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Engine Controls - Self-Diagnostics - 1.6L: Other Mazda Protege BJ

Testing & Diagnostics 6 illustrations ~6524 words

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

  1. 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.
  2. 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.
  3. Ensure scan tool meets OBD-II standard. Connect scan tool to 16-pin connector located at left side of steering column. Follow scan tool manufacturer's operating instructions to connect equipment and record freeze frame data.

PCM Adaptive Memory Drive Mode

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 27) 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 and cooling fan status.

Scheme 27

Scheme 27: PCM Adaptive Memory Drive Mode
Scheme 27: PCM Adaptive Memory Drive Mode

EGR Monitor Repair Verification Drive Mode

  1. Perform PCM adaptive memory drive mode first and go to next step. Ensure all electrical and A/C loads are off.
  2. Drive vehicle at specified speeds. (Scheme 28) 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 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 28

Scheme 28
Scheme 28

HO2S/TWC Monitor Repair Verification Drive Mode

  1. Perform PCM adaptive memory drive mode first and go to next step. Ensure all electrical and A/C loads are off.
  2. Drive vehicle at specified speeds. (Scheme 29) 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 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 29

Scheme 29
Scheme 29

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 14-X°F (-10-X°C). X = engine coolant temperature upper limit as determined by barometric pressure indicated in illustration. (Scheme 30) Intake air temperature is 14-140°F (-10-60°C). Barometric pressure is 72 kPa. Fuel Tank Level (FTL) PID V is.5-2.5 volts.
  2. Ensure all electrical and A/C loads are off. Start and operate engine at 3500 RPM to warm to normal operating temperature. Operate vehicle as specified. (Scheme 31) 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 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 30

Scheme 30
Scheme 30

Scheme 31

Scheme 31
Scheme 31

SUMMARY

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

Condition

DTC is set when Powertrain Control Module (PCM) detects low input voltage from ground side of front HO2S heater circuit after PCM turns HO2S heater circuit off. This is an intermittent monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Front HO2S malfunction.
  2. Open or short circuit between front HO2S and PCM.
  3. Open circuit between front HO2S and ignition switch.
  4. Loose connection at connectors.
  5. PCM malfunction.

DTC is set when Powertrain Control Module (PCM) detects high input voltage from ground side of front HO2S heater circuit after PCM turns HO2S heater circuit on. This is an intermittent monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Short to power between front HO2S and PCM.
  2. Shorted front HO2S or PCM.
  3. PCM malfunction.

DTC is set when Powertrain Control Module (PCM) detects low input voltage from ground side of rear HO2S heater circuit after PCM turns HO2S heater circuit off. This is an intermittent monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Rear HO2S malfunction.
  2. Open or short circuit between rear HO2S and PCM.
  3. Open circuit between rear HO2S and ignition switch.
  4. Loose connection at connectors.
  5. PCM malfunction.

DTC is set when Powertrain Control Module (PCM) detects high input voltage from ground side of rear HO2S heater circuit after PCM turns HO2S heater circuit on. This is an intermittent monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Short to power between rear HO2S and PCM.
  2. Shorted rear HO2S or PCM.
  3. PCM malfunction.

DTC is set when input voltage from MAF sensor is less than .21 volt. This is a continuous monitor. MIL is illuminated when PCM detects malfunction during first drive cycle. Possible causes are

  1. MAF sensor malfunction.
  2. Open or short circuit between Powertrain Control Module (PCM) and MAF sensor.
  3. Open circuit between main relay and MAF sensor.

DTC is set when Powertrain Control Module (PCM) detect input voltage from MAF sensor is more than 4.9 volts. This is a continuous monitor. MIL is illuminated when PCM detects malfunction during first drive cycle. Possible causes are

  1. MAF sensor malfunction.
  2. Poor connection.
  3. Short to power between PCM and MAF sensor.

Powertrain Control Module (PCM) monitors barometric pressure by monitoring difference between intake manifold vacuum and atmospheric pressure at idle. PCM monitors atmospheric pressure at idle by using EGR boost sensor and by switching EGR boost sensor solenoid. DTC is set when barometric pressure variation is less than 1.9 in. Hg. This is a continuous monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. EGR boost sensor malfunction.
  2. EGR boost sensor solenoid valve malfunction.
  3. Loose, damaged, misrouted or plugged vacuum hoses between EGR boost sensor and EGR boost sensor solenoid valve, and between EGR valve and EGR boost sensor solenoid valve.
  4. PCM malfunction.

