DTC inspection. Refer to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-151885-S34958757572003010900000). If no DTCs are present, trouble shooting is complete.

PCM needs more than 20 amps from generator, and judges generator output voltage to be less than 8.5 volts during engine running.

Possible causes are

1. Drive belt misadjustment
2. Generator malfunction
3. Open and/or short circuit to GND in Yellow/Red wire between generator 2-pin harness connector terminal "P" and PCM 30-pin harness connector terminal "1AA"
4. Open and/or short circuit to GND in Green wire between generator 2-pin harness connector terminal "D" and PCM 30-pin harness connector terminal "1AD"
5. PCM and/or generator are poorly connected

PCM judges generator output voltage is more than 18.5 volts or battery voltage is more than 16.0 volts during engine running.

Possible causes are

1. Generator malfunction
2. PCM and/or generator are poorly connected
3. Short circuit to power in Green wire between generator 2-pin harness connector terminal "D" and PCM 30-pin harness connector terminal "1AD"

1. CAN system related harness malfunction
2. Related module communication error

Possible causes are

1. ABS/TCS HU/CM malfunction
2. Instrument cluster malfunction
3. Malfunction of connectors between PCM, TCM, ABS/TCS HU/CM and instrument cluster
4. Open or short circuit in wiring harness
5. PCM malfunction
6. TCM malfunction

Scheme 48

1. Determining Location Of A Malfunction - Determine malfunctioning part of CAN system. See «PROCEDURES FOR DETERMINING LOCATION OF A MALFUNCTION»(ref-151885-S41755846032003100900000) under SYSTEM TESTS. see scheme 38 If malfunction is not part of wire harness "E" or instrument cluster, go to next step. If malfunction is part of wire harness "E" or instrument cluster, go to step 6.
2. Determining Location Of A Malfunction - If malfunction is not part of wire harness "D" or ABS/TCS HU/CM, go to next step. If malfunction is part of wire harness "D" or ABS/TCS HU/CM, go to step 12.
3. Determining Location Of A Malfunction - If malfunction is not part of wire harness "C", go to next step. If malfunction is part of wire harness "C", go to step 14.
4. Determining Location Of A Malfunction - If malfunction is not part of wire harness "B" or TCM, go to next step. If malfunction is part of wire harness "B" or TCM, go to step 17
5. Determining Location Of A Malfunction - If malfunction is not part of wire harness "A" or PCM, trouble shooting is completed. If malfunction is part of wire harness "A" or PCM, go to step 19.
6. Inspect Instrument Cluster Connector - Disconnect negative battery cable Disconnect instrument cluster harness connector If instrument cluster harness connector is okay, go to next step. If instrument cluster harness connector is faulty, replace wire harness.
7. If vehicle is equipped with ABS/TCS, go to next step. If vehicle is not equipped with ABS/TCS, go to step 9.
8. Inspect Wire Harness Between ABS/TCS HU/CM & Instrument Cluster - Disconnect ABS/TCS HU/CM harness connector. Inspect following wire harness between ABS/TCS HU/CM and instrument cluster harness connector terminals for short to ground, short to power supply, and open circuit: "R" - "2W" (CAN_L) "O" - "2X" (CAN_H) If wire harness is okay, replace instrument cluster. After repair, go to step 21. If wire harness is faulty, replace wire harness.
9. If inspected vehicle has a automatic transaxle, go to next step. If inspected vehicle has a manual transaxle, go to step 11.
10. Inspect wire Harness Between TCM & Instrument Cluster - Disconnect TCM harness connector. Inspect following wire harness between TCM and instrument cluster harness connector terminals for short to ground, short to power supply, and open circuit: FN4A-EL "2X" - "2W" (CAN_L) "2W" - "2X" (CAN_H) If wire harness is okay, replace instrument cluster. After repair, go to step 21. If wire harness is faulty, replace wire harness.
11. Inspect wire Harness Between PCM & Instrument Cluster - Disconnect PCM harness connector. Inspect following wire harness between PCM and instrument cluster harness connector terminals for short to ground, short to power supply, and open circuit: "2R" - "2W" (CAN_L) "2U" - "2X" (CAN_H) If wire harness is okay, replace instrument cluster. After repair, go to step 21. If wire harness is faulty, replace wire harness.
12. Inspect ABS/TCS HU/CM Connector - Disconnect negative battery cable. Disconnect ABS/TCS HU/CM harness connector. If ABS/TCS HU/CM harness connector is okay, go to next step. If ABS/TCS HU/CM harness connector is faulty, replace wire harness.
13. Inspect Wire Harness Between ABS/TCS HU/CM & Instrument Cluster - Disconnect instrument cluster harness connector. Inspect following wire harness between ABS/TCS HU/CM and instrument cluster harness connector terminals for short to ground, short to power supply, and open circuit: "R" - "2W" (CAN_L) "O" - "2X" (CAN_H) If wire harness is okay, replace ABS/TCS HU/CM. After repair, go to step 21. If wire harness is faulty, replace wire harness.
14. If inspected vehicle has a automatic transaxle, go to next step. If inspected vehicle has a manual transaxle, go to step 16.
15. Inspect Wire Harness Between TCM & ABS/TCS HU/CM - Disconnect negative battery cable. Disconnect TCM harness connector. Disconnect ABS/TCS HU/CM harness connector. Inspect following wire harness between TCM and ABS/TCS HU/CM harness connector terminals for short to ground, short to power supply, and open circuit: FN4A-EL "2X" - "K" (CAN_L) "2W" - "O" (CAN_H) If wire harness is okay, go to step 21. If wire harness is faulty, replace wire harness.
16. Inspect Wire Harness Between PCM & ABS/TCS HU/CM - Disconnect negative battery cable. Disconnect PCM connector. Disconnect ABS/TCS HU/CM harness connector. Inspect following wire harness between PCM and ABS/TCS HU/CM harness connector terminals for short to ground, short to power supply, and open circuit: "2R" - "K" (CAN_L) "2U" - "O" (CAN_H) If wire harness is okay, go to step 21. If wire harness is faulty, replace wire harness.
17. Inspect TCM Connector - Disconnect negative battery cable Disconnect TCM harness connector If TCM harness connector is okay, go to next step. If TCM harness connector is faulty, replace wire harness.
18. Inspect Wire Harness Between TCM & Instrument Cluster - Disconnect instrument cluster harness connector. Inspect following wire harness between TCM and instrument cluster harness connector terminals for short to ground, short to power supply, and open circuit: FN4A-EL "2X" - "2W" (CAN_L) "2W" - "2X" (CAN_H) If wire harness is okay, replace TCM. After repair, go to step 21. If wire harness is faulty, replace wire harness.
19. Inspect PCM Connector - Disconnect negative battery cable. Disconnect PCM harness connector. If PCM harness connector is okay, go to next step. If PCM harness connector is faulty, replace wire harness.
20. Inspect Wire Harness Between PCM & Instrument Cluster - Disconnect instrument cluster harness connector. Inspect following wire harness between PCM and instrument cluster harness connector terminals for short to ground, short to power supply, and open circuit: "2R" - "2W" (CAN_L) "2U" - "2X" (CAN_H) If wire harness is okay, replace PCM. After repair, go to next step. If wire harness is faulty, replace wire harness.
21. Check DTC Indicated - Connect PCM connector Connect TCM connector Connect ABS/TCS HU/CM connector Connect instrument cluster connector Clear DTC from module memory using scan tool Perform KOEO/KOER self-test If DTCs U0073, U1900 and/or U2516 are indicated, repeat step 1. If DTCs U0073, U1900 and/or U2516 are not indicated, trouble shooting is completed.

