Engine Controls - Self-Diagnostics: Other Mazda MPV II

Pending Codes

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).

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 the freeze frame data will not be overwritten again.

Apply parking brake. Place shift lever in Park (A/T) or Neutral (M/T). Block wheels. Turn off all electrical accessories. Ensure engine is at normal operating temperature.

Perform visual inspection. Ensure air cleaner and inlet ducts are clean, and system wiring harness is properly connected. Check for bent or broken connector terminals and corroded or loose wires. Check Powertrain Control Module (PCM), sensors and actuators for physical damage. Check engine coolant for proper level and mixture. Check for proper transmission fluid level and quality.

Turn ignition off. Ensure proper memory (EPROM) card is inserted into NGS scan tool. Connect service connections of adapter cable to vehicle Data Link Connector (DLC) and the NGS scan tool. see scheme 1and see scheme 2. Connect NGS scan tool power supply cable to power and listen for a double beep to indicate that scan tool is on.

To access freeze frame data, program scan tool using the following steps

1. Select GENERIC OBD II FUNCTIONS.
2. Select CONT.
3. Select FREEZE FRAME PID DATA.
4. Select START and follow scan tool prompts.

If system did not store any DTCs, scan tool will display NO TRIGGER CODE SET.

Mode 1 (PCM Adaptive Memory Drive Mode)

1. Using scan tool, check RFCFLAG PID status. If RFCFLAG PID is on, procedure is complete, PCM has adaptive memory. If RFCFLAG PID is off, perform following procedure before performing EGR monitor repair verification drive mode or HO2S/TWC monitor repair verification drive mode.
2. Start engine and warm to normal operating temperature. Ensure all electrical and A/C loads are off. Ensure ignition timing and idle speed are within specification. Adjust as necessary. See BASIC DIAGNOSTIC PROCEDURES article. Ensure nothing is connected to DLC. Increase engine RPM to specified speed. (Scheme 82)
3. Operate engine at specified RPM for minimum of 15 seconds. Idle engine for more than 20 seconds when cooling fan stops. Using scan tool, monitor RPM PID, FAN2 PID (with A/C) or FAN1 PID (without A/C). Turn ignition off and on. Using scan tool, check RFCFLAG PID to confirm PCM adaptive memory status. If RFCFLAG PID is on, procedure is complete, PCM has adaptive memory. If RFCFLAG PID is off, go back to previous step.

Scheme 82

Mode 2 (EGR Monitor Repair Verification Drive Mode)

1. Using scan tool, check RFCFLAG PID status. If RFCFLAG PID is off, perform PCM adaptive memory drive mode first and go to next step. If RFCFLAG PID is on, go to next step.
2. Start engine and warm to normal operating temperature. Ensure all electrical and A/C loads are off.
3. Drive vehicle at specified speeds. (Scheme 83) Stop vehicle and access ON BOARD SYSTEM READINESS menu of GENERIC OBD II FUNCTIONS to check drive mode completion status. RFC should change from NO to YES when test is complete. If test is not complete, turn ignition off and repeat this step. If test is complete, go to next step.
4. Check test results in DIAGNOSTIC MONITORING TEST RESULTS menu of GENERIC OBD II FUNCTIONS. If results are okay (MEAS are within specification), ensure no DTCs are present. If no DTCs are present, repairs are complete. If results are not okay (MEAS are not within specification), repairs are not complete.

Scheme 83

Mode 3 (HO2S/TWC Monitor Repair Verification Drive Mode)

1. Using scan tool, check RFCFLAG PID status. If RFCFLAG PID is off, perform PCM adaptive memory drive mode first and go to next step. If RFCFLAG PID is on, go to next step.
2. Start engine and warm to normal operating temperature. Ensure all electrical and A/C loads are off.
3. Drive vehicle at specified speeds. (Scheme 84) Stop vehicle and access ON BOARD SYSTEM READINESS menu of GENERIC OBD II FUNCTIONS to check drive mode completion status. RFC should change from NO to YES when test is complete. If test is not complete, turn ignition off and repeat this step. If test is complete, go to next step.
4. Check test results in DIAGNOSTIC MONITORING TEST RESULTS menu of GENERIC OBD II FUNCTIONS. If results are okay (MEAS are within specification), ensure no DTCs are present. If no DTCs are present, repairs are complete. If results are not okay (MEAS are not within specification), repairs are not complete.

Scheme 84

Mode 4 (EVAP Monitor Repair Verification Drive Mode)

Note. If EVAP monitor repair verification drive mode cannot be performed because vehicle cannot be driven under conditions specified for this test, perform evaporative system test procedure as an alternative. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article.

