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Engine Controls - Self-Diagnostics: Other Mazda 626 GF

Testing & Diagnostics 1 illustration ~13801 words

KOEO & KOER DTCs

These DTCs indicate faults are present at time of testing. A hard fault may cause CHECK ENGINE or Malfunction Indicator Light (MIL) to go on and remain on until fault is repaired. If KOEO or KOER DTCs are retrieved during KOEO ON-DEMAND SELF-TEST or KOER ON-DEMAND SELF-TEST, go to appropriate test.

Continuous Memory DTCs

Continuous Memory DTCs are retrieved after performing KOER ON-DEMAND SELF-TEST. Unlike KOEO or KOER self-tests, which can only be activated on-demand, Continuous Memory Self-Test is always active. A fault may or may not be present at time of checking for Continuous Memory DTCs. This self-test is helpful in diagnosing intermittent problems.

After noting and/or repairing fault, clear DTCs from memory. See CLEARING CODES . Intermittent faults may be caused by a sensor, connector or wiring-related problem. See TROUBLE SHOOTING - NO CODES article.

Note. Continuous Memory DTCs should be recorded when retrieved. These DTCs may be used to identify intermittent problems that exist after all KOEO and KOER DTCs have been repaired. Some Continuous Memory DTC faults may not be valid after KOEO and KOER DTCs are serviced.

RETRIEVING CODES

Fault codes are retrieved from EEC-V system through Data Link Connector (DLC), located below instrument panel, left of steering wheel. (Scheme 15) Self-diagnostic test procedures are for use with New Generation Star (NGS) scan tool. If a generic scan tool is used, ensure scan tool is certified to OBD-II standard.

Scheme 15

Scheme 15: RETRIEVING CODES
Scheme 15: RETRIEVING CODES

Pass Codes

SYSTEM PASS indicates no DTCs were recorded in that portion of test. If SYSTEM PASS is not retrieved in KOEO ON-DEMAND SELF-TEST, DTCs retrieved during KOER ON-DEMAND SELF-TEST may not be valid.

These DTCs result from information stored by PCM during continuous self-test monitoring. Use these DTCs for diagnosis only when KOEO ON-DEMAND SELF-TEST and KOER ON-DEMAND SELF-TEST result in SYSTEM PASS and all steps under QUICK TEST are successfully completed. These DTCs indicate faults previously recorded. Fault may or may not be currently present.

CLEARING CODES

CAUTIONDO NOT disconnect vehicle battery to clear DTCs. This will erase operating information from Keep-Alive Memory (KAM). To clear KAM, see RESETTING KEEP-ALIVE MEMORY (KAM) .

VISUAL CHECK

Perform the following, and make all necessary repairs before continuing with QUICK TEST

  1. Inspect air cleaner and inlet ducts.
  2. Inspect system wiring harness for proper connections, bent or broken pins, corrosion, loose wires and proper routing.
  3. Check Powertrain Control Module (PCM), sensors and actuators for physical damage.
  4. Check engine coolant for proper level and mixture.
  5. Check transmission fluid level and quality.

VEHICLE PREPARATION & EQUIPMENT HOOKUP

Apply parking brake, and place shift lever in Park (A/T) or Neutral (M/T) position. Block drive wheels. Turn off all electrical accessories. Ensure engine is at normal operating temperature. If vehicle is equipped with an auxiliary powertrain control system (RPM control), it must be turned off when performing any self-test procedure. Connect appropriate test equipment to vehicle as follows.

ADDITIONAL SYSTEM FUNCTIONS

Note. Additional diagnostic system features are available to help diagnose driveability problems and service EEC-V systems.

Accessing Generic OBD-II PIDs

Turn ignition off. Ensure test equipment is properly attached. Program scan tool using the following steps

  1. Select VEHICLE & ENGINE SELECTION menu.
  2. Select NEW VEHICLE, YEAR & MODEL.
  3. Select GENERIC OBD-II OPTIONS. Press CONT button if monitors are not complete.
  4. Select PID/DATA MONITOR.
  5. Turn ignition on or start engine and allow to idle.
  6. Follow operating instructions from scan tool menu.
  7. Select PIDs and press START to begin monitoring. If PID value is not as specified, perform appropriate SYSTEM TEST.

Accessing EEC-V Specific PIDs

Turn ignition off. Ensure test equipment is properly attached. Program scan tool using the following steps

  1. Select VEHICLE & ENGINE SELECTION menu.
  2. Select NEW VEHICLE, YEAR & MODEL.
  3. Select DIAGNOSTIC DATA LINK.
  4. Select PCM-POWERTRAIN CONTROL MODULE.
  5. Select PID/DATA MONITOR & RECORD.
  6. Turn ignition on or start engine and allow to idle.
  7. Follow operating instructions from scan tool menu.
  8. Select PIDs and press START to begin monitoring. If PID value is not as specified, perform appropriate SYSTEM TEST.

FREEZE FRAME DATA MODE

This mode allows access to emission related data values from specific generic PIDs. These values are immediately stored in continuous memory when an emission related fault occurs. This provides a snapshot of the conditions that were present when the fault occurred. Freeze frame will be stored until PCM memory is erased.

To access FREEZE FRAME DATA MODE, turn ignition off. Ensure test equipment is properly attached. Program scan tool using the following steps

  1. Select VEHICLE & ENGINE SELECTION menu.
  2. Select NEW VEHICLE, YEAR & MODEL.
  3. Follow operating instructions from scan tool menu.
  4. Select GENERIC OBD-II FUNCTIONS. Press CONT button if OBD-II monitors are not complete.
  5. Turn ignition on.
  6. Select FREEZE FRAME PID TESTS.

FAILURE MODE EFFECTS MANAGEMENT (FMEM)

FMEM mode allows system operation when sensors fail or transmit signals that are out of normal operating range. During FMEM mode, PCM substitutes a mid-range signal for defective sensor while continuing to monitor sensor. If faulty sensor signals return to normal operating range, PCM will use those signals. Depending on specific failure, a fault code may be set in PCM memory.

Verification Drive Cycle

Note. 8 hour timer may be shortened by 3 hours depending on conditions. If soak period is shortened, PCM may detect a malfunction even after repairs. This may happen under warm or hot conditions.

Cold soak vehicle for 8 hours before performing EVAP test. Connect scan tool. Turn all accessories off. Start engine. Accelerate to 40 MPH within 20 seconds. Drive vehicle at 35-45 MPH for 5.5 minutes. Accelerate to 50-60 MPH within 10 seconds and remain at that speed for at least 2 minutes. Stop vehicle and allow to idle for 20 seconds. Using scan tool, check drive mode completion status. If test is not complete, repeat test from engine start. If test is complete, check test results. If results are okay, ensure no DTCs are present. If results are not okay, repairs are not complete.

To bypass 8 hour timer, cool fuel tank as much as possible. Connect scan tool. Access CLEAR DIAGNOSTIC CODES. Press TRIGGER to reset timer. Leave ignition on. Perform drive mode test.

EGR Monitor Repair Verification Drive Cycle

Connect scan tool. Warm engine until ECT PID is at least 163°F (73°C). Turn all accessories off. Drive vehicle at more than 48 MPH for at least 2 minutes. Stop vehicle and allow to idle for 20 seconds. Using scan tool, check drive mode completion status. If test is not complete, turn ignition off. Repeat test. If test is complete, check test results. If results are okay, ensure no DTCs are present. If results are not okay, repairs are not complete.

HO2S/TWC Monitor Repair Verification Drive Cycle

Ensure vehicle engine coolant (ECT) PID is less than 170°F (76°C) and fuel level (FLI) PID is at least 15 percent. monitor period will start 5 minutes after engine is started. Connect scan tool. Warm engine to operating temperature 175-240°F (80-115°C). Drive vehicle at a steady speed above 30 MPH for at least 2 minutes. Stop vehicle. Using scan tool, check drive mode completion status. If test is not complete, turn ignition off. Repeat test from point after warm up. If test is complete, check test results. If results are okay, ensure no DTCs are present. If results are not okay, repairs are not complete.

EVAP Monitor Repair Verification Drive Cycle

Note. 8 hour timer may be shortened by 3 hours depending on conditions. If soak period is shortened, PCM may detect a malfunction even after repairs. This may happen under warm or hot conditions.

Ensure vehicle inlet air temperature (IAT) PID is 14-102°F (-10-38°C) and fuel level (FLI) PID is 15-85 percent. monitor period will be during 4-10 minutes after engine is started. System test takes at least 30 seconds during this time. If time exceeds 10 minutes, turn ignition off and restart test. Cold soak vehicle for 8 hours. Connect scan tool. Turn all accessories off. Start engine. Accelerate to 35-65 MPH within 4 minutes. Drive vehicle at 35-65 MPH for at least 2 minutes. Stop vehicle and allow to idle for 20 seconds. Using scan tool, check drive mode completion status. If test is not complete, repeat test from engine start. If test is complete, check test results. If results are okay, ensure no DTCs are present. If results are not okay, repairs are not complete.

To bypass 8 hour timer, cool fuel tank as much as possible. Connect scan tool. Access CLEAR DIAGNOSTIC CODES. Press TRIGGER to reset timer. Leave ignition on. Perform drive mode test.

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.