Scheme 32

Scheme 32: Diagnosis & Repair Procedure
Scheme 32: Diagnosis & Repair Procedure
  1. Ensure FREEZE FRAME DATA has been recorded. Check for related service bulletins. Repair as necessary and go to next step.
  2. Turn ignition off and start engine. Using scan tool, check for DTCs. If DTC P1487 is not present, go to next step. If DTC P1487 is present, diagnose and repair as necessary. See «DTC P1487: EGR BOOST SENSOR SOLENOID VALVE CIRCUIT MALFUNCTION»(ref-11776-S26574895122000112700000) .
  3. Check for DTCs in FREEZE FRAME data. If DTC P0106 is present, go to next step. If DTC P0106 is not present, go to TROUBLE SHOOTING in BASIC DIAGNOSTIC PROCEDURES article.
  4. Check for loose, damaged, misrouted or plugged vacuum hoses between EGR boost sensor and EGR boost sensor solenoid valve, and between EGR boost sensor solenoid valve and intake manifold. If vacuum hoses are okay, go to next step. If any problem is present, repair or replace as necessary and go to step 8 .
  5. Check for plugged EGR boost sensor air filter. Repair or replace as necessary and go to step 8 . If EGR boost sensor air filter is okay, go to next step.
  6. Disconnect EGR boost sensor hose. Disconnect EGR boost sensor solenoid valve hoses. Connect vacuum pump to EGR boost sensor solenoid valve lower port. Apply vacuum. Vacuum should hold. Turn ignition on. Using scan tool, access SIMULATION TEST, then turn CDCV PID on. If EGR boost sensor solenoid valve releases vacuum, go to next step. If purge solenoid valve does not release vacuum, replace purge solenoid valve. Go to step 8 .
  7. Check EGR boost sensor operation. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. Replace as necessary and go to next step. If EGR boost sensor is okay, go to next step.
  8. Reconnect all connectors. Turn ignition on. Clear DTC from memory. See «CLEARING DIAGNOSTIC TROUBLE CODES»(ref-11776-S18637645172001053100000) under SELF-DIAGNOSTIC SYSTEM. Perform PCM adaptive memory drive mode, EGR monitor repair verification drive mode and HO2S/TWC monitor repair verification drive mode. See «DRIVE MODES»(ref-11776-S39379847722001053100000) under SELF-DIAGNOSTIC SYSTEM. Recheck for DTCs. See «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-11776-S08888967292001053100000) under SELF-DIAGNOSTIC SYSTEM. If DTC P0106 is still present, replace PCM. If DTC P0106 is not present, go to next step.
  9. Cycle ignition from off to on. Check for DTCs. See «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-11776-S08888967292001053100000) under SELF-DIAGNOSTIC SYSTEM. If any other DTC is present, go to appropriate test.

PCM monitors voltage from EGR boost sensor when intake air temperature is more than 50°F (10°C) and EGR boost sensor solenoid is turned off (atmospheric pressure is applied to sensor). Code is set when input voltage from EGR boost sensor is less than .35 volts. This is a continuous monitor. MIL is illuminated when PCM detects malfunction during first drive cycle. Possible causes are

  1. EGR boost sensor malfunction.
  2. Poor connections.
  3. Open or short circuit between EGR boost sensor and PCM.
  4. PCM malfunction.

PCM monitors voltage from EGR boost sensor when intake air temperature is more than 50°F (10°C) and EGR boost sensor solenoid is turned off (atmospheric pressure is applied to sensor). Code is set when input voltage from EGR boost sensor is more than 4.92 volts. This is a continuous monitor. MIL is illuminated when PCM detects malfunction during first drive cycle. Possible causes are

  1. EGR boost sensor malfunction.
  2. Open or short circuit between EGR boost sensor and PCM.
  3. PCM malfunction.

Conditions

DTC is set when intake air temperature is 104° F (40° C) greater than engine coolant temperature and ignition is on. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. IAT sensor malfunction.
  2. Poor connections at IAT sensor and PCM.
  3. PCM malfunction.