1. Ensure following conditions are met: Engine coolant temperature is 32-95°F (0-35°C). Intake air temperature is 50-140°F (10-60°C). Barometric pressure is 72.3 kPa. Fuel Tank Level (FTL) PID V is.5-2.5 volts. Ensure all electrical and A/C loads are off.
2. Start and operate engine at 3500 RPM to warm to normal operating temperature. Operate vehicle as specified. (Scheme 85) Stop vehicle and access ON BOARD SYSTEM READINESS menu of GENERIC OBD II FUNCTIONS to check drive mode completion status. RFC should change from NO to YES when test is complete. If test is not complete, turn ignition off and repeat this step. If test is complete, go to next step.
3. Check test results in DIAGNOSTIC MONITORING TEST RESULTS menu of GENERIC OBD II FUNCTIONS. If results are okay (MEAS value of 10:21:00 and 10:22:00 are within specification), ensure DTCs are not present. If DTCs are not present, repairs are complete. If results are not okay (MEAS value of 10:21:00 and 10:22:00 are not within specification), repairs are not complete.

Scheme 85

SUMMARY

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

Condition

PCM monitors control signal at terminal No. 93. If PCM turns off HO2S heater (does not ground circuit) and voltage remains low, DTC is set. Causes may include the following

1. Faulty right front HO2S.
2. Open in Black/White wire between main relay harness connector terminal "D" and right front HO2S harness connector terminal "C".
3. Open or short to ground in Yellow wire between right front HO2S harness connector terminal "D" and PCM harness connector terminal No. 93.
4. Poor connection(s) at HO2S harness connector or PCM harness connector terminal.
5. PCM malfunction.

Right front HO2S heater is controlled by a duty signal.

PCM monitors control signal at terminal No. 93. If PCM turns on HO2S heater (grounds circuit) and voltage remains high, DTC is set. Causes may include the following

1. Faulty Right/Front HO2S.
2. Short to power in Yellow wire between right front HO2S harness connector terminal "D" and PCM harness connector terminal No. 93.
3. Short at right front HO2S harness connector or PCM harness connector terminal.
4. PCM malfunction.

Right front HO2S heater is controlled by a duty signal.

PCM monitors control signal at terminal No. 95. If PCM turns off HO2S heater (does not ground circuit) and voltage remains low, DTC is set. Causes may include the following

1. Faulty right rear HO2S.
2. Open in Black/White wire between main relay harness connector terminal "D" and HO2S harness connector terminal "C".
3. Open or short to ground in Light Green/Black wire between HO2S harness connector terminal "D" and PCM harness connector terminal No. 95. see scheme 8
4. Poor connection(s) at right rear HO2S harness connector or PCM harness connector.
5. PCM malfunction.

PCM monitors control signal at terminal No. 95. If PCM turns on right rear HO2S heater (grounds circuit) and voltage remains high, DTC is set. Causes may include the following

1. Faulty right rear HO2S.
2. Short to power in Black/White wire between right rear HO2S harness connector terminal "D" and PCM terminal No. 95.
3. Shorted right rear HO2S or PCM terminal.
4. PCM malfunction.

PCM monitors control signal at terminal No. 94. If PCM turns off left front HO2S heater (does not ground circuit) and voltage remains low, DTC is set. Causes may include the following

1. Faulty left front HO2S.
2. Open or short to ground in White wire between left front HO2S harness connector terminal "B" and PCM harness connector terminal No. 94.
3. Open in Black/White wire between main relay harness connector terminal "D" and left front HO2S harness connector terminal No. 94.
4. PCM malfunction.

Left front HO2S heater is controlled by a duty signal.

PCM monitors control signal at terminal No. 94. If PCM turns on left front HO2S heater (grounds circuit) and voltage remains high, DTC is set. Causes may include the following

1. Faulty left front HO2S.
2. Short to power in orange wire between left front HO2S harness connector terminal "B" and PCM harness connector terminal No. 94.
3. Poor connection at left front HO2S harness connector or PCM harness connector terminal.
4. PCM malfunction.

Left front HO2S heater is controlled by a duty signal.

PCM monitors control signal at terminal No. 96. If PCM turns off left rear HO2S heater (does not ground circuit) and voltage remains low, DTC is set. Causes may include the following

1. Faulty left rear HO2S.
2. Open in Black/White wire between left rear HO2S harness connector terminal "A" and main relay harness connector terminal "D".
3. Open or short to ground in Green/Orange wire between left rear HO2S harness connector terminal "B" and PCM harness connector terminal No. 96.
4. Poor connection(s) at left rear HO2S or PCM connector.
5. PCM malfunction.

PCM monitors control signal at terminal No. 96. If PCM turns on left rear HO2S heater (grounds circuit) and voltage remains high, DTC is set. Causes may include the following

1. Faulty left rear HO2S.
2. Short to power in Green/Orange wire between left rear HO2S harness connector and PCM harness connector.
3. Shorted connection(s) at left rear HO2S or PCM terminal.
4. PCM malfunction.

PCM monitors input signal of MAF sensor at terminal No. 88. If PCM input voltage is less than .24 volt, DTC is set. Causes may include the following

1. Faulty MAF sensor.
2. Open or short to ground in Blue/White wire between MAF/IAT sensor harness connector terminal "E" and PCM harness connector terminal No. 88.
3. Open in wire between main relay harness connector (Yellow wire) and MAF/IAT sensor harness connector terminal "B" (White/Red wire).
4. Poor connection at MAF/IAT sensor connector or PCM connector.
5. PCM malfunction.