Condition

DTC P0102 indicates MAF signal was less than 0.39 volt sometime during normal engine operation. Possible causes for this fault are

  1. Open MAF circuit.
  2. Open circuit (MAF, MAF RTN, PWR GND, or VPWR).
  3. MAF circuit shorted to ground.
  4. Air leak before or after MAF sensor.
  5. Faulty MAF sensor or connector.
  6. Faulty TP system (2.5L).
  7. Faulty PCM.
  1. Check MAF Low Input Signal To PCM Ensure freeze frame data is recorded. Ensure air induction system is okay. Repair if necessary. Start engine and allow to idle. If engine does not idle smoothly, repair cause of rough idle condition before continuing. If DTC P0505 is present, see appropriate test and repair first. With scan tool connected, increase engine speed to 1500 RPM and return to idle. Using scan tool, access MAF PID. If MAF PID is 0.6-1.0 volt, go to step 10 . For all other MAF PID readings, go to next step.
  2. Check VPWR Circuit Voltage Turn ignition off. Disconnect MAF sensor and inspect for damage. Repair as necessary. Turn ignition on. Measure voltage between VPWR terminal on MAF sensor wiring harness connector and negative battery terminal. If voltage is 10.5 volts or more, go to next step. If voltage is less than 10.5 volts, repair open in VPWR circuit.
  3. Check Resistance Of VPWR Circuit Turn ignition off. Leave MAF sensor disconnected. Disconnect PCM 104-pin connector and inspect for damage. Repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between VPWR terminal on MAF sensor wiring harness connector and test pins No. 71 or 97 (VPWR) at breakout box. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in VPWR circuit and repeat QUICK TEST.
  4. Check MAF Circuit For Short To Ground & MAF RTN Circuit Leave ignition off and MAF disconnected. Ensure PCM is disconnected. Disconnect scan tool from DLC (if applicable). Measure resistance between test pin No. 88 (MAF SIG) and test pins No. 36 (MAF RTN), 24 and 103 (PWR GND) at breakout box. If resistance is 10 k/ohms or more, reconnect scan tool and go to next step. If resistance is less than 10 k/ohms, repair circuit short to ground and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  5. Check Resistance Of MAF SIG Circuit Leave ignition off, PCM and MAF disconnected. Measure resistance between MAF terminal on MAF sensor wiring harness connector and test pin No. 88 (MAF SIG) at breakout box. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open circuit in MAF SIG circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  6. Check PWR GND Circuit To MAF Sensor Leave ignition off and MAF disconnected. Connect PCM to breakout box. Turn ignition on. Measure voltage between VPWR and PWR GND terminal on MAF sensor wiring harness connector. If voltage is less than 10.5 volts, go to next step. If voltage is 10.5 volts or more, go to step 13 .
  7. Check PWR GND Circuit Resistance Leave ignition off and MAF sensor disconnected. Disconnect PCM from breakout box. Disconnect scan tool from DLC (if applicable). Measure resistance between PWR GND terminal on MAF sensor wiring harness connector and negative battery terminal. If resistance is less than 10 ohms, go to next step. If resistance is 10 ohms or more, repair open in PWR GND circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  8. Check MAF RTN Circuit Resistance Leave ignition off, and PCM and MAF sensor disconnected. Measure resistance between MAF RTN terminal on MAF sensor wiring harness connector and test pin No. 36 (MAF RTN) at breakout box. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in MAF RTN and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  9. Check MAF Circuit For Short To Ground In PCM Leave ignition off and MAF disconnected. Connect PCM to breakout box. Disconnect scan tool from DLC (if applicable). Measure resistance between test pin No. 88 (MAF SIG) and test pins No. 36 (MAF RTN), 24 and 103 (PWR GND) at breakout box. If resistance is 10 k/ohms or more, go to next step. If resistance is less than 10 k/ohms, replace PCM and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  10. Check MAF Circuit Output Ensure ignition is off. Reconnect MAF sensor. Connect PCM to breakout box. Start engine and allow to idle. If engine does not idle smoothly, repair cause of rough idle condition before continuing. Measure voltage between test pin No. 88 (MAF SIG) and negative battery cable. If voltage is 0.34-1.96 volts, go to next step. If voltage is not 0.34-1.96 volts, replace MAF sensor and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  11. Verify MAF Circuit Input And Output Ensure ignition is off, and MAF sensor and PCM are connected. With engine idling, measure voltage between test pins No. 36 (MAF RTN) and 88 (MAF SIG). If voltage is 0.34-1.96 volts, go to next step. If voltage is not 0.34-1.96 volts, replace MAF sensor and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  12. Check MAF Circuit Output With Scan Tool Start engine and allow to idle. Access MAF PID on scan tool. If PID voltage is 0.34-1.96 volts, fault is intermittent and cannot be identified at this time. Ensure all applicable connections are clean and tight, and go to DIAGNOSTIC TEST Z (INTERMITTENT). If voltage is not 0.34-1.96 volts, replace PCM and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  13. Check MAF Sensor Output Voltage Turn ignition off. Ensure MAF sensor is connected. Disconnect PCM 104-pin connector and inspect for damage. Repair as necessary. Install Breakout Box (014-00950). Leave PCM connected to breakout box. With scan tool connected, turn ignition on. Measure voltage between test pin No. 88 (MAF SIG) and test pins No. 24 and 103 (PWR GND). If voltage is greater than 0.2 volt, go to step 7 . If voltage is 0.2 volt or less, go to step 3 .

DTC P0103 indicates MAF signal was greater than 4.35 volts sometime during normal engine operation. Possible causes for this fault are as follows

  1. Restricted MAF sensor screen.
  2. MAF SIG circuit shorted to VPWR.
  3. Faulty MAF sensor or connector.
  4. Faulty PCM.
  1. Check MAF Signal High Input To PCM Ensure freeze frame data is recorded. Ensure air induction system is okay. Repair if necessary. Start engine and allow to idle. If engine does not idle smoothly, repair cause of rough idle condition before continuing. If DTC P0505 is present, see appropriate test and repair first. With scan tool connected, increase engine speed to 1500 RPM and return to idle. Access MAF PID. If PID reading is greater than 4.9 volts, go to next step. If PID reading is 4.9 volts or less, go to step 4 .
  2. Check MAF SIG Circuit For Short To Power Turn ignition off. Disconnect MAF sensor. Start engine and allow to idle. Using scan tool, access MAF PID. If PID voltage reading does not drop to less than 1.0 volt, repair wiring and go to next step. If PID voltage reading does drop to less than 1.0 volt, replace MAF sensor and go to next step.
  3. Erase DTC Clear DTCs. Check for DTCs. If DTC P0103 returns, replace PCM and retest. If DTC P0103 does not return, go to next step.
  4. Erase DTC If any DTCs are present, go to appropriate test. If no DTCs are present, test is complete.

This DTC indicates EGR boost sensor input signal is out of self-range. Possible causes for this fault are

  1. Faulty EGR boost sensor.
  2. Faulty EGR boost solenoid valve.
  3. Faulty EGR solenoid valve-to-EGR boost sensor hose.
  4. Faulty PCM.
  5. Open or short in wiring.
  1. Check EGR Boost Sensor Constant Voltage Ensure freeze frame data is recorded. Turn ignition off. If DTC P1410 is present, see appropriate test and repair first. Disconnect EGR boost sensor. Check vacuum hose and connector. Turn ignition on. Measure voltage between SIG RTN terminal and VREF terminal at EGR boost sensor wiring harness connector. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, repair open VREF circuit. NOTE: If DTC P1410 is present, ensure fuel pressure regulator control solenoid and EGR boost solenoid valve wiring harness connectors are not crossed.
  2. Check EGR Boost Circuit Resistance Leave EGR boost sensor disconnected. Turn ignition off. Disconnect PCM 104-pin connector. Inspect for damaged pins and repair if necessary. Connect Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pin No. 34 and EGR boost terminal at EGR boost sensor wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  3. Check EGR Boost Circuits For Short To Ground Or Power Leave ignition off and EGR boost sensor disconnected. Measure resistance between test pin No. 34 (EGR boost) and test pins No. 91 (SIG RTN), No. 51 and No. 103 (PWR GND) at breakout box. Measure resistance between test pin No. 34 and test pins No. 71 (VPWR), No. 90 (VREF), and No. 97 (VPWR) at breakout box. If each measurement is 10 k/ohms or more, go to next step. If any measurement is less than 10 k/ohms, repair short circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  4. Check Vacuum Lines Check all vacuum hoses connected to the EGR check solenoid. Repair or replace as necessary and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  5. Check EGR Boost Sensor Response Leave ignition off. Disconnect vacuum hose between EGR boost sensor and EGR boost solenoid. Inspect hose for damage and repair if necessary. Connect vacuum pump to EGR boost sensor vacuum port. Turn ignition on. While measuring voltage between test pins No. 34 (EGR boost) and No. 51 (PWR GND), slowly apply 21 in. Hg. If voltage response is 0.8-1.5 volts, go to next step. If voltage is not as specified, replace EGR boost sensor and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  6. Check VPWR At EGR Boost Solenoid Turn ignition off. Disconnect EGR boost solenoid. Start engine and allow to idle. Measure voltage between VPWR terminal on EGR boost solenoid wiring harness connector and chassis ground. If voltage is 10.5 volts or more, go to next step. If voltage is less than 10.5 volts, repair open VPWR circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  7. Check EGR Boost Solenoid Resistance Turn ignition off. Disconnect EGR boost solenoid wiring harness connector. Measure resistance between solenoid terminals. If resistance is 30-70 ohms, go to next step. If resistance is not 30-70 ohms, replace EGR control solenoid. Clear PCM memory and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  8. Check EGR Boost Solenoid Circuit Resistance Leave ignition off and EGR boost solenoid disconnected. Measure resistance between test pin No. 98 and EGR boost solenoid terminal on solenoid harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in EGR boost solenoid circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  9. Check EGR Boost Solenoid Circuits For Short To Ground Or Power Leave ignition off and EGR boost solenoid disconnected. Disconnect scan tool from DLC (if applicable). Measure and record resistance between test pin No. 98 and test pins No. 91 (SIGRTN), 51 and No. 103 (PWR GND) at breakout box. Measure and record resistance between test pin No. 98 and test pins No. 71 (VPWR), No. 90 (VREF), and No. 97 (VPWR) at breakout box. If each measurement is 10 k/ohms or more, go to next step. If any measurement is less than 10 k/ohms, repair short in EGR boost circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  10. Check EGR Boost Solenoid Response Leave ignition off. Disconnect vacuum hose to EGR boost solenoid. Inspect hose for damage and repair if necessary. Connect vacuum pump to EGR boost solenoid vacuum port and apply 10 in. Hg. Turn ignition on. Momentarily jumper test pin No. 98 at breakout box to ground. If vacuum signal of 8-10 in. Hg is indicated by vacuum gauge, EGR boost solenoid is okay. Replace PCM and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If vacuum signal of 8-10 in. Hg is not indicated by vacuum gauge, replace EGR boost solenoid and repeat QUICK TEST.