DTC is set when voltage from IAT sensor is less than .15 volts and ignition is on. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during first drive cycle. Possible causes are

  1. IAT sensor malfunction.
  2. Short circuit between IAT sensor and PCM.
  3. PCM malfunction.

DTC is set if input voltage from IAT is more than 4.8 volts. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during first drive cycle. Possible causes are

  1. IAT sensor malfunction.
  2. Open or short circuit between IAT sensor and PCM.
  3. PCM malfunction.

DTC is set if input voltage from ECT sensor is less than 0.2 volt. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during first drive cycle. Possible causes are

  1. ECT sensor malfunction.
  2. Short circuit between ECT sensor and PCM.
  3. PCM malfunction.

DTC is set if input voltage from ECT sensor is more than 4.94 volts. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during first drive cycle. Possible causes

  1. ECT sensor malfunction.
  2. Open or short circuit between ECT sensor and PCM.
  3. PCM malfunction.

DTC is set when input voltage from TP sensor is less than 0.1 volt after engine is started. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during first drive cycle. Possible causes are

  1. TP sensor malfunction.
  2. Open or short circuit between PCM and TP sensor.
  3. PCM malfunction.

DTC is set when input voltage from TP sensor is more than 4.77 volts after engine starts. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during first drive cycle. Possible causes are

  1. TP sensor malfunction.
  2. Open or short circuit between PCM and TP sensor.
  3. PCM malfunction.

DTC is set when engine coolant temperature has not appropriately increased after engine is started cold and default period of time has passed. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Engine coolant temperature (ECT) sensor malfunction.
  2. PCM malfunction.

DTC is set when HO2S signal fluctuates at longer intervals than allowed during normal driving conditions. For this DTC to set the vehicle must be under the following conditions: Engine load should be at 20-59 percent at 2000 RPM, engine speed should be 1410-4000 RPM, vehicle speed should be more than 2.34 MPH and engine coolant temperature should be more than 14°F (-10°C). This is an intermittent monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are: .

  1. Front HO2S.
  2. Pressure Regulator Control (PRC) solenoid valve malfunction.
  3. Fuel pressure regulator malfunction.
  4. Fuel pump malfunction.
  5. Fuel filter plugged.
  6. Fuel leak at fuel line at distribution pipe and fuel pump.
  7. Fuel return line plugged.
  8. Exhaust system leak.
  9. Purge solenoid valve malfunction.
  10. Purge solenoid hoses improperly connected.
  11. Low engine compression.
  12. Engine malfunction.

DTC is set when front HO2S signal voltage does not exceed .55 volt for 94.4 seconds after engine coolant temperature has reached more than 176°F (80°C) and engine speed is more than 1500 RPM. Powertrain Control Module (PCM) checks front HO2S operation during HO2S/TWC monitor repair verification drive mode. See DRIVE MODES under SELF-DIAGNOSTIC SYSTEM. This is a continuous monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Front HO2S.
  2. Exhaust leak.
  3. Open or short circuit between front HO2S and PCM.
  4. Low engine compression.
  5. Engine malfunction.

DTC is set when rear HO2S input exceeds .45 volt for 6 seconds during decelerations (fuel cut). This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Rear HO2S malfunction.
  2. Short circuit between rear HO2S and PCM.

DTC is set when rear HO2S signal voltage does not exceed .55 volt for 54.2 seconds after engine coolant temperature has reached more than 176°F (80°C) and engine speed is more than 1500 RPM. Powertrain Control Module (PCM) checks rear HO2S operation during HO2S/TWC monitor repair verification drive mode. See DRIVE MODES under SELF-DIAGNOSTIC SYSTEM. This is a continuous monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Rear HO2S.
  2. Exhaust system leak.
  3. Open or short circuit between rear HO2S and PCM.
  4. Low engine compression.
  5. Engine malfunction.