PCM monitors input signal of MAF sensor at terminal No. 88 when ignition is turned on. If PCM input voltage is more than 4.8 volts, DTC is set. Causes may include the following

1. Faulty MAF/IAT sensor.
2. Open or short to power in Green/Yellow wire between MAF/IAT sensor harness connector terminal "D" and PCM harness connector terminal No. 36.
3. Poor connection at MAF/IAT sensor connector or PCM connector terminal No. 88.
4. PCM malfunction.

PCM monitors differences between intake manifold vacuum and atmospheric pressure at idle. The signal is from EGR boost sensor and is switched by EGR boost sensor solenoid. If difference is less than 1.9 in. Hg, DTC is set. Causes may include the following

1. Faulty EGR boost sensor.
2. Faulty EGR boost sensor solenoid.
3. Vacuum line fault.
4. PCM malfunction.

PCM monitors input voltage during monitoring conditions. If voltage at terminal No. 34 is less than .2 volt, DTC is set. Causes may include the following

1. Faulty EGR boost sensor.
2. Short to ground in Violet/Red wire between EGR boost sensor harness connector terminal "B" and PCM harness connector terminal No. 34.
3. Open in Pink/Blue wire between EGR boost sensor harness connector terminal "C" and PCM harness connector terminal No. 90
4. Faulty connection at EGR boost sensor connector or PCM connector.
5. PCM malfunction.

PCM monitors input voltage during monitoring conditions. If voltage at PCM terminal No. 34 is more than 4.8 volts, DTC is set. Causes may include the following

1. Faulty EGR boost sensor.
2. Open in Brown/Yellow wire between EGR boost sensor harness connector terminal "A" and PCM harness connector terminal No. 91
3. Open in Violet/Red wire between EGR boost sensor harness connector terminal "B" and PCM harness connector terminal No. 34
4. Faulty connector at EGR boost sensor harness connector or PCM harness connector.
5. PCM malfunction.

If IAT temperature exceeds ECT temperature by 104°F or more with ignition on, DTC is set. Causes may include the following

1. Faulty IAT sensor.
2. Faulty connector MAF/IAT sensor or PCM.
3. PCM malfunction.

PCM monitors input voltage at PCM terminal No. 39. If voltage is less than .2 volt, DTC is set. Causes may include the following

1. Faulty IAT sensor.
2. Short circuit in Violet wire between MAF/IAT sensor harness connector terminal "F" and PCM harness connector terminal No. 39.
3. Short in harness between IAT signal (Violet wire) and IAT ground (Brown/Yellow wire).
4. PCM malfunction.

PCM monitors input voltage at terminal No. 39 If voltage is more than 4.8 volts, DTC is set. Causes may include the following

1. Faulty IAT sensor.
2. Open or short to power in Violet wire between MAF/IAT sensor harness connector terminal "F" and PCM harness connector terminal No. 39.
3. Open in Brown/Yellow wire between MAF/IAT sensor harness connector terminal "A" and PCM harness connector terminal No. 91.
4. Faulty connector at MAF/IAT sensor or PCM
5. PCM malfunction.

After vehicle has been cold soaked (turned off) for 6 hours, PCM monitors ECT sensor maximum and minimum value when engine is started and 5 minutes after starting engine. If ECT sensor maximum and minimum values vary less than 10°F, DTC is set. Causes may include the following

1. Faulty ECT sensor.
2. Faulty connector at ECT sensor or PCM.
3. PCM malfunction.

PCM monitors input voltage at terminal No. 38 If voltage is less than .14 volt, DTC is set. Causes may include the following

1. Faulty ECT sensor.
2. Short in Red/Blue wire between ECT sensor harness connector terminal No. 1 and PCM harness connector terminal No. 38.
3. Short in harness between ECT signal (Red/Blue wire) and ECT ground (Brown/Green wire).
4. PCM malfunction.

PCM monitors input voltage at terminal No. 38 If voltage is more than 4.6 volts, DTC is set. Causes may include the following

1. Faulty ECT sensor.
2. Open or short to power in Red/Blue wire between ECT sensor harness connector terminal No. 1 and PCM harness connector terminal No. 38.
3. Open in Brown/Yellow wire between ECT sensor harness connector terminal No. 2 and PCM harness connector terminal No. 91.
4. Faulty connector at ECT sensor or PCM.
5. PCM malfunction.

When engine is running, PCM monitors input voltage at terminal No. 89. If voltage is less than .16 volt, DTC is set. Causes may include the following

1. Faulty TP sensor.
2. Open or short between TP sensor harness connector terminal No. 2 (White wire) and PCM harness connector terminal No. 89 (Brown/yellow wire)
3. Faulty connector at TP sensor or PCM.
4. PCM malfunction.