This DTC indicates EGR boost pressure sensor circuit input signal is less than the self-test minimum. Possible causes for this fault are

  1. Faulty EGR boost sensor.
  2. Faulty EGR boost solenoid valve.
  3. Faulty EGR solenoid valve-to-EGR boost sensor hose.
  4. Faulty PCM.
  1. Check EGR Boost Sensor VREF Voltage Ensure freeze frame data is recorded. Turn ignition off. Disconnect EGR boost sensor. Turn ignition on. Measure voltage between SIG RTN terminal and VREF terminal at EGR boost sensor wiring harness connector. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, repair open VREF circuit.
  2. Check EGR Boost Circuit Resistance Leave EGR boost sensor disconnected. Turn ignition off. Disconnect PCM 104-pin connector. Inspect for damaged pins and repair if necessary. Connect Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pin No. 34 (EGR Boost) and EGR boost terminal at EGR boost sensor wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in EGR boost circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  3. Check EGR Boost Circuit For Short To Ground Leave ignition off and EGR boost sensor disconnected. Measure resistance between test pin No. 34 (EGR Boost) and test pins No. 91 (SIG RTN), 51 and No. 103 (PWR GND) at breakout box. If each measurement is 10 k/ohms or more, go to next step. If any measurement is less than 10 k/ohms, repair short in EGR boost circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  4. Check EGR Boost Sensor Response Leave ignition off. Disconnect vacuum hose between EGR boost sensor and EGR boost solenoid. Inspect hose for damage and repair if necessary. Connect vacuum pump to EGR boost sensor vacuum port. Turn ignition on. While measuring voltage between test pins No. 34 (EGR boost) and No. 51 (PWR GND), slowly apply 21 in. Hg. If voltage response is 0.8-1.5 volts, go to next step. If voltage is not as specified, replace EGR boost sensor and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .

This DTC indicates EGR Barometric pressure sensor EGR boost sensor input signal is out of self-test range. Possible causes for this fault are

  1. Faulty EGR boost sensor.
  2. Faulty EGR boost solenoid valve.
  3. Faulty EGR solenoid valve-to-EGR boost sensor hose.
  4. Faulty PCM.
  1. Check EGR Boost Sensor VREF Voltage Ensure freeze frame data is recorded. Turn ignition off. Disconnect EGR boost sensor. Turn ignition on. Measure voltage between SIG RTN terminal and VREF terminal at EGR boost sensor wiring harness connector. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, repair open VREF circuit.
  2. Check EGR Boost Circuit Resistance Leave EGR boost sensor disconnected. Turn ignition off. Disconnect PCM 104-pin connector. Inspect for damaged pins and repair if necessary. Connect Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pin No. 91 (SIG RTN) and SIR RTN terminal at EGR boost sensor wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in SIG RTN circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  3. Check EGR Boost Circuit For Short To Ground Or Power Leave ignition off and EGR boost sensor disconnected. Measure resistance between test pin No. 34 and test pins No. 71 (VPWR), 90 (VREF), and 97 (VPWR) at breakout box. If each resistance measurement is 10 k/ohms or more, go to next step. If any measurement is less than 10 k/ohms, repair short in EGR boost circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  4. Check EGR Boost Sensor Response Leave ignition off. Disconnect vacuum hose between EGR boost sensor and EGR boost solenoid. Inspect hose for damage and repair if necessary. Connect vacuum pump to EGR boost sensor vacuum port. Turn ignition on. While measuring voltage between test pins No. 34 (EGR boost) and No. 51 (PWR GND), slowly apply 21 in. Hg. If voltage response is 0.8-1.5 volts, perform repairs as necessary. If voltage is not as specified, replace EGR boost sensor and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .

This DTC indicates sensor signal is less than self-test minimum. Minimum signal for IAT and ECT sensor is 0.2 volt. Possible causes for this fault are

  1. Circuit grounded in wiring harness.
  2. Faulty sensor.
  3. Faulty connection.
  4. Faulty PCM.
  1. Simulate Opposite Signal To PCM Ensure freeze frame data is recorded. Turn ignition off. Disconnect wiring harness connector from suspect sensor. Check for damaged wiring, and repair as necessary. With scan tool connected, turn ignition on. Using scan tool, access ECT V or IAT V PID. If PID is less than 4.2 volts, go to next step. If PID is 4.2 volts or more, replace sensor and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  2. Check VREF Circuit Voltage At TP Sensor Turn ignition off. Disconnect TP sensor wiring harness connector. Turn ignition on. Measure voltage between VREF and SIG RTN at TP sensor wiring harness connector. If voltage is 4-6 volts, connect TP sensor and go to next step. If voltage is not 4-6 volts, repair open in VREF circuit.
  3. Check Signal Circuit For Short To Ground Turn ignition off. Disconnect suspect sensor. Disconnect PCM 104-pin connector. Check for damaged wiring, and repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pin No. 7 (ECT) or 25 (IAT) and test pins No. 40, 46 and 60. If any reading is less than 10 k/ohms, repair short circuit, and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If all readings are 10 k/ohms or more, replace PCM and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .

These trouble codes indicate possible intermittent fault. Possible causes for this fault are

  1. Faulty sensor.
  2. Faulty sensor connector.
  3. Open or grounded circuit in harness.
  4. Faulty PCM.
  1. Check Sensor Ensure freeze frame data is recorded. With scan tool connected, turn ignition on. Access ECT or IAT PID. While observing PID, tap on sensor to simulate road shock. Wiggle sensor connector. If no change in temperature reading occurs, go to next step. If any change in temperature occurs, isolate fault and repair as necessary.
  2. Check Wiring Harness While in PID, wiggle and bend small sections of wiring harness working toward PCM. If fault is indicated, isolate fault and repair as necessary. Clear memory, and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If no fault is found, go to next step.
  3. Inspect PCM & Wiring Harness Connectors Turn ignition off. Disconnect PCM 104-pin connector. Inspect connector for damaged pins, corrosion and loose wires. If connectors and terminals are damaged, repair as necessary and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If connectors and terminals are okay, fault cannot be duplicated at this time and testing is complete.

This code indicates TP signal is less than self-test minimum of 0.17 volt. Possible causes for this fault are

  1. TP sensor not seated correctly.
  2. Faulty TP sensor.
  3. Open TP or VREF circuit.
  4. TP circuit shorted to SIG RTN or PWR GND.
  5. Faulty PCM.
  1. Attempt To Generate DTC P0123 Ensure freeze frame data is recorded. Turn ignition off. Disconnect TP sensor wiring harness connector. Inspect for damage and repair as necessary. Connect jumper wire between VREF and TP terminal at TP wiring harness connector. Turn ignition on. Access TP PID on scan tool. If PID voltage is greater than 4.60 volts, replace TP sensor and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If PID voltage is 4.60 volts or less, remove jumper wire and go to next step. If scan tool is unable to access TP PID, go to step 4 .
  2. Check VREF Circuit Voltage With TP sensor disconnected, turn ignition on. Measure voltage between VREF and SIG RTN terminals at TP sensor wiring harness connector. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, reconnect sensor and repair open VREF circuit.
  3. Check TP Circuit Resistance Turn ignition off. Leave TP sensor disconnected. Disconnect PCM 104-pin connector. Inspect connector for damage and repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pin No. 89 (TP) and TP terminal on TP sensor wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in TP circuit.
  4. Check TP Circuit For Short To SIG RTN Or PWR GND Leave ignition off and TP sensor disconnected. Measure resistance between test pin No. 89 (TP) and test pins No. 91 (SIG RTN), 24 and 103 (PWR GND) at breakout box. If any resistance is less than 10 k/ohms, repair TP circuit short to SIG RTN or PWR GND and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If both resistances are 10 k/ohms or more, replace PCM and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .

This code indicates TP signal is greater than self-test maximum of 4.79 volt. Possible causes for this fault are

  1. TP sensor not seated correctly.
  2. Faulty TP sensor.
  3. Open TP or VREF circuit.
  4. TP circuit shorted to SIG RTN or PWR GND.
  5. Faulty PCM.
  1. Attempt To Generate DTC P0122 Ensure freeze frame data is recorded. Turn ignition off. Disconnect TP sensor wiring harness connector. Inspect for damage and repair as necessary. Turn ignition on. Using scan tool, access TP PID on scan tool. If TP PID voltage is 0.17 volt or more, go to step 3 . If TP PID voltage is less than 0.17 volt, go to next step.
  2. Check VREF Circuit Voltage With TP sensor disconnected, turn ignition on. Measure voltage between VREF and SIG RTN terminals at TP sensor wiring harness connector. If reading is 4-6 volts, go to next step. If reading is not 4-6 volts, reconnect sensor and repair open VREF circuit.
  3. Check TP Circuit For Short To Power Turn ignition off. Leave TP sensor disconnected. Disconnect PCM 104-pin connector. Inspect connector for damage and repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pin No. 89 (TP) and test pins No. 71, 90 and 97 (VPWR) at breakout box. If any resistance is less than 10 k/ohms, repair TP circuit short to VREF and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If each resistance is 10 k/ohms or more, replace PCM and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .

DTC is set when engine coolant temperature has not increased after engine is started and default period of time has passed. Possible causes for this fault are

  1. Insufficient engine warm-up time.
  2. Thermostat leaking or stuck open.
  3. Low coolant.

Repair cooling system as necessary. Clear PCM memory, and repeat QUICK TEST .