DTC is set when short term or long term fuel trim values do not meet specified value while PCM adaptive memory drive mode is running. See DRIVE MODES under SELF-DIAGNOSTIC SYSTEM. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Misfire.
  2. Front HO2S malfunction.
  3. Pressure Regulator Control (PRC) solenoid valve malfunction.
  4. Fuel pressure regulator malfunction.
  5. Fuel injector malfunction.
  6. Fuel pump malfunction.
  7. Fuel filter plugged.
  8. Fuel leak at fuel line at distribution pipe and fuel pump.
  9. Fuel return line plugged.
  10. Exhaust system leak.
  11. Purge solenoid valve malfunction.
  12. Purge solenoid hoses improperly connected.
  13. Low compression.

DTC is set when short term or long term fuel trim values do not meet specified value while PCM adaptive memory drive mode is running. See DRIVE MODES under SELF-DIAGNOSTIC SYSTEM. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Misfire.
  2. Front HO2S malfunction.
  3. Pressure Regulator Control (PRC) solenoid valve malfunction.
  4. Fuel pressure regulator malfunction.
  5. Fuel pump malfunction.
  6. Fuel return line plugged.
  7. Exhaust system leak.
  8. Purge solenoid valve malfunction.
  9. Purge solenoid hoses improperly connected.
  10. PCV valve malfunction.

Powertrain Control Module (PCM) monitors Crankshaft Position (CKP) sensor input signal interval time. PCM detects a misfire in a specific cylinder by calculating change of CKP interval time for each cylinder. While engine is operating, PCM counts number of misfires that occur during 200 crankshaft revolutions and during 1000 crankshaft revolutions in order to calculate a misfire ratio for each crankshaft revolution. If misfire ratio exceeds a preprogrammed criteria, PCM determines that a misfire has occurred which can damage catalytic converter and will set a DTC. This is a continuous monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. CKP sensor malfunction.
  2. Camshaft Position (CMP) sensor malfunction.
  3. Ignition coil malfunction.
  4. Secondary ignition system malfunction.
  5. Mass Airflow (MAF) sensor malfunction.
  6. Vacuum leak between MAF sensor and plenum chamber.
  7. Fuel pump malfunction.
  8. Fuel pressure regulator malfunction.
  9. Plugged fuel line.
  10. Plugged fuel filter.
  11. Fuel lines leaking.
  12. Purge solenoid valve malfunction.
  13. PCV valve malfunction.
  14. EGR system malfunction.
  15. Vacuum hoses damaged or improperly connected.
  16. Poor connector connection or wiring problems.

Powertrain Control Module (PCM) monitors Crankshaft Position (CKP) sensor input signal interval time. PCM detects a misfire in a specific cylinder by calculating change of CKP interval time for each cylinder. While engine is operating, PCM counts number of misfires that occur during 200 crankshaft revolutions and during 1000 crankshaft revolutions in order to calculate a misfire ratio for each crankshaft revolution. If misfire ratio exceeds a preprogrammed criteria, PCM determines that a misfire has occurred which can damage the catalytic converter and will set a DTC. DTC P0301 is set when cylinder No. 1 misfire is detected. DTC P0302 is set when cylinder No. 2 misfire is detected. DTC P0303 is set when cylinder No. 3 misfire is detected. DTC P0304 is set when cylinder No. 4 misfire is detected. This is a continuous monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Spark plug malfunction.
  2. Secondary ignition system malfunction.
  3. Fuel injector malfunction.
  4. Vacuum leak between plenum chamber and cylinder head.
  5. Low engine compression.
  6. Poor connector connection or wiring problems.

DTC is set when there is no signal input from Crankshaft Position (CKP) sensor for 4.2 seconds while Mass Airflow (MAF) is 2.43 grams/sec. or more. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during first drive cycle. Possible causes are

  1. CKP sensor malfunction.
  2. Open or short circuit between PCM and CKP.
  3. Open or short circuit between main relay and CKP.
  4. Crankshaft pulley malfunction.

DTC is set when the difference in intake manifold pressure between open EGR and closed EGR is too small. This is an intermittent monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. EGR valve malfunction.
  2. EGR boost sensor malfunction.
  3. EGR boost sensor solenoid valve malfunction.
  4. EGR valve base gasket improperly installed.
  5. Powertrain Control Module (PCM) malfunction.

DTC is set when the difference in intake manifold pressure between open EGR and closed EGR is too large. This is an intermittent monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. EGR valve base gasket damaged or missing.
  2. Powertrain Control Module (PCM) malfunction.