When engine is running, PCM monitors input voltage at terminal No. 89. If voltage is more than 4.9 volts, DTC is set. Causes may include the following

1. Faulty TP sensor.
2. Open in Brown wire between TP sensor harness connector terminal No. 3 and PCM harness connector terminal No. 91.
3. Short to power between TP sensor harness connector terminal No. 2 (White wire) and PCM harness connector terminal No. 89 (Brown/Yellow wire).
4. Faulty connector or terminal at TP sensor or PCM.
5. PCM malfunction.

PCM monitors input voltage from ECT at terminal No. 38. When cold engine is started, PCM checks length of time for engine to reach expected temperature. If temperature is not reached within specified time, DTC is set. Causes may include the following

1. Faulty ECT sensor.
2. Faulty connection or connector.
3. PCM malfunction.

PCM monitors ECT and compares actual reading to expected ECT reading. If difference is more than specified, DTC is set. Causes may include the following

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

PCM monitors front HO2S's during Drive Mode 3. If front HO2S signal fluctuates outside limits, DTC is set. Possible causes are

1. Front HO2S malfunction.
2. Exhaust system leak.
3. Low engine compression or engine malfunction.
4. Oxygen sensor harness and/or connector.
5. Fuel injection system malfunction.
6. Intake system malfunction.

DTC is set when front HO2S signal voltage does not exceed .55 volt for 94 seconds after engine has reached normal operating temperature (coolant temperature more than 158°) and engine speed is more than 1500 RPM. Possible causes are

1. Front HO2S malfunction.
2. Front HO2S heater malfunction.
3. Exhaust system leak.
4. Open or short circuit between front HO2S harness connector(s) and PCM harness connector.
5. Engine compression low.
6. Engine malfunction.

DTC is set when rear HO2S signal voltage is more than .45 volt for 6 seconds during deceleration fuel cut. Possible causes are

1. Rear HO2S malfunction.
2. Short to power in wiring between rear HO2S harness connector(s) and PCM harness connector.

DTC is set when rear HO2S signal voltage does not exceed .55 volt for 30 seconds after engine has reached normal operating temperature and engine speed is more than 1500 RPM. Voltage is monitored by PCM during Drive Mode 3. Possible causes are

1. Faulty rear HO2S.
2. Open or short between rear HO2S harness Connector(s) and PCM harness connector.
3. Exhaust Leak.
4. Engine compression (low).
5. Engine Malfunction.

PCM monitors short term fuel trim and long term fuel trim during Drive Mode 1. DTC is set when fuel injection closed loop correction and learning correction are greater than specified value (lean). Deterioration or malfunction of following components and/or systems could contribute to DTC being set. Possible causes are

1. Misfire.
2. Front HO2S malfunction.
3. PRC solenoid malfunction.
4. Fuel system malfunction.
5. Exhaust system leak.
6. Purge solenoid valve malfunction.
7. Intake air system leakage.
8. Low compression.

PCM monitors short term fuel trim and long term fuel trim during Drive Mode 1. DTC is set when fuel injection closed loop correction and learning correction are greater than specified value (rich). Deterioration or malfunction of following components and/or systems could contribute to DTC being set. Possible causes are

1. Misfire.
2. Front HO2S malfunction.
3. PRC solenoid malfunction.
4. Fuel system malfunction.
5. Purge solenoid valve malfunction.
6. PCV system malfunction.

DTC is set when PCM input signal from Crankshaft Position (CKP) sensor signal is irregular. Deterioration or malfunction of following components and/or systems could contribute to DTC P0300 being set. Possible causes are

1. CKP sensor malfunction.
2. CMP sensor malfunction.
3. Ignition coil malfunction.
4. Plug wire malfunction.
5. MAF sensor contamination.
6. Intake air system malfunction.
7. Fuel system malfunction.
8. PRC solenoid malfunction.
9. PCV valve malfunction.
10. EGR system malfunction.
11. Vacuum hoses misrouted or damaged.
12. Wiring or connector malfunction.

DTC is set when PCM input signal from Crankshaft Position (CKP) sensor signal is irregular for a specific cylinder. Deterioration or malfunction of following components and/or systems could contribute to DTC P0301-P0306 being set. Possible causes are

1. Ignition system malfunction on cylinders No. 1-6.
2. Fuel system malfunction.
3. Intake air system malfunction.
4. Vacuum leak.
5. Incorrect CKP sensor air gap.
6. Low compression.
7. Wiring or connector malfunction.

PCM monitors knock sensor signal when load is more than 36 percent, coolant temperature is more than 149°F and engine speed is 1000-4500 RPM. If no knock signal is received after 5 seconds, DTC is set. Causes may include the following

1. Faulty Knock Sensor (KS).
2. Faulty connector or terminals.
3. Open or short between KS harness connector and PCM harness connector.
4. PCM malfunction.

DTC is set when there is no input voltage from Crankshaft Position (CKP) sensor for 4.2 seconds while engine is running. Possible causes are

1. CKP sensor malfunction or dirty.
2. Pulse wheel malfunction.
3. Open or short between CKP sensor harness connector and PCM harness connector.