This code indicates response rate is below calibration in HO2S. Possible causes are as follows

  1. Open or shorted circuit.
  2. Exhaust leak.
  3. Excessive fueling.
  4. HO2S coated with contaminants.
  5. Faulty MAF sensor.
  6. Leak in air induction system.
  1. Perform KOER Self-Test Ensure freeze frame data is recorded. If DTC P1127 is present, service before proceeding. If DTC P1127 is not present, go to next step.
  2. HO2S Response Test With scan tool connected, turn ignition on. Using scan tool, access Generic OBD-II functions and enter. Select DIAGNOSTIC MONITORING TEST RESULTS and enter. Scroll to TEST ID: 01 and enter. Press START. If measured value is 614 or more, fault cannot be duplicated or identified at this time and testing is complete. If measurement fault is less than 614, go to next step.
  3. Check For HO2S Contamination Check following possibilities as potential source of contamination: Use of unapproved silicon sealers. Use of unapproved cleaners. Fuel contaminated by silicon additives. Fuel contaminated by lead. Excessive oil burning. Antifreeze leaking internally. If any of these conditions are present, repair or replace as necessary. Replace HO2S. Change oil, filter and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If none of these conditions are present, go to next step.
  4. Check For Unmetered Air Leaks Vacuum or air leaks in non-EEC-V areas could cause fault code to set. Check the following as potential source of air leak: Leaking vacuum hoses. Leaking intake manifold gasket. EGR system. PCV system. Poorly seated oil dip stick and/or dipstick tube. If any of these conditions are present, repair or replace as necessary. Perform drive cycle and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If none of these conditions are present, go to next step. NOTE: On 2.0L models, front HO2S is identified on scan tool as O2S11, rear HO2S is O2S12. On 2.5L models, right front HO2S is identified on scan tool as O2S11, middle HO2S is O2S12, left front HO2S is O2S21 and rear HO2S is O2S13.
  5. Check HO2S Circuits Turn ignition off. Disconnect PCM and suspect HO2S wiring harness connector. Inspect connectors for damage and repair as necessary. Connect jumper wire between HO2S SIG and VPWR at sensor wiring harness connector. With scan tool connected to DLC, turn ignition on. Access HO2S PID. If PID voltage is less than 1.5 volts, go to next step. If PID voltage is 1.5 volts or more, replace HO2S and change engine oil. Test drive vehicle and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  6. Check HO2S Signal Circuit Resistance Turn ignition off. Disconnect PCM 104-pin connector. Inspect connector for damage and repair if necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between suspect HO2S test pin at breakout box and HO2S terminal at wiring harness connector. Measure resistance between SIG RTN test pin No. 60 and/or 87 (2.5L) at breakout box and SIG RTN terminal at wiring harness connector. If either resistance is 5 ohms or more, repair open circuit. Drive vehicle at 55 MPH for 5 minutes and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If each resistance is less than 5 ohms, go to next step.
  7. Check HO2S For Short Circuit Ensure ignition is off and PCM is disconnected. Disconnect scan tool from DLC. Measure resistance between HO2S test pin No. 60 and/or 87 (2.5L), and test pins No. 71 and 97 (VPWR) at breakout box. Measure resistance between suspect HO2S test pin and test pin No. 91 (SIG RTN) at breakout box. If either resistance is less than 10 k/ohms, repair short circuit. Drive vehicle for 5 miles at 55 MPH and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If each resistance is 10 k/ohms or more, replace PCM.

DTC indicates a short to ground or open in HO2S heater circuit. Possible causes are as follows

  1. Signal shorted in wiring harness or HO2S.
  2. Water in connectors.
  3. Cut or stretched wires.
  4. Open in PWR GND or VPWR circuit.
  1. Check HO2S Heater Signal Circuit Ensure freeze frame data is recorded. Inspect HO2S connectors for damage or poor connection. Repair or replace connectors as necessary. If HO2S connectors are okay, go to next step.
  2. Perform KOEO Self-Test Start engine and operate at 2000 RPM for 5 minutes. Turn ignition off. Perform KOEO self-test. If DTC P0135, P0141, P0147 or P0155 is present, go to next step. If DTCs are not present, ensure all applicable connections are clean and tight, and go to «DIAGNOSTIC TEST Z (INTERMITTENT)»(ref-91102-S20258564262001030200000) .
  3. Check For Voltage At HO2S Heater Wiring Harness Connector Turn ignition off. Disconnect suspect HO2S. Inspect wiring harness for damage and repair as necessary. Turn ignition on. Measure voltage between SIG RTN and VPWR terminal at HO2S wiring harness connector. If voltage is 10.5 volts or less, go to next step. If voltage is greater than 10.5 volts, go to step 5 .
  4. Check For Open VPWR Circuit Turn ignition off. With suspect sensor disconnected, measure resistance between VPWR terminal at HO2S wiring harness connector and test pins No. 71 and 97 at breakout box. If resistance is less than 4 ohms, go to next step. If resistance is 4 ohms or more, check circuit fuse. If fuse is okay, repair open circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  5. Check HO2S Heater Resistance Turn ignition off. With suspect sensor disconnected, measure resistance between HO2S HEATER GND terminal and VPWR terminal at HO2S wiring harness connector. If resistance is 3-30 ohms, go to next step. If resistance is not 3-30 ohms, replace HO2S sensor and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  6. Check For Short To HO2S Case Leave ignition off and suspect sensor disconnected. Measure resistance between HO2S HEATER GND terminal at HO2S wiring harness connector and HO2S case. Measure resistance between HO2S HEATER GND terminal and SIG RTN terminal at HO2S wiring harness connector. Measure resistance between VPWR terminal at HO2S wiring harness connector and HO2S case. If each resistance measurement is greater than 10 k/ohms, go to next step. If any resistance is 10 k/ohms or less, replace HO2S and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  7. Check For Short Circuit Leave ignition off and sensor disconnected. Disconnect scan tool from DLC (if applicable). Disconnect PCM 104-pin connector. Inspect connector for damage and repair if necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between suspect sensor and test pins indicated as follows: DTC P0135, test pin No. 93 and test pins No. 24, 76, 91, 97 and 103. DTC P0141, test pin No. 95 and test pins No. 24, 76, 91, 97 and 103. DTC P0147, test pin No. 96 and test pins No. 24, 76, 91, 97 and 103. DTC P0155, test pin No. 94 and test pins No. 24, 76, 91, 97 and 103. If resistance is greater than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short in circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  8. Check For Open HO2S Heater Ground Harness Circuit Leave ignition off and sensor disconnected. Measure resistance between HO2S HEATER GND terminal at HO2S wiring harness connector and appropriate test pin. See «HO2S GROUND TERMINAL IDENTIFICATION»(ref-91102-S28024450902001030200000) table. If resistance is 4 ohms or more, repair open circuit or excessive resistance in wiring harness and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If resistance is less than 4 ohms, replace PCM and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
ApplicationTest Pin No.
2.0L
Front HO2S93
Rear HO2S95
2.5L
Right Front HO2S93
Left Front HO2S94
Middle HO2S95
Rear HO2S96

HO2S GROUND TERMINAL IDENTIFICATION

Fuel pump primary circuit has been indicated. Possible causes are as follows

  1. Open or shorted circuit.
  2. Faulty fuel pump relay.
  3. Faulty PCM.
  1. KOEO & KOER DTC P0230 Ensure freeze frame data is recorded. Disconnect fuel pump relay wiring harness connector. Turn ignition on. Measure voltage between VPWR terminal at connector and chassis ground. If 10.5 volts or more are present, go to next step. If less than 10.5 volts are present, repair open in VPWR circuit between EEC power relay and fuel pump relay. NOTE: To Identify fuel pump relay terminals, refer to numbers molded on relay.
  2. Check Fuel Pump Relay Turn ignition off. Leave fuel pump relay disconnected. Measure resistance between terminals No. 1 or No. 85 and all other terminals. Resistance should be either 40-120 ohms, or greater than 10 k/ohms. Replace fuel pump relay if resistance is not as specified. If resistance is okay, go to next step.
  3. Check Fuel Pump Circuit Leave ignition off and fuel pump relay disconnected. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Turn ignition on. On models equipped with immobilizer system, measure voltage between test pin No. 70 and chassis ground. On models not equipped with immobilizer system, measure voltage between test pin No. 80 and chassis ground. On all models, if voltage is one volt or less, go to next step. If voltage is greater than one volt, repair short to power in fuel pump circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  4. Check Fuel Pump Circuit For Short To Ground Leave ignition off and fuel pump relay disconnected. Disconnect scan tool from Data Link Connector (DLC). On models equipped with immobilizer system, measure voltage between test pin No. 70 and test pins No. 51, 91 and 103. On models not equipped with immobilizer system, measure voltage between test pin No. 80 and test pins No. 51, 91 and 103. If each resistance measurement is greater than 10 k/ohms, go to next step. If any resistance measurement is 10 k/ohms or less, repair short circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  5. Check Fuel Pump Circuit Continuity Leave ignition off and fuel pump relay disconnected. Measure resistance between FUEL PUMP terminal at fuel pump relay wiring harness connector and test pin No. 70 (with immobilizer unit) or No. 80 (without immobilizer unit) at breakout box. If resistance is less than 5 ohms, replace PCM and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If resistance is 5 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .

DTC is set when Fuel Tank Pressure (FTP) sensor input voltage is less than minimum. Possible causes are

  1. FTP sensor completely submerged in liquid fuel.
  2. FTP sensor connector contamination.
  3. Ground short circuit.
  4. Damaged FTP sensor.
  5. Faulty PCM.
  1. Inspect FTP Sensor Ensure freeze frame data is recorded. Determine if fuel tank is overfilled, causing FTP sensor harness connector to be contaminated with liquid fuel. Correct as needed and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If FTP sensor harness connector is not contaminated with liquid fuel, go to next step.
  2. Check FTP Sensor Turn ignition on. Using scan tool, access FTP V PID. If FTP V PID is less than .22 volt, go to next step. If FTP V PID is .22 volt or greater, fault is intermittent. Go to «DIAGNOSTIC TEST Z (INTERMITTENT)»(ref-91102-S20258564262001030200000) .
  3. Induce Opposite FTP Signal Turn ignition off. Connect a jumper wire between SIG RTN and FTP terminals at FTP sensor wiring harness connector. Turn ignition on. Using scan tool, select FTP V PID. If PID voltage is 4-6 volts, replace FTP sensor and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If PID voltage is not 4-6 volts, remove jumper wire and go to next step.
  4. Check VREF Voltage At FTP Sensor Connector Turn ignition off. Ensure FTP sensor harness connector is disconnected. Turn ignition on. Measure voltage between VREF and SIG RTN terminals on FTP harness connector. Using scan tool, select FTP V PID. If PID voltage is 4-6 volts, go to next step. If PID voltage is not 4-6 volts, voltage is out of range. Repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  5. Check FTP Signal Circuit For Short To Ground Turn ignition off. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Ensure FTP harness connector is disconnected. Measure resistance between test pin No. 62 and test pins No. 51, 91 and 103. If resistance for each circuit is greater than 10 k/ohms, replace PCM and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If resistance for each circuit is 10 k/ohms or less, inspect each circuit for short to ground. Repair as needed. Repeat QUICK TEST.
  6. Evaporative System Recheck Erase DTCs. Perform appropriate drive cycle under «QUICK TEST»(ref-91102-S14663847332001030200000) . If MIL is illuminated, EVAP system has leak. Inspect and repair as needed. Repeat this step. If MIL is not illuminated, fault is not currently present.

DTC is set when Fuel Tank Pressure (FTP) sensor input voltage is greater than maximum. Possible causes are

  1. FTP SIG RTN short circuit.
  2. Sensor ground circuit open.
  3. Damaged FTP sensor.
  4. Faulty PCM.
  1. Verify DTC P0453: Check FTP Sensor Voltage Ensure freeze frame data is recorded. Check FTP sensor. See SYSTEM & COMPONENT TESTING - EXCEPT B2500, B3000 & B4000 article. Check connectors. Repair as necessary. Turn ignition on. Using scan tool, select FTP V PID. If PID voltage is greater than 4.5 volts, go to next step. If voltage is 4.5 volts or less, fault is intermittent. Go to «DIAGNOSTIC TEST Z (INTERMITTENT)»(ref-91102-S20258564262001030200000) .
  2. Check For Short To Power Turn ignition off. Disconnect FTP sensor connector, located on top of fuel tank. Turn ignition on. Measure voltage between FTP terminal at FTP sensor wiring harness connector and negative battery terminal. If voltage is 10.5 volts or less, go to step 4 . If voltage is greater than 10.5 volts, go to next step.
  3. Check FTP Circuit For Short To VPWR Circuit Turn ignition off. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Install Breakout Box (014-00950), leaving PCM disconnected. Turn ignition on. Measure voltage between test pin No. 62 and test pins No. 51 and 103 at breakout box. If voltage is greater than 10.5 volts, repair short circuit. If voltage is 10.5 volts or less, replace PCM.
  4. Check Opposite Induced Low FTP Signal Turn ignition off. Connect a jumper wire between SIG RTN and FTP terminals at FTP sensor harness connector. Turn ignition on. Using scan tool, select FTP V PID. If PID voltage is less than .1 volt, remove jumper wire and go to next step. If PID voltage is .1 volt or more, unable to induce opposite signal. Go to step 6 .
  5. Check Voltage At FTP Sensor Connector Measure voltage between VREF and SIG RTN terminals at FTP sensor wiring harness connector. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, VREF voltage is out of range. Inspect VREF circuit for short. Repair as needed. Repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  6. Check For Short Circuit Turn ignition off. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pins No. 62 and 90 at breakout box. If resistance is greater than 10 k/ohms, replace FTP sensor. If resistance is 10 k/ohms or less, repair FTP circuit short to VREF circuit.
  7. Evaporative System Recheck Erase DTCs. Perform appropriate drive cycle procedure under «DRIVE CYCLES»(ref-91102-S24383971062001030200000) under ADDITION SYSTEM FUNCTIONS. If MIL is illuminated, EVAP system has leak. Inspect and repair as needed. Repeat this step. If MIL is not illuminated, fault is not currently present.

DTC indicates fuel level input circuit malfunction due to low or high fuel level input to PCM, or mechanically stuck fuel pump. Possible causes are

  1. Empty fuel tank.
  2. Overfilled fuel tank.
  3. Faulty fuel pump.
  4. Faulty fuel gauge or instrument cluster.
  5. FLI circuit fault.
  6. CASE GND circuit shorted to VPWR.
  7. Faulty PCM.
  1. Verify Fuel Tank Level Ensure freeze frame data is recorded. Turn ignition on. Note fuel gauge reading. Using scan tool, select FLI PID. If both fuel gauge and FLI PID readings are between 1/4 (25 percent for FLI PID) and 3/4 (75 percent for FLI PID), go to next step. If readings are not as specified, inspect fuel tank for leaks. Repair as necessary and retest. If fuel tank is okay, go to next step.
  2. Check FLI Voltage Using Breakout Box Turn ignition off. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Install Breakout Box (014-00950). Connect PCM to breakout box. Using scan tool, select FLI V PID. Note PID voltage reading. Measure voltage between test pins No. 63 and 91 at breakout box. If both voltage readings are 1.24-2.90 volts, go to next step. If voltage is not as specified, check fuel gauge for proper installation. Repair as necessary and repeat this step to verify repair. If fuel gauge installation is okay and one voltage reading is not as specified, replace PCM. If fuel gauge installation is okay and both voltage readings are not as specified, go to next step.
  3. Check Fuel Pump Resistance Disconnect fuel pump module connector. Measure resistance between CASE GND terminal and FLI terminal at fuel pump module pigtail connector. If resistance is 15-160 ohms, reconnect fuel pump module and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If resistance is not 15-160 ohms, replace fuel pump module.

DTCs indicate that when brake pedal was applied during KOER on-demand self-test, BPP signal did not cycle high and low. Possible causes for this fault are

  1. Brake pedal not applied during self-test.
  2. Brake pedal applied during entire self-test.
  3. Open or short brakelight circuit.
  4. Open or short BPP circuit.
  5. Faulty BPP switch.
  6. Faulty Powertrain Control Module (PCM).
  1. Verify Brake Pedal Was Depressed Ensure freeze frame data is recorded. If brake was not applied and released during KOER on-demand self-test, repeat test. Depress and release brake pedal only once during test. If pedal was applied and released, go to step 3 .
  2. KOEO DTC P0703 Or P1703 These DTCs indicate that BPP signal voltage was high during KOEO on-demand self-test. Possible causes for these faults are: Brake pedal applied during self-test. Open or short BPP circuit. All brakelights open. Faulty brakelight ground. Faulty BPP switch. If brake was applied during KOEO on-demand self-test, repeat test. DO NOT apply brake during self-test. If pedal was not applied, go to next step.
  3. Check Operation Of Brakelights Check operation of brakelights. If brakelights operate normally, go to next step. If brakelights do not operate properly, go to step 5 (brakelights never on) or step 7 (brakelights always on).
  4. Check For BPP PID Cycling Turn ignition on. Using scan tool, select BPP PID from PID/DATA monitor menu. While observing PID, apply and release brake several times. If PID does not cycle ON and OFF, go to step 10 . If PID cycles ON and OFF, go to «DIAGNOSTIC TEST Z (INTERMITTENT)»(ref-91102-S20258564262001030200000) , step 10 . NOTE: If BPP PID is not available, go to step 10 .
  5. Check For Power To BPP Switch Ensure related fuses and brakelight bulbs are good. Disconnect BPP switch (located on brake pedal). Measure B+ input voltage between BPP switch wiring harness connector and chassis ground. If voltage is greater than 10 volts, go to next step. If voltage is 10 volts or less, repair open in B+ circuit to BPP switch.
  6. Check BPP Switch Depress brake pedal. Measure resistance between BPP switch terminals. If resistance is 5 ohms or more, replace BPP switch. If resistance is less than 5 ohms, repair open circuit between BPP switch and brakelight ground.
  7. Verify BPP Switch Is Not Always Closed Ensure ignition is off. Disconnect BPP switch (located on brake pedal). Turn ignition on. If brakelights are still on, go to next step. If brakelights are off, verify correct installation of BPP switch. If installation is okay, replace BPP switch.
  8. Check For Short To Power In PCM Turn ignition off. Disconnect PCM 104-pin connector. Turn ignition on. Check brakelights. If brakelights are still on, go to next step. If brakelights are off, replace PCM.
  9. Check For Short To Power Turn ignition off. Ensure PCM and BPP switch are disconnected. One at a time, disconnect all modules associated with brakelight circuit. After disconnecting each module, turn ignition on and check brakelights. Turn ignition off. Repeat until each associated module has been disconnected or brakelights turn off. If brakelights are still on after disconnecting all associated modules, repair short to power in BPP circuit. If brakelights are off with associated module(s) disconnected, diagnose appropriate module and/or related system. See DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS in appropriate MODULE COMMUNICATIONS NETWORK article in ACCESSORIES & EQUIPMENT. Determine article that is associated with module that was disconnected to eliminate short to power. Repair system or replace module as necessary.
  10. Check For BPP Circuit Cycling Turn ignition off. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure voltage between test pin No. 92 and chassis ground while applying and releasing brake. If voltage cycles on and off, replace PCM. If voltage does not cycle, repair open in BPP circuit between PCM and BPP circuit connection to brakelight B+ circuit.