DTC is set when value from rear HO2S becomes closer to value from front HO2S. This is monitored when engine speed is 1500-3000 RPM, vehicle speed is 17.3-74.5 MPH and vehicle is under 15-48 percent load. This is an intermittent monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Three Way Catalytic (TWC) converter deterioration or malfunction.
  2. Exhaust system leak.
  3. Loose rear HO2S.
  4. Loose front HO2S.
  5. Front HO2S malfunction.

DTC is set when Powertrain Control Module (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. This is monitored when following conditions are met

  1. Fuel tank pressure is .38-1.15 in. Hg.
  2. Fuel remaining is 15-85 percent of total capacity.
  3. Intake air temperature is 14-140°F (-10-60°C) and engine coolant temperature is 14.0-90.5°F (-10.0-32.5°C) when engine is first started.
  4. Atmospheric pressure is more than 21.4 in. Hg.
  5. Vehicle speed is 24.5-74.7 MPH.
  6. Engine speed is 1000-4000 RPM.
  7. Calculated load is 9.4-65 percent.
  8. Throttle opening angle is 3.1-12.5 percent.

This is an intermittent monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Purge solenoid valve malfunction.
  2. CDCV malfunction.
  3. Fuel pressure control valve malfunction.
  4. Loose or damaged fuel filler cap.
  5. Charcoal canister malfunction.
  6. Catch tank malfunction.
  7. Rollover valve malfunction.
  8. Cracked fuel tank.
  9. Poorly installed fuel tank components.
  10. EVAP hoses damaged or loose.

DTC is set when Powertrain Control Module (PCM) detects input voltage from purge solenoid valve is to low or to high. This is a diagnostic support DTC, monitored once per ignition key cycle. MIL is not illuminated when PCM detects malfunction. Possible causes are

  1. Purge solenoid valve malfunction.
  2. Open circuit between main relay and purge solenoid valve.
  3. Open or short circuit between purge solenoid valve and PCM.
  4. PCM malfunction.

Powertrain Control Module (PCM) detects not enough or too much fuel tank pressure difference when operating evaporative leak monitor or closing purge solenoid valve. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Fuel Tank Pressure (FTP) sensor malfunction.
  2. Purge solenoid valve malfunction.
  3. Canister Drain Cut Valve (CDCV) malfunction.
  4. Poor connection at CDCV, fuel tank pressure sensor or PCM.
  5. Short in wiring.
  6. Plugged charcoal canister malfunction.

DTC is set when engine coolant temperature is less than 176°F (80°C) and fuel tank pressure sensor input is less than .2 volt. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Fuel Tank Pressure (FTP) sensor malfunction.
  2. Open or short circuit between fuel tank pressure sensor and PCM.
  3. PCM malfunction.

DTC is set when engine coolant temperature is less than 176°F (80°C) and fuel tank pressure sensor input is more than 4.8 volts. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Fuel Tank Pressure (FTP) sensor malfunction.
  2. Open or short circuit between fuel tank pressure sensor and Powertrain Control Module (PCM).

DTC is set when Powertrain Control Module (PCM) detects high pressure (no vacuum) in fuel tank, measured immediately after purge control is stopped with Canister Drain Cut Valve (CDCV) closed. This is monitored when following conditions are met

  1. Fuel tank pressure is -.1.16 in. Hg.
  2. Fuel remaining is 15-85 percent of total capacity.
  3. Intake air temperature is 14-140°F (-10-60°C) and engine coolant temperature is 14.0-90.5°F (-10.0-32.5°C) when engine is first started.
  4. Atmospheric pressure is more than 21.3 in. Hg.
  5. Vehicle speed is 24.5-74.7 MPH.
  6. Engine speed is 1000-4000 RPM.
  7. Calculated load is 9.4-65 percent.
  8. Throttle opening angle is 3.1-12.5 percent.

This is an intermittent monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Purge solenoid valve malfunction.
  2. CDCV malfunction.
  3. Loose, missing or defective fuel filler cap.
  4. Charcoal canister malfunction.
  5. Catch tank malfunction.
  6. Rollover valve malfunction.
  7. Cracked fuel tank.
  8. Poorly installed fuel tank components.
  9. Evaporative hoses damaged or loose.
  10. Fuel Tank Pressure (FTP) sensor malfunction.