DTC is set when the difference in manifold pressure is too small between when EGR is open and closed. Possible causes are

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

DTC is set when the difference in manifold pressure is too large between when EGR is open and closed. Possible causes are

1. EGR gasket malfunction.
2. PCM malfunction.

DTC is set when PCM detects rear HO2S value difference becomes closer to value of front HO2S. PCM monitors when vehicle speed is 25-60 MPH, load is 22-45 percent and engine speed is 1000-3000 RPM. Possible causes are

1. Warm Up Three Way Catalytic (WU-TWC) converter deterioration or malfunction.
2. Exhaust system leaks.
3. Loose front or rear HO2Ss.
4. Front HO2S malfunction.

DTC is set when PCM detects excessive difference in fuel tank pressures measured immediately after purge control is stopped with Canister Drain Cut Valve (CDCV) closed and preset period of time has elapsed. Possible causes are

1. Purge solenoid valve malfunction.
2. CDCV malfunction.
3. TPCV malfunction.
4. Vent cut valve malfunction.
5. Charcoal canister malfunction.
6. Catch tank malfunction.
7. Rollover valve malfunction.
8. Cracked fuel tank.
9. Loose fuel tank components (including filler cap).
10. Clogs or leakage in EVAP system hoses.

PCM monitors voltage at terminal No. 18 when ignition is turned on. If voltage is less than 2.7 volts, DTC is set. Possible causes are

1. Purge solenoid valve malfunction.
2. Open or short between purge solenoid valve and PCM harness connectors.
3. Open in wire between purge solenoid valve harness connector terminal "A" and main relay harness connector terminal "D".
4. PCM malfunction.

PCM monitors fuel tank pressure during EVAP leak monitor and when purge solenoid valve is closed. DTC is set when fuel tank pressure difference is too large or small during these conditions. Possible causes are

1. Fuel tank pressure sensor malfunction.
2. Purge solenoid valve malfunction.
3. Open or short in wiring to CDCV.
4. Poor connection at CDCV, fuel tank pressure sensor and/or PCM
5. Charcoal canister clogged.

When engine is running and engine coolant temperature is less than 176°F, PCM monitors input voltage at terminal No. 62. If voltage is less than .2 volt, DTC is set. Causes may include the following

1. Faulty fuel tank pressure (FTP) sensor.
2. Open in Pink/Blue wire between (FTP) sensor harness connector terminal "C" and PCM harness connector terminal No. 90.
3. Short to ground in wiring between FTP sensor harness connector terminal "A" (Red wire) and PCM harness connector terminal No. 62 (Red/Black wire).
4. Faulty connector or terminal.
5. PCM malfunction.

When engine is running and engine coolant temperature is less than 176°F, PCM monitors input voltage at terminal No. 62. If voltage is more than 4.8 volts for 2 seconds, DTC is set. Causes may include the following

1. Faulty FTP sensor.
2. Open between FTP sensor harness connector terminal "A" and PCM harness connector terminal No. 62.
3. Open between FTP sensor harness connector terminal "B" and PCM harness connector terminal No. 91
4. Short in FTP sensor signal circuit to constant voltage supply circuit.
5. Faulty connector.
6. PCM malfunction.

DTC is set when PCM detects excessive difference in fuel tank pressure measured immediately after purge control is stopped with Canister Drain Cut Valve (CDCV) closed. Possible causes are

1. Purge solenoid malfunction.
2. CDCV malfunction.
3. Pressure Control Valve (TPCV) malfunction.
4. Loose or missing fuel filler cap.
5. Charcoal canister malfunction.
6. Catch tank malfunction.
7. Rollover valve malfunction.
8. Cracked fuel tank.
9. Clogs or leakage in system hoses.
10. Fuel level sensor malfunction.
11. Fuel tank pressure sensor malfunction.

DTC is set when PCM detects excessive difference in fuel tank pressures measured immediately after purge control is stopped with Canister Drain Cut Valve (CDCV) closed and preset period of time has elapsed. Possible causes are

1. Purge solenoid valve malfunction.
2. CDCV malfunction.
3. TPCV malfunction.
4. Vent cut valve malfunction.
5. Charcoal canister malfunction.
6. Catch tank malfunction.
7. Rollover valve malfunction.
8. Cracked fuel tank.
9. Loose components.
10. Clogs or leakage in system hoses.

PCM monitors input before and after calculated fuel use of 26 qt. (25 L). If input change is 5 percent less than calculated consumption, DTC is set. Possible cause is fuel gauge sending unit malfunction.

PCM monitors voltage at terminal No. 63. DTC is set when voltage is less than .1 volt for 5 seconds. Possible causes are

1. Fuel gauge sending unit malfunction.
2. Short to ground in Gray/Red wire between fuel gauge sending unit harness connector and PCM harness connector.
3. Connector or terminal damage at fuel gauge sending unit.
4. PCM malfunction.

PCM monitors voltage at terminal No. 63. DTC is set when voltage is more than 4.9 volts for 5 seconds. Possible causes are

1. Fuel gauge sending unit malfunction.
2. Open circuit.
3. Connector or terminal damage.
4. PCM malfunction.

This is a slosh check. PCM monitors input at terminal No. 63 while engine is running. If voltage changes more than 1 volt while vehicle is stopped, DTC is set. Possible cause is fuel gauge sending unit malfunction.