Incorrect constant voltage.

Possibly caused by a constant voltage circuit malfunction. (Barometric Pressure (BARO) sensor uses constant voltage.

TCM

1. Check display of DTC U0100, using scan tool. (Scheme 49)
2. Referring to TCM Malfunction Locator Table, determine malfunctioning part of CAN system. see scheme 38and (Scheme 51).

Scheme 49

ABS/TCS HU/CM

1. Access and monitor "PCM_MSG" and "TCM_MSG" of PID using scan tool.
2. Referring to PID/DATA MONITOR, confirm display status of the PID. (Scheme 49)
3. Referring to ABS/TCS HU/CM Malfunction Locator Table, determine malfunctioning part of CAN system. see scheme 38and see scheme 42.

Scheme 50

Instrument Cluster

1. Access and monitor "PCM_MSG", "TCM_MSG" and "ABS_MSG" of PID using the SST (WDS or equivalent).
2. Referring to PID/DATA MONITOR, confirm display status of PID. (Scheme 49)
3. Referring to Instrument Cluster Malfunction Locator table, determine malfunctioning part of CAN system. see scheme 38and see scheme 43.

Scheme 51

When Idling Cannot Be Continued

1. Remove Oil Control Valve (OCV) and verify spool valve is at maximum retard position.
2. Connect OCV.
3. Turn ignition on.
4. Verify spool valve is at maximum retard position. If spool valve is stuck in advance direction, inspect for short circuit in harnesses or connectors between OCV and PCM.
5. Inspect variable timing actuator.

When Idling Can Be Continued

1. Disconnect oil control valve (OCV) connector.
2. Warm up engine and let idle.
3. Apply battery voltage to OCV and verify engine idles roughly or stalls. If engine idles roughly or stalls, inspect timing belt component (valve timing deviation). If engine does not idle roughly or stalls, go to next step.
4. Remove OCV and perform spool valve operation inspection. «OIL CONTROL VALVE - MAZDA6 & MIATA ONLY»(ref-151892-S39070078312003010900000) under VARIABLE VALVE TIMING CONTROL in SYSTEM & COMPONENT TESTING - MAZDA6, MIATA, MPV, PROTEGE & PROTEGE5 article. If not as specified, inspect following: OCV Harnesses and connectors between OCV and PCM for open or short circuit If as specified, inspect following hydraulic passages for clogging or leakage or both Oil pressure switch to OCV OCV to camshaft Camshaft internal passage
5. If all passages are okay, replace camshaft pulley (with built-in variable valve timing actuator).

AFTER REPAIR PROCEDURE

Connect scan tool. Turn ignition off, then on (engine off). Record DTCs if present. Erase all diagnostic data with scan tool.