DTC is set when fuel gauge sending unit operation is 5 percent less than Powertrain Control Module (PCM) calculated fuel consumption, when fuel consumption is more than 4.6 gallons. This is a continuous monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible cause is: Fuel gauge sending unit malfunction.

DTC is set when fuel gauge sending unit voltage is less than .08 volt for 5 seconds. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Fuel gauge sending unit malfunction.
  2. Short in wiring.
  3. PCM malfunction.

DTC is set when input voltage from fuel level sensor is more than 4.9 volts for 5 seconds. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Fuel gauge sending unit malfunction.
  2. Open or poor connection in wiring.
  3. PCM malfunction.

DTC is set when fuel gauge sending unit input voltage changes excessively for 14 seconds when vehicle is stopped and engine is running. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible cause is: Fuel gauge sending unit malfunction.

DTC is set when cooling fan relay coil control circuit input is to low or to high. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Cooling fan relay malfunction.
  2. Open or short circuit between cooling fan relay and PCM.
  3. Open circuit between cooling fan relay and main relay.
  4. PCM malfunction.

DTC is set when Powertrain Control Module (PCM) does not detect vehicle speed signal. This is monitored when engine speed is more than 2000 RPM, engine load is more than 40 percent, and transmission is in any position except neutral. This is a continuous monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. PCM malfunction.
  2. Instrument cluster malfunction.
  3. Anti-lock Brake System Hydraulic Unit/Control Module (ABS HU/CM) malfunction.
  4. Open or short circuit between instrument cluster and PCM.
  5. Vehicle Speed Sensor (VSS) malfunction.
  6. Open or short circuit between VSS and instrument cluster.

DTC is set when actual engine speed is 100 RPM less than programed target speed for more than 14 seconds with brake pedal depressed and front wheels in straight ahead position. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Idle Air Control (IAC) valve malfunction.
  2. Air filter or intake passage plugged.
  3. A/C relay control circuit malfunction.
  4. Generator control circuit malfunction.
  5. Purge solenoid valve malfunction.
  6. Low engine compression or to much blow by.
  7. PCM malfunction.

DTC is set when actual engine speed is 200 RPM greater than programed target speed for more than 14 seconds with brake pedal depressed and front wheels in straight ahead position. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Idle Air Control (IAC) valve malfunction.
  2. Throttle cable misadjustment.
  3. Throttle valve malfunction.
  4. Vacuum hoses misrouted.
  5. PCM malfunction.

DTC is set when vehicle speed is more than 37.3 MPH, coolant temperature is 140°F (60°C) or more and Powertrain Control Module (PCM) receives a low power steering switch signal continuously for one minute. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Power Steering Pressure (PSP) switch malfunction.
  2. Short circuit between PSP switch and PCM.
  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. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Brake switch malfunction.
  2. Open circuit between brake switch and PCM.
  3. PCM malfunction.

DTC is set when Powertrain Control Module (PCM) has not received a voltage change from clutch switch when clutch pedal is activated 10 times, vehicle speed is 19 MPH or more and vehicle is stopped repeatedly. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Clutch switch malfunction.
  2. Open circuit between clutch switch and PCM.
  3. PCM malfunction.

DTC is set when Powertrain Control Module (PCM) has not received a neutral switch signal, when vehicle is driven at speeds above 19 MPH, stopped repeatedly and clutch pedal is depressed 10 times. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Neutral switch malfunction.
  2. Open in wiring between neutral switch and PCM.
  3. PCM malfunction.

DTC is set if input voltage from MAF sensor is less than expected (less than .63 lb/min) for 5 seconds when throttle opening angle is less than 50 percent and engine running. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. MAF sensor malfunction.
  2. TP sensor malfunction.
  3. Corrosion or voltage drop on signal circuit.

DTC is set if input voltage from MAF sensor is more than 66.6 grams/sec. for 5 seconds when engine speed is less than 2000 RPM and engine coolant temperature is more than 176°F (80°C). This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. MAF sensor malfunction.
  2. Corrosion or voltage drop in signal circuit.