DTC is set when brake pedal is depressed, steering wheel is straight and actual engine speed is 100 RPM lower than expected for 14 seconds. PCM will not set DTC when atmospheric pressure is less than 21.3 in. Hg or intake air temperature is less than 14°F. Possible causes are

1. Idle Air Control (IAC) valve malfunction.
2. Air filter or air intake passage is clogged.
3. A/C relay control circuit malfunction.
4. Generator control circuit malfunction.
5. Purge control solenoid valve malfunction.
6. Low engine compression (excessive blowby).
7. PCM malfunction.

DTC is set when brake pedal is depressed, steering wheel is straight and actual engine speed is 200 RPM higher than expected for 14 seconds. PCM will not set DTC when atmospheric pressure is less than 21.3 in. Hg or intake air temperature is less than 14°F. Possible causes are

1. Idle Air Control (IAC) valve malfunction.
2. Throttle cable misadjusted.
3. Actuator cable misadjusted.
4. Throttle valve malfunction.
5. Vacuum hoses misconnected.
6. PCM malfunction.

DTC is set when PCM receives power steering switch low voltage input at terminal No. 31 for more than 60 seconds while vehicle is operating at more than 37 MPH and ECT is more than 140°F. Possible causes are

1. Power Steering Pressure (PSP) switch malfunction.
2. Short to ground in Black/Blue wire between PSP switch harness connector and PCM harness connector terminal No. 31.
3. PCM malfunction.

DTC is set when PCM has not received brake switch signal while vehicle is operating. Malfunction has to occur 10 consecutive times. Possible causes are

1. Brake switch malfunction.
2. Short in Green/Yellow wire between brake switch harness connector terminal "B" and PCM harness connector terminal No. 92.
3. PCM malfunction.

PCM compares expected and actual MAF input. DTC is set if MAF input is less than 1.09 lbs. min. and throttle opening is 50 percent or more for more than 5 seconds with engine running. Possible causes are

1. MAF sensor malfunction.
2. TP sensor malfunction.
3. Corrosion problems in MAF signal circuit.
4. Voltage drop in MAF signal circuit.

PCM compares expected and actual MAF input. DTC is set if MAF input is more than 13.6 lbs. min. and engine speed is 2000 RPM or less for more than 5 seconds with engine running. Possible causes are

1. MAF sensor malfunction.
2. Corrosion problems in MAF return circuit.
3. Voltage drop in MAF ground circuit.

DTC is set if TP input is less than 12.5 percent when ECT is more than 158°F and MAF input is more than 11.7 lbs. min.. Possible causes are

1. Throttle Position (TP) sensor malfunction.
2. Corrosion on TP signal circuit.
3. Voltage drop on VREF circuit.
4. PCM malfunction.

DTC is set if TP input is more than 50 percent when engine speed is more than 500 RPM and MAF input is less than 8.24 grams/sec. (1.09 lbs./min.) for 5 seconds or more. Possible causes are

1. Throttle Position (TP) sensor malfunction.
2. MAF sensor malfunction.
3. Corrosion in TP sensor signal circuit.
4. Voltage drop in ground circuit.
5. PCM malfunction.

DTC is set when front HO2S signal voltage remains less than .45 volt for 43.2 seconds when engine coolant temperature is more than 158°F and engine speed is more than 1500 RPM. Possible causes are

1. Front HO2S malfunction.
2. Fuel system malfunction.
3. Vacuum leaks.
4. EVAP system malfunction.
5. PCV system malfunction.
6. Low compression.
7. Ignition system malfunction.

Note. Wire color changes at X-03 harness connector between PRC solenoid valve terminal "A" (White/Red wire) and main relay terminal "D" (Yellow wire).

PCM monitors input voltage at terminal No. 44 when ignition is turned on. DTC is set when less than .44 volt is present. Possible causes are

1. PRC solenoid valve malfunction.
2. Open or short in Pink wire between PRC solenoid harness connector terminal "B" and PCM harness connector terminal No. 44.
3. Open in wiring between PRC solenoid valve harness connector terminal "A" and main relay harness connector terminal "D".
4. PCM malfunction.

DTC is set when misfire monitoring circuit sends an extraordinary signal to PCM. Possible cause is: Internal PCM circuit damaged.

PCM monitors CMP sensor input when MAF input is more than .32 lbs. min. DTC is set CKP input is present and CMP input is not present. Possible causes are

1. CMP sensor dirty or malfunctioning.
2. CKP sensor malfunction.
3. Open or short in wiring between CMP sensor harness connector and PCM harness connector.
4. Connector or terminal problem.

Note. Wire color changes at X-03 harness connector between CDCV terminal "A" (White/Red wire) and main relay terminal "D" (Yellow wire).