DTC is set if Throttle Position (TP) sensor position is less than 12.5 percent for 5 seconds when engine coolant is more than 176°F (80°C) and Mass Airflow (MAF) sensor reading is more than 58.3 grams/sec. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. TP sensor malfunction.
  2. Corrosion or voltage drop in signal circuit.
  3. Powertrain Control Module (PCM) function.

DTC is set if TP sensor position is more than 50 percent for 5 seconds when engine speed is more than 500 RPM and Mass Airflow (MAF) sensor reading is less than 4.8 grams/sec. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. TP sensor malfunction.
  2. MAF sensor malfunction.
  3. Poor connection or voltage drop in circuit.
  4. PCM malfunction.

DTC is set when front HO2S signal voltage is more than or less than .45 volt and remains unchanged for 42.9 seconds with engine speed more than 1500 RPM and engine coolant temperature more than 176°F (80°C). This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Front HO2S.
  2. Fuel injector malfunction.
  3. Fuel pressure regulator malfunction.
  4. Fuel pump malfunction
  5. Fuel delivery or return hose plugged or leaking.
  6. Fuel filter plugged.
  7. Vacuum leak.
  8. PCV valve malfunction.
  9. Purge solenoid valve malfunction.
  10. Purge solenoid hoses improperly installed.
  11. Ignition coil malfunction.
  12. Low engine compression.
  13. Engine malfunction.

DTC is set when Powertrain Control Module (PCM) detects low or high input voltage from PRC solenoid valve. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during first drive cycle. Possible causes are

  1. PRC solenoid valve malfunction.
  2. Short or open circuit between PCM and PRC solenoid valve.
  3. Open circuit between PRC solenoid valve and main relay.
  4. PCM malfunction.

DTC is set when there is no signal input from Camshaft Position (CMP) sensor for 12 crankshaft revolutions. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during first drive cycle. Possible causes are

  1. CMP sensor malfunction.
  2. Dirty CMP sensor.
  3. Loose CMP sensor connector.
  4. Open or short circuit between main relay and CMP sensor.
  5. Open or short circuit between CMP sensor and PCM.
  6. Open circuit between CMP sensor and ground.

DTC is set when Powertrain Control Module (PCM) detects low or high voltage in CDCV system circuit with ignition on. This is a diagnostic support DTC, monitored once per key cycle. Malfunction Indicator Light (MIL) does not illuminate. Possible causes are

  1. CDCV malfunction.
  2. Open circuit between main relay and CDCV.
  3. Open or short circuit between PCM and CDCV.
  4. PCM malfunction.

DTC is set when Powertrain Control Module (PCM) detects fuel tank pressure is low for 10 seconds when intake air temperature is more than 14°F (-10°C), engine coolant temperature was less than 95°F (35°C) when engine was first started and now is 212°F (100°C), and vehicle speed is 61.9 MPH or less. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Canister Drain Cut Valve (CDCV) malfunction.
  2. EVAP air filter plugged.
  3. Charcoal canister malfunction.
  4. Plugged EVAP hoses.
  5. Fuel Tank Pressure (FTP) sensor malfunction.
  6. Purge solenoid valve malfunction.

DTC is set when PCM detects input voltage from EGR boost sensor solenoid is to low or to high just after turning ignition on. This is a diagnostic support DTC, monitored once per ignition key cycle. MIL is not illuminated when PCM detects malfunction. Possible causes are

  1. EGR boost sensor solenoid valve malfunction.
  2. Open or short circuit between EGR and PCM.
  3. Open circuit between EGR and main relay.
  4. PCM malfunction.

DTC is set when PCM detects input voltage from EGR valve coil No. 1 is to low or to high just after turning ignition on. This is a diagnostic support DTC, monitored once per ignition key cycle. MIL is not illuminated when PCM detects malfunction. Possible causes are

  1. EGR valve malfunction.
  2. Open or short circuit between PCM and EGR valve.
  3. Open circuit between main relay and EGR valve.
  4. PCM malfunction.

DTC is set when PCM detects input voltage from EGR valve coil No. 2 is to low or to high just after turning ignition on. This is a diagnostic support DTC, monitored once per ignition key cycle. MIL is not illuminated when PCM detects malfunction. Possible causes are

  1. EGR valve malfunction.
  2. Open or short circuit between PCM and EGR valve.
  3. Open circuit between main relay and EGR valve.
  4. PCM malfunction.