DTC is set when PCM detects less than 2.7 volts at terminal No. 67 when ignition is turned on. Possible causes are

1. CDCV malfunction.
2. Connector or terminal problem.
3. Open or short in wiring between CDCV harness connector terminal "B" and PCM harness connector terminal No. 67.
4. Open in wiring between CDCV harness connector and main relay harness connector.
5. PCM malfunction.

DTC is set when PCM detects fuel tank pressure is low after engine is started in cold condition and vehicle speed is less than 59 MPH. Possible causes are

1. Canister Drain Cut Valve (CDCV) malfunction.
2. EVAP air filter clogged.
3. Charcoal canister malfunction.
4. EVAP drain passage clogged.
5. FTP sensor malfunction.
6. Purge solenoid valve malfunction.

Note. Wire color changes at X-03 harness connector between EGR boost sensor harness connector terminal "A" (White/Red wire) and main relay harness connector terminal "D" (Yellow wire).

DTC is set when PCM detects less than 2.7 volts at terminal No. 47 when ignition is turned on. Possible causes are

1. EGR boost sensor malfunction.
2. Connector or terminal problem.
3. Open or short in Gray/Black wire between EGR boost sensor harness connector terminal "B" and PCM harness connector terminal No. 47.
4. Open in wiring between EGR boost sensor harness connector terminal "A" and main relay harness connector terminal "D".
5. PCM malfunction.

DTC is set when PCM detects less than 2.7 volts at appropriate terminal when ignition is turned on. Possible causes are

1. EGR valve malfunction.
2. Connector or terminal problem.
3. Open or short in wiring between EGR valve harness connector and PCM harness connector.
4. Open in wiring between EGR valve harness connector terminal "D" and main relay harness connector terminal "D"
5. PCM malfunction.

PCM monitors IAC circuit current when IAC duty is more than 18 percent. DTC is set when current is less than 100 mA or more than 4.5 amps at 77°F for one second. Possible causes are

1. IAC valve circuit malfunction.
2. Connector or terminal problem.
3. Short to power or ground in wiring between IAC harness connector and PCM harness connector.
4. Open in wiring between IAC harness connector and PCM harness connector.
5. PCM malfunction.

PCM monitors intake manifold runner control (IMRC) circuit voltage. DTC is set when PCM terminal No. 3 voltage is 1.6-4.9 volts for 3.2 seconds when IMRC valve is open. Possible causes are

1. Open in IMRC wire harness.
2. Connector or terminal malfunction.
3. IMRC malfunction.
4. PCM malfunction.

PCM monitors intake manifold runner control (IMRC) circuit voltage. DTC is set when PCM terminal No. 3 voltage is less than 1.6 volt for 3.2 seconds when IMRC valve changes from open to closed position. Possible causes are

1. Short to ground in wiring between IMRC harness connector terminal No. 1 (Black/Red wire) and PCM harness connector terminal No. 42 (Black/Yellow wire) or between IMRC harness connector terminal No. 5 (Black/Blue wire) and PCM harness connector terminal No. 3 (Red wire).
2. Connector or terminal malfunction.
3. IMRC malfunction.
4. PCM malfunction.

PCM monitors intake manifold runner control (IMRC) circuit voltage. DTC is set when PCM terminal No. 42 voltage is less than 3 volts when IMRC valve is not operating. Possible causes are

1. Open or short in wiring between IMRC actuator harness connector terminal No. 1 and PCM harness connector terminal No. 42.
2. Open in wiring between main relay terminal "D" and IMRC actuator harness connector terminal No. 2.
3. Connector or terminal malfunction.
4. IMRC malfunction.
5. PCM malfunction.

PCM monitors backup battery voltage when engine is running. DTC is set when PCM terminal No. 55 voltage is less than 2.5 volts for 2 seconds. Possible causes are

1. Faulty No. 11 ROOM (10 amp) fuse.
2. Open in wiring between positive battery terminal and PCM harness connector terminal No. 55.
3. Connector or terminal malfunction at PCM.
4. PCM malfunction.

DTC is set when command from PCM to immobilizer unit exceeds limit or there is no response from immobilizer unit. Possible causes are

1. Open or short in immobilizer system.
2. Immobilizer unit malfunction.
3. Immobilizer key transponder malfunction
4. Immobilizer coil malfunction.
5. PCM malfunction.

DTC is set when immobilizer system reprogram procedure was not performed after replacing PCM.

DTC is set when immobilizer system reprogram procedure (key IDs) was not performed after replacing PCM.

Code word stored in PCM and immobilizer unit does not match. DTC is set when immobilizer system reprogram procedure (code word) was not performed properly after replacing PCM.

Key ID stored in PCM and immobilizer unit does not match. DTC is set after replacing immobilizer unit.

DTC is set when PCM EEPROM is damaged.

DTC is set when PCM detects immobilizer system communication malfunction more than 3 times.

PCM monitors input voltage from generator and battery. DTC is set when engine is running and voltage is less than 8.5 volts for 5 seconds. Possible causes are

1. Open or short in White/Blue wire between generator harness connector terminal "P" and PCM harness connector terminal No. 30.
2. Open or Short in White/Red wire between generator harness connector terminal "D" and PCM harness connector terminal No. 53.
3. Missing drive belt.
4. Generator malfunction.
5. PCM malfunction.