DTC is set when PCM detects input voltage from EGR valve coil No. 3 is to low or to high just after turning ignition on. This is a diagnostic support DTC, monitored once per ignition key cycle. MIL is not illuminated when PCM detects malfunction. Possible causes are

  1. EGR valve malfunction.
  2. Open or short circuit between PCM and EGR valve.
  3. Open circuit between main relay and EGR valve.
  4. PCM malfunction.

DTC is set when PCM detects input voltage from EGR valve coil No. 4 is to low or to high just after turning ignition on. This is a diagnostic support DTC, monitored once per ignition key cycle. MIL is not illuminated when PCM detects malfunction. Possible causes are

  1. EGR valve malfunction.
  2. Open or short circuit between PCM and EGR valve.
  3. Open circuit between main relay and EGR valve.
  4. PCM malfunction.

DTC is set when PCM detects that IAC valve circuit current is less than 100 milliamps or more than 4.5 amps for one second when IAC duty cycle is 18-70 percent. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during first drive cycle. Possible causes are

  1. IAC valve malfunction.
  2. Open or short circuit between IAC valve and PCM.
  3. PCM malfunction.

DTC is set when PCM detects air flow is more than 30 grams/sec. when engine speed is more than 3000, engine coolant temperature is more than 176°F (80°C), and throttle valve opening angle is more than 75 percent. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are: Possible causes are

  1. ECT sensor malfunction.
  2. MAF sensor malfunction.
  3. IAT sensor malfunction.
  4. EGR boost sensor malfunction.
  5. TP sensor malfunction.
  6. CKP sensor malfunction.
  7. VTCS solenoid valve malfunction.
  8. VTCS shutter valve stuck closed.
  9. VTCS shutter valve actuator stuck closed.
  10. Short circuit between PCM and VCTS solenoid valve.
  11. PCM malfunction.

DTC is set when PCM detects less than 2.5 volts for 2 seconds at power supply terminal after engine is started. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during first drive cycle. Possible causes are

  1. Open or short circuit between battery and PCM.
  2. PCM malfunction.

DTC is set when PCM detects low voltage input from VTCS solenoid valve when VTCS solenoid valve is off. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Open or Short circuit between VICS solenoid valve and PCM.
  2. Open circuit between VICS solenoid valve and main relay.
  3. VICS solenoid valve malfunction.
  4. PCM malfunction.

DTC is set when PCM detects high voltage input from VTCS solenoid valve when VTCS solenoid valve is on, engine speed is more than 3250 RPM, engine coolant temperature is less than 149° F (65°C) and throttle valve opening angle is less than 14 percent (A/T) or 12.5 percent (M/T - engine speed 2500 RPM). This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are

  1. Open or Short circuit between VICS solenoid valve and PCM.
  2. Open circuit between VICS solenoid valve and main relay.
  3. VICS solenoid valve malfunction.
  4. PCM malfunction.

DTC is set when PCM detects generator output voltage is less than 8.5 volts or generator current more than 19.5 amps with engine running. Possible causes are

  1. Open or short circuit between generator and PCM.
  2. Loose or broken generator drive belt.
  3. Generator malfunction.
  4. PCM malfunction.

DTC is set when PCM detects positive battery voltage is less than 8 volts for 5 seconds. Possible causes are

  1. Open circuit between battery positive terminal and PCM.
  2. PCM malfunction.

DTC is set when Powertrain Control Module (PCM) detects generator output is more than 18.5 volts or battery voltage is more than 16 volts for 5 seconds. Possible causes are

  1. Short circuit between generator and PCM.
  2. Generator malfunction (overcharge).
  3. PCM malfunction.

DTC is set when Powertrain Control Module (PCM) detects generator output is more than 17 volts and battery voltage is less than 11 volts for 5 seconds with engine running. Possible causes are

  1. Open circuit between battery and generator.
  2. Battery malfunction.
  3. PCM malfunction.

Incorrect reference voltage. Possible causes are

  1. EGR boost sensor, reference voltage circuit malfunction.
  2. Fuel Tank Pressure (FTP) sensor, reference voltage circuit malfunction.
  3. Throttle Position (TP) sensor, reference voltage circuit malfunction.

More articles — Engine Controls - Self-Diagnostics - 1.6L