PCM monitors input voltage from generator and battery. DTC is set when engine is running and generator voltage is more than 18.5 volts or battery voltage is more than 16 volts for 5 seconds. Possible causes are

1. Short to power.
2. Generator malfunction.
3. PCM malfunction.

PCM monitors input voltage from generator and battery. DTC is set when engine is running and generator voltage is more than 17 volts and battery voltage is less than 11 volts for 5 seconds. Possible causes are

1. Open circuit.
2. Battery malfunction.
3. PCM malfunction.

REFERENCE VOLTAGE

1. Disconnect appropriate sensor connector where voltage problem is suspected. Turn ignition on. Check voltage between harness connector reference voltage terminal and ground terminal. If voltage is 6 volts or less, go to next step. If voltage is more than 6 volts, go to step 13 .
2. Check voltage at battery terminals. If battery voltage is more than 10.5 volts, go to next step. If battery voltage is 10.5 volts or less, check charging system.
3. Turn ignition off. Check voltage between positive battery terminal and sensor harness connector ground terminal. If voltage is more than 10.5 volts and within 1 volt of battery voltage, go to next step. If battery voltage is 10.5 volts or less, or difference between measured voltage and battery voltage is more than 1 volt, go to step 8 .
4. Turn ignition on. Using scan tool, check ECT PID. If scan tool cannot access PID, go to next step. If scan tool can communicate with PCM and access PID, go to step 7 .
5. Turn ignition off. Disconnect TP sensor, EGR boost sensor, FTP sensor and PCM. Turn ignition on. Check voltage between PCM harness connector terminals 71 and 97 (+) and 24, 51, 76, 77 and 103 (-). If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open circuit between main relay and PCM terminals 71 and 97.
6. Turn ignition off. Check resistance between harness connector terminal 90 (Pink/Blue wire) and terminals 24, 51, 76, 77 and 103. If resistance is more than 10,000 ohms, recheck reference voltage. See step 1 . If resistance is 10,000 ohms or less, repair short to ground on Pink/Blue wire.
7. Turn ignition off. Disconnect suspect sensor and PCM. Check resistance between PCM harness connector terminal 90 (Pink/Blue wire) and suspect sensor harness connector reference voltage terminal. If resistance is less than 5 ohms, recheck reference voltage. See step 1 . If resistance is 5 ohms or more, repair open circuit in Pink/Blue wire. NOTE: Purpose of following step is to determine if scan tool is communicating with PCM.
8. Reconnect suspect sensor. Turn ignition on. Using scan tool, check ECT PID. If scan tool can access PID, go to next step. If scan tool cannot access ECT PID, go to step 11 .
9. If DTCs for two or more sensors listed are present, go to next step. If DTC(s) for only one sensor listed is present, repair open in ground circuit for suspect sensor. ECT sensor (DTCs P0116, P0117, P0118, P0125). EGR boost sensor (DTCs P0106, P0107, P0108). FTP sensor (DTCs P0451, P0452, P0453, P0454). Front HO2S (DTCs P0134, P0154, P1170, P1173). Rear HO2S (DTCs P0138, P0140, P0158, P1160). IAT sensor (DTCs P0111, P0112, P0113). TP sensor (DTCs P0122, P0123, P1122, P1123).
10. Turn ignition off. Disconnect scan tool and PCM. Check resistance of sensor ground circuit between harness connector terminal 91 (Brown/Yellow wire) and suspect sensor harness connector ground terminal. If resistance is less than 5 ohms, reconnect all components and return to appropriate DTC test. If resistance is 5 ohms or more, repair open circuit on Brown/Yellow wire.
11. Turn ignition off. Disconnect PCM connector. Check resistance between battery negative terminal and PCM harness connector terminals 24, 51, 76, 77 and 103. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on ground circuit.
12. Turn ignition off. Check resistance between harness connector ground terminal of each sensor listed and ground. If any resistance is more than 5 ohms, repair open ground circuit. If resistance is less than 5 ohms on all terminals, grounds are okay. Recheck reference voltage. See step 1 . TP sensor. EGR boost sensor. FTP sensor. ECT sensor. IAT sensor. Front HO2S. Rear HO2S.
13. Turn ignition off. Disconnect TP sensor, EGR boost sensor, FTP sensor and PCM. Turn ignition on. Check voltage between TP sensor harness connector reference voltage terminal and battery negative terminal. If voltage is .5 volt or more, repair reference voltage circuit short to power. If voltage is less than .5 volt, recheck reference voltage. See step 1 .
14. Clear DTCs and recheck symptom. If no problem is present, continue diagnosis. If reference voltage fault is present, check for service bulletins and on-line information. Repair as necessary. If fault is still present, replace PCM.

AFTER REPAIR PROCEDURE

Connect scan tool. Turn ignition off. Turn ignition on. Check for DTCs. Select CLEAR. Select TRIGGER. Select CANCEL. Turn ignition off.