DTC indicates clutch switch and/or neutral switch malfunction. Possible causes are as follows

  1. Starter relay disconnected during quick test procedure.
  2. Clutch switch and/or neutral switch circuit damage.
  3. Faulty clutch switch and/or neutral switch.
  4. Faulty Powertrain Control Module (PCM).
  1. Check CPP/PNP PID Ensure freeze frame data is recorded. Turn ignition off. Connect scan tool to Data Link Connector (DLC). Ensure shift lever is in Neutral. Turn ignition on. Using scan tool, select CPP/PNP PID. While observing CPP/PNP PID, apply and release clutch pedal. If PID value does not cycle ON and OFF, go to next step. If PID value cycles ON and OFF, check PCM connector for loose, damaged or corroded terminals. Repair as necessary. If connector is okay, replace PCM.
  2. Check Clutch Switch & Neutral Switch Turn ignition off. Locate clutch switch near clutch pedal and neutral switch near transmission shift linkage. Inspect switches and brackets for damage and repair as necessary. Disconnect switch connectors. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. While depressing clutch pedal, measure resistance between clutch switch terminals. Measure resistance between neutral switch connector terminals. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, replace suspect switch.
  3. Check Clutch Switch Circuit For Open Turn ignition off. Disconnect scan tool. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pin No. 91 (SIG RTN) at breakout box and SIG RTN terminal at clutch switch wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair open in circuit.
  4. Check Clutch Switch Circuit For Short Measure resistance between chassis ground and test pin No. 64 at breakout box. Measure resistance between test pins No. 64 and 91 at breakout box. If both resistance readings are greater than 10 k/ohms, replace PCM. If any resistance reading is 10 k/ohms or less, repair short circuit.

DTC P1100, retrieved from continuous memory indicates voltage went out of range (0.39-3.90 volts) sometime during previous 40 warm-up cycles. Possible causes for this fault are

  1. Faulty MAF sensor.
  2. Faulty MAF sensor wiring harness circuit or connector.
  1. Check MAF Circuit Ensure freeze frame data is recorded. Check MAF sensor connector. Repair as necessary. Turn ignition on. Check voltage at harness connector terminal "B". If 10.5 volts or more is present, go to next step. If less than 10.5 volts is present, repair circuit. Go to step 4 .
  2. Check MAF Sensor Circuit Integrity Turn ignition off. Check continuity between harness connector terminal "E" and ground. If continuity is present, go to next step. If continuity is not present, repair circuit. Go to step 4 .
  3. Disconnect PCM 104-pin connector and inspect for damage. Repair as necessary. If no problem is found, replace MAF sensor. Go to next step.
  4. Using scan tool, reset KAM and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If voltage does not go out of normal range, fault cannot be duplicated or identified at this time. If DTC resets, replace PCM and retest.

DTC P1101, retrieved during KOER self-test, indicates MAF signal was not 0.34-1.96 volts during self-test. Possible causes for this fault are

  1. Air leak before or after MAF sensor.
  2. Faulty or contaminated MAF sensor.
  3. Faulty MAF sensor wiring harness connector.
  4. Open PWR GND or MAF RTN circuit.
  5. Faulty PCM.
  1. Check MAF Sensor Connections Ensure freeze frame data is recorded. Check MAF sensor and PCM connectors. Repair as necessary. Go to next step.
  2. MAF Output Voltage Disconnect MAF sensor. Disconnect PCM 104-pin connector. Install Breakout Box (014-00950), leaving PCM disconnected. Disconnect NGS tester. Measure resistance between test pin No. 36 and No. 90. If resistance is more than 10,000 ohms, replace MAF sensor and go to next step. If resistance is 10,000 or less, repair short circuit and go to next step.
  3. Repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If DTC P1101 is reset, replace PCM.

DTC P1120 indicates TP sensor closed throttle position is less than range (.19 volt). Possible causes for this fault are

  1. Faulty TP sensor.
  2. Faulty Powertrain Control Module (PCM).
  1. Check Freeze Frame Data Ensure freeze frame data is recorded. Go to next step.
  2. Check PID Status Turn ignition off. Connect scan tool to DLC. Access TP V PID on scan tool. If TP V PID is 0.19 volt or more, go to next step. If TP PID is below 0.19 volt, go to step 4 .
  3. Check TPS Adjustment Check TPS adjustment. See SYSTEM & COMPONENT TESTING - EXCEPT B2500, B3000 & B4000 article. Adjust as necessary and go to next step. If TP sensor cannot be adjusted properly, replace TP sensor and retest.
  4. Erase DTC From Memory Clear DTC from memory. Recheck system. If DTC P1120 is reset, replace PCM and go to next step. If DTC P1120 is not reset, go to next step.
  5. Recheck DTC If any DTCs are present, go to appropriate test for repair. If no DTCs are present, test is complete.

This code indicates TP signal is inconsistent with MAF sensor signal. Possible causes for this fault are as follows

  1. TP sensor not seated correctly.
  2. Faulty TP sensor.
  3. Air leak between MAF sensor and throttle body.

Normal range of throttle angle measurement for TP sensor is 0-85 degrees. To pass quick test procedure, range of throttle rotation (in degrees) must be within 3 percent of specification.

  1. Check Freeze Frame Data Ensure freeze frame data is recorded. Go to next step.
  2. Rationality Check Start engine. If engine starts, go to next step. If engine does not start, check for major leaks, cracks, and openings between MAF sensor and throttle body.
  3. Check Operation Of TP Sensor Turn ignition on. Connect scan tool to DLC. Access TP V PID. Move throttle from closed to fully open slowly. If TP V PID changes smoothly, go to next step. If TP V PID drops suddenly during movement, check TP sensor. See appropriate SYSTEM & COMPONENT TESTING article. Repair as necessary.
  4. Check TP Sensor High With Engine Under Load Drive vehicle while accessing TP PID and LOAD PID. If TP PID is 2.44 volts or less and LOAD PID is greater than 25 percent, go to next step. If TP PID is greater than 2.44 volts and LOAD PID is less than 25 percent, check for cracks or openings in air induction system between MAF sensor and throttle body. If air induction system is okay, replace TP sensor.
  5. Check TP Sensor Low At Idle Start engine and allow to idle. Access TP PID and LOAD PID on scan tool. If TP PID is 0.24 volt or more and LOAD PID is less than 60 percent, go to next step. If TP PID is less than 0.24 volts and LOAD PID is 60 percent or more, check TP sensor installation. Tighten as necessary and go to step 7 .
  6. Check TP Sensor Low With Engine Under Load Drive vehicle while accessing TP PID and LOAD PID. If TP PID is 0.24 volts or less and LOAD PID is greater than 60 percent, check TP sensor installation. Tighten as necessary and go to next step. If TP PID is greater than 0.24 volts and LOAD PID is less than 60 percent, fault is intermittent and cannot be located at this time. See TROUBLESHOOTING - NO CODES article.
  7. Erase DTC From Memory Clear PCM memory. Perform test drive utilizing all phases of vehicle operation. Perform «QUICK TEST»(ref-91102-S14663847332001030200000) . If sent from step 5) or 6) and DTC P1121 is still present, replace MAF sensor. If sent from step 4) and DTC P1121 is still present, replace PCM. After repair, go to next step.
  8. Recheck DTC If any DTCs are present, go to appropriate test for repair. If no DTCs are present, test is complete.

DTC P1124 indicates TP sensor adjustment may be out of self-test range. Possible causes for this fault are

  1. Faulty TP sensor.
  2. Faulty Powertrain Control Module (PCM).

Normal range of throttle angle measurement for TP sensor is 0-85 degrees. To pass quick test procedure, range of throttle rotation (in degrees) must be within 3 percent of specification.

To prevent replacement of good components, be aware, the following areas may be at fault

  1. Idle speed.
  2. Binding throttle shaft or linkage.
  3. TP sensor not seated.
  1. Adjust Throttle Position Sensor Check TP sensor adjustment. See appropriate SYSTEM & COMPONENT TESTING article. Adjust and go to next step. If sensor cannot be adjusted properly, replace TP sensor and go to next step.
  2. Erase DTC From Memory Clear PCM memory. Perform test drive utilizing all phases of vehicle operation. Perform «QUICK TEST»(ref-91102-S14663847332001030200000) . If DTC P1124 is still present, replace PCM. After repair, go to next step. If DTC P1124 is not present, go to next step.
  3. Recheck DTC If any DTCs are present, go to appropriate test for repair. If no DTCs are present, test is complete.

DTC indicates TP signal was less than 0.17 volt (9.8 percent) or greater than 4.60 volts (92.2 percent) sometime during the last 80 drive cycles. Possible causes for this fault are

  1. Faulty TP sensor wiring harness or connector.
  2. Faulty TP sensor.
  1. Continuous Memory Code P1125 Ensure freeze frame data is recorded. Ensure scan tool is connected to DLC. Start engine and allow to idle. Increase engine speed to 1500 RPM for 5 seconds and return to idle. Using scan tool, access TP PID. While observing PID, lightly tap on TP sensor to simulate road shock. Wiggle sensor connector and wiring harness. If TP PID reading stays within normal operating range (0.49-4.60 volts), go to next step. If TP PID reading goes out of range, replace TP sensor.
  2. Check Wiring Harness Between TP Sensor & PCM Turn ignition off. Disconnect PCM 104-pin connector. Inspect connector for damage and repair as necessary. Install Breakout Box (014-00950). Connect PCM to breakout box. Connect DVOM between test pins No. 89 (TP) and 91 (SIG RTN). While observing DVOM, wiggle small sections of wiring harness starting at TP sensor and going to PCM. If DVOM reading stays within normal operating range (0.49-4.60 volts), problem is intermittent and cannot be identified at this time. Ensure all applicable connections are clean and tight, and go to «DIAGNOSTIC TEST Z (INTERMITTENT)»(ref-91102-S20258564262001030200000) . If DVOM reading goes out of range, isolate fault and repair as necessary. Clear PCM memory and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .

Note. HO2S may be displayed on scan tool as 02S.

DTC P0127 indicates that HO2S heater was not on during KOER self-test and testing of HO2S did not occur. Possible cause is cool exhaust system. To prevent replacement of good components, be aware the following non-EEC areas may be cause of driveability concerns

  1. Ignition system.
  2. Faulty evaporative emission system.
  3. EGR and/or PCV system.
  4. Air intake system.
  5. Engine oil contamination.
  6. Fuel system.
  7. Exhaust system leaks or restriction.
  8. Engine cooling system.
  1. Connect scan tool to DLC. Using scan tool, access all HO2S HEATER PIDS. If all PIDs indicate ON, repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If any PIDs are off, go to next step.
  2. Turn ignition off. Disconnect suspect sensor connector. Check connector. Repair as necessary. Check sensor heater resistance. See SYSTEM & COMPONENT TESTING - EXCEPT B2500, B3000 & B4000 article. If heater is okay, go to next step. If heater is faulty, replace sensor and go to step 5 .
  3. Turn ignition on. Check voltage at harness connector terminal "C". If 10.5 volts or more is present, go to next step. If less than 10.5 volts is present, repair open circuit and go to step 5 .
  4. Turn ignition off. Check continuity between harness connector terminal "D" and negative battery terminal. If continuity is present, go to next step. If continuity is not present, repair open circuit and go to next step.
  5. Clear PCM memory. Perform test drive utilizing all phases of vehicle operation. Perform «QUICK TEST»(ref-91102-S14663847332001030200000) . If DTC P1127 is still present, replace PCM. After repair, go to next step. If DTC P1127 is not present, go to next step.
  6. If any DTCs are present, go to appropriate test for repair. If no DTCs are present, test is complete.

Open or short circuit in EGR valve is detected. Possible causes are

  1. EGR valve coil.
  2. EGR valve control signal open circuit.
  3. EGR valve control signal short circuit.
  1. Inspect Connector Condition Ensure freeze frame data is recorded. Disconnect and inspect condition of connector. Repair as needed and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If connector is okay, go to next step.
  2. Check EGR Valve VPWR Circuit Turn ignition off. Disconnect EGR valve connector. Turn ignition on. Measure voltage between VPWR terminal on EGR valve harness connector and negative battery terminal. If voltage is 10.5 volts or less, repair open VPWR circuit. If voltage is greater than 10.5 volts, go to next step.
  3. Check EGR Valve Control Signal Circuit For Short To Ground Ensure EGR valve connector is disconnected. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Measure resistance between test pins No. 46, 56, 68, 72 and negative battery terminal. If resistance is greater than 10 k/ohms for all circuits, go to next step. If resistance is 10 k/ohms or less for any circuit, inspect and repair suspect short circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  4. Check Continuity Of EGR Valve Control Circuits Ensure EGR valve and PCM connectors are disconnected. Install Breakout Box (014-00950). Measure resistance between specified breakout box test pins and EGR valve harness connector terminals. See «EGR VALVE-TO-PCM CIRCUIT IDENTIFICATION»(ref-91102-S37967445532001030200000) table. If resistance is less than 5 ohms for all circuits, replace EGR valve and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If resistance is 5 ohms or greater on any circuit, inspect and repair suspect circuit. Repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
Test Pin No.EGR Terminal
46B
56F
68E
72A

EGR VALVE-TO-PCM CIRCUIT IDENTIFICATION

Difference of EGR boost pressure and atmospheric pressure is not within specification. Possible causes are

  1. EGR boost sensor vacuum signal hose.
  2. Connecting hose.
  3. MAF sensor air leaks.
  4. EGR boost solenoid open or short circuit.
  5. EGR boost sensor.
  6. EGR boost solenoid valve.
  7. PCM malfunction.
  1. Visual Inspection Ensure freeze frame data is recorded. Ensure the following systems of components are in acceptable condition: Intake air system. PCV system. Vacuum system. Vacuum hose between EGR boost solenoid valve and intake manifold. Vacuum hose between EGR boost solenoid valve and EGR boost sensor. Repair as needed and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If any DTCs are present, repair first. If no problems are found, go to next step.
  2. Check VPWR At EGR Boost Solenoid Valve Turn ignition off. Disconnect EGR boost solenoid valve. Turn ignition on. Measure voltage between VPWR terminal of EGR boost solenoid valve harness connector and chassis ground. If voltage is 10.5 volts or more, go to next step. If voltage is less than 10.5 volts, repair open VPWR circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  3. Check EGR Boost Solenoid Valve Resistance Turn ignition off. Disconnect EGR boost solenoid valve harness connector. Measure resistance between solenoid terminals. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, replace EGR boost solenoid valve. Clear PCM memory and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  4. Check EGR Boost Solenoid Valve For Short To Power Leave ignition off and EGR boost solenoid valve harness connector disconnected. Disconnect PCM 104-pin harness connector. Inspect pins for damage and repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Turn ignition on. Measure voltage between test pin No. 98 and chassis ground. If voltage is less than one volt, go to next step. If voltage is one volt or greater, repair short to power in EGR boost solenoid valve circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  5. Check EGR Boost Solenoid Valve Circuit For Short To Ground Leave ignition off and EGR boost solenoid valve disconnected. Disconnect scan tool from DLC (if applicable). Measure resistance between test pin No. 98 and test pins No. 91 (SIG RTN), 51 and 103 (PWR GND) at breakout box. If resistance is 10 k/ohms or more, go to next step. If resistance is less than 10 k/ohms, repair short in EGR boost solenoid valve circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  6. Check EGR Boost Solenoid Valve Circuit Resistance Leave ignition off and EGR boost solenoid valve harness connector disconnected. Measure resistance between test pin No. 98 and corresponding terminal at EGR boost solenoid valve harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  7. Check EGR Boost Sensor Voltage Disconnect EGR boost sensor connector. Turn ignition on. Measure voltage between harness connector terminals. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, inspect and repair VPWR circuit. Repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  8. Check Continuity Of EGR Boost Sensor Circuit Leave ignition off and EGR boost sensor harness connector disconnected. Disconnect PCM 104-pin harness connector. Inspect pins for damage and repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Turn ignition on. Measure resistance between test pin No. 34 and EGR boost sensor signal circuit at harness connector. Measure resistance between test pin No. 91 and EGR boost sensor ground circuit at harness connector. If resistance for both circuits is less than 5 ohms, go to next step. If resistance for either circuit is 5 ohms or greater, inspect and repair suspect circuit. Repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  9. Check EGR Boost Sensor Circuit For Short To Ground Leave ignition off and EGR boost sensor disconnected. Disconnect scan tool from DLC (if applicable). Measure resistance between test pin No. 34 and test pins No. 91 (SIG RTN), 51 and No. 103 (PWR GND) at breakout box. Measure resistance between test pin No. 34 and test pins No. 71, 90 and 97 at breakout box. If resistance is 10 k/ohms or more on all circuits, go to next step. If resistance is less than 10 k/ohms on any circuit, repair short in suspect circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  10. Check VPWR At EGR Valve Turn ignition off. Disconnect EGR valve. Turn ignition on. Measure voltage between VPWR terminal of EGR valve wiring harness connector and chassis ground. If voltage is 10.5 volts or more, go to next step. If voltage is less than 10.5 volts, repair open VPWR circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  11. Check EGR Control Circuits For Short To Ground Or Power Leave ignition off and disconnect EGR valve connector. Disconnect scan tool from DLC (if applicable). Measure resistance between test pins No. 46, 56, 68 and 72 and negative battery terminal. If each measurement is 10 k/ohms or more, go to next step. If any measurement is less than 10 k/ohms, repair short in suspect circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  12. Check Continuity Of EGR Valve Control Circuits Ensure EGR valve and PCM connectors are disconnected. Measure resistance between specified breakout box test pins and EGR valve harness connector terminals. See «EGR VALVE-TO-PCM CIRCUIT IDENTIFICATION»(ref-91102-S29275888842001030200000) table. If resistance is less than 5 ohms for all circuits, replace EGR valve and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If resistance is 5 ohms or greater on any circuit, inspect and repair suspect circuit. Repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
Test Pin No.EGR Terminal
46B
56F
68E
72A

EGR VALVE-TO-PCM CIRCUIT IDENTIFICATION

DTC indicates that PCM has detected EVAP control system has excessive fuel tank vacuum. Possible causes are

  1. EVAP canister purge tube blocked or kinked.
  2. Fuel vapor elbow on EVAP canister is contaminated.
  3. Restricted EVAP canister.
  4. EVAP Canister Purge (CANP) valve stuck open.
  5. Fuel filler cap stuck closed (no vacuum relief).
  6. Open in VREF circuit.
  7. Faulty Fuel Tank Pressure (FTP) sensor.
  1. Check Purge Solenoid Valve Ensure freeze frame data is recorded. Remove vacuum hose from intake manifold input on purge solenoid valve. Apply 8.4 in. Hg of vacuum to open port on solenoid part of valve. If vacuum is rapidly released, go to next step. If vacuum is not rapidly released, replace purge solenoid valve. Repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  2. Check Purge Solenoid Valve Resistance Turn ignition off. Measure resistance between solenoid terminals. If resistance is 30-36 ohms, go to next step. If resistance is not 30-36 ohms, replace purge solenoid valve. Clear PCM Memory and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  3. Check Purge Solenoid Valve Circuit Continuity Turn ignition off. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pin No. 67 and test pins No. 24 and 103. If resistance is greater than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in circuit. Clear PCM memory and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  4. Check FTP Sensor VPWR Circuit Continuity Turn ignition off. Disconnect FTP VPWR terminal on FTP sensor harness connector. If resistance is less than 5 ohms, replace FTP sensor and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If resistance is 5 ohms or greater, repair open VPWR circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .

DTC indicates an CDCV circuit fault. Possible causes are

  1. Open VPWR circuit.
  2. Open or shorted CDCV circuit.
  3. Faulty CDCV.
  4. Faulty PCM.
  1. Check VPWR Circuit To CDCV Ensure freeze frame data is recorded. Turn ignition off. Disconnect and inspect CDCV connector. Turn ignition on. Measure voltage between VPWR terminal at CDCV harness connector and negative battery terminal. If voltage is greater than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open in VPWR circuit.
  2. Check CDCV Resistance Turn ignition off. Measure resistance between CDCV terminals. If resistance is 45-65 ohms, go to next step. If resistance is not 45-65 ohms, replace CV solenoid and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  3. Check CDCV Circuit Resistance Disconnect PCM 104-pin wiring harness connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pin No. 18 at breakout box and CV terminal at CDCV harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in VREF circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  4. Check CDCV Circuit For Short To Ground Disconnect scan tool. Measure resistance between test pin No. 18 and test pins No. 51 and 103 at breakout box. If resistance reading is less than 10 k/ohms, repair CDCV circuit short to ground. If resistance reading is 10 k/ohms or more, reconnect scan tool and go to next step.
  5. Check CDCV Circuit For Short To PWR Turn ignition on. Measure voltage between chassis ground and test pin No. 18 at breakout box. If voltage is less than one volt, go to next step. If voltage is one volt or more, repair CDCV circuit short to PWR, VREF, VPWR or chassis ground. Repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  6. Check CDCV Signal From PCM Turn ignition off. Reconnect CDCV solenoid connector. Connect PCM to breakout box. Start engine and allow to idle. Measure voltage between test pin No. 18 and test pin No. 51 or 103 at breakout box. If voltage is 10-14 volts, replace CDCV solenoid. If voltage is not 10-14 volts, replace PCM.

DTC indicates that IAC system has reached overspeed (engine speed is 200 RPM more than requested RPM) malfunction. Possible causes are as follows

  1. IAC circuit short to ground.
  2. IAC assembly stuck open.
  3. Air intake leaks or restrictions.
  4. Damaged throttle body.
  5. Contaminated or damaged IAC valve assembly.
  6. Faulty Powertrain Control Module (PCM).
  1. Check System For Vacuum Leaks Ensure freeze frame data is recorded. Check entire system for vacuum leaks. Repair or replace as necessary. If no vacuum leaks are found, go to next step.
  2. Check EVAP System Turn ignition off. Disconnect hoses from EVAP canister purge valve or solenoid. Attach vacuum pump with gauge to carbon canister hose port. Using vacuum pump, apply 16 in. Hg to port. If vacuum bleeds off within 20 seconds, replace EVAP canister purge valve or solenoid and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If vacuum is not bled off immediately, go to next step.
  3. Check IAC Solenoid Function Start engine and allow to idle. Ensure transmission is in Park or Neutral and engine is warmed to normal operating temperature. Disconnect IAC solenoid wiring harness connector. If engine speed drops, go to next step. If engine speed does not drop, check throttle body for damage. If throttle body is okay, replace IAC solenoid and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  4. Check IAC Circuit For Short To Ground Turn ignition off. Disconnect scan tool from DLC. Disconnect PCM wiring harness connector. Inspect pins for damage and repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pin No. 83 (IAC) and test pins No. 51 and 103 (PWR GND) at breakout box. If resistance is greater than 10 k/ohms and idle speed is normal, go to next step. If resistance is greater than 10 k/ohms and high idle speed is present, replace PCM and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If resistance is less than 10 k/ohms, repair circuit short to ground and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  5. Check IAC System For Intermittent Open Or Short Circuit Connect scan tool to DLC. Ensure all accessories are off and engine is warmed to normal operating temperature. Turn ignition on. Using scan tool, access IAC PID and RPM PID. IAC duty cycle should be 20-40 percent. Observe IAC PID and RPM PID for indication of fault while wiggling and bending wiring harness between IAC solenoid and PCM. Fault will be indicated by sudden change in IAC PID or RPM PID value. If any faults are found, isolate and repair as necessary. Repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If no faults are found, problem cannot be duplicated at this time. Ensure all applicable connections are clean and tight, and go to «DIAGNOSTIC TEST Z (INTERMITTENT)»(ref-91102-S20258564262001030200000) .

DTC P1650 indicates PSP signal is out of self-test range. Possible causes for this fault are as follows

  1. Open or short in wiring harness.
  2. Faulty PSP switch.
  3. Faulty PSP switch/shorting bar damage.
  4. Faulty Powertrain Control Module (PCM).
  1. Verify Electrical Function Ensure freeze frame data is recorded. Start engine and allow to idle. Using scan tool, access PSP PID (if scan tool cannot access PSP PID, go to next step). Turn steering wheel left, then right. If scan tool does not indicate on/off switching, go to next step. If scan tool indicates on/off switching, ensure all applicable connections are clean and tight, and go to «DIAGNOSTIC TEST Z (INTERMITTENT)»(ref-91102-S20258564262001030200000) .
  2. Check PSP Switch Operation Turn ignition off. Install tachometer. Start engine and allow to idle. Disconnect PSP switch. Connect jumper wire between harness terminal and ground. If engine speed increases, replace switch and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If engine speed does not increase, go to next step.
  3. Check PSP Circuit Resistance Turn ignition off. Disconnect jumper wire. Leave PSP switch disconnected. Turn ignition off. Disconnect 104-pin PCM connector. Inspect connector for damage and repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pin No. 31 (PSP) at breakout box and PSP terminal of PSP switch connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair open circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  4. Check For Short In PSP Circuit Leave ignition off and PSP switch disconnected. Measure resistance between test pins No. 31 (PSP) and 91 at breakout box. Measure resistance between test pin No. 31 and chassis ground. If both resistance measurements are 10 k/ohms or more, go to next step. If resistance is less than 10 k/ohms, repair short circuit and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .
  5. Check Switch Resistance Turn ignition off. Disconnect PSP switch. Start engine and allow to idle. Measure resistance between PSP switch signal and chassis ground while turning steering wheel. If resistance is less than 10 ohms, replace PCM and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If resistance is 10 ohms or more, replace PSP switch and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .

PSP switch is always on at IAC system monitoring condition (vehicle speed more than 37 MPH). Possible causes are

  1. Damaged PSP switch.
  2. Faulty PCM.
  3. PSP signal circuit short to ground.
  1. Verify Electrical Function Ensure freeze frame data is recorded. Turn ignition on. Using scan tool, select PSP PID. Observe PID and turn steering wheel left, then right. If PID value does not indicate a change, go to next step. If PID value indicates a change, go to «DIAGNOSTIC TEST Z (INTERMITTENT)»(ref-91102-S20258564262001030200000) .
  2. Check PSP Switch Operation Start and idle engine. Using scan tool, select RPM PID. Disconnect PSP switch connector. Connect jumper wire between harness terminal and ground. If RPM increases, replace PSP switch and repeat «QUICK TEST»(ref-91102-S14663847332001030200000) . If RPM does not increase, go to next step.
  3. Check PSP Circuit Resistance Turn ignition off. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance of PSP circuit between test pin No. 31 at breakout box and PSP terminal at PSP switch wiring harness connector. Also, measure resistance of SIG RTN circuit between test pin No. 91 at breakout box and SIG RTN terminal at PSP switch wiring harness connector. If both resistance readings are less than 5 ohms, go to next step. If any resistance reading is 5 ohms or more, repair open in PSP or SIG RTN circuit.
  4. Check For Short In PSP Circuit Measure resistance between test pins No. 31 and 91 at breakout box. Also, measure resistance between test pin No. 31 and chassis ground. If both resistance readings are 10 k/ohms or more, replace PCM. If any resistance reading is less than 10 k/ohms, repair short circuit.

DTC P1703 indicates voltage was seen at brake switch input during KOEO self test. Possible causes for this fault are as follows

  1. Brake pedal applied during KOEO self test.
  2. Faulty brake switch.
  3. Brake switch input shorted to power.
  1. Ensure brake pedal was not applied during KOEO self test. Retest if pedal was applied. Go to next step.
  2. Turn ignition on. Using scan tool, check BOO PID. Apply brake pedal several times. If BOO PID stays on, go to next step. If BOO PID switches on and off, problem is intermittent. Check brake switch. See SYSTEM & COMPONENT TESTING - EXCEPT B2500, B3000 & B4000 article. Repair or replace as necessary. If no problem is found, go to «DIAGNOSTIC TEST Z (INTERMITTENT)»(ref-91102-S20258564262001030200000) .
  3. Check voltage (backprobe) between 104-pin PCM harness connector terminal No. 92 (White/Green wire) and ground. If 10.5 volts or more is present at PCM connector terminal No. 92 (White/Green wire), go to next step. If less than 10.5 volts is present at PCM connector terminal No. 92 (White/Green wire), replace PCM.
  4. Disconnect brake switch. Check voltage at harness connector. If 10.5 volts or more is present at White/Green wire terminal, go to next step. If 10.5 volts or more is present at only Yellow/Red wire terminal, replace switch and retest.
  5. Turn ignition off. Disconnect cruise control module. Turn ignition on. If 10.5 volts or more is present at brake switch harness connector terminal (White/Green wire), go to next step. If less than 10.5 volts is present at brake switch harness connector terminal (White/Green wire), replace cruise control module.
  6. Turn ignition off. Disconnect ABS or ABS/TCS control module. Turn ignition on. If 10.5 volts or more is present at brake switch harness connector terminal (White/Green wire), go to next step. If less than 10.5 volts is present at brake switch harness connector terminal (White/Green wire), replace ABS or ABS/TCS control module.
  7. Diagnose and repair short to power on White/Green wire between brake switch, PCM, cruise control module, ABS or ABS/TCS control module and brake lights. See WIRING DIAGRAMS article. After repair, repeat «QUICK TEST»(ref-91102-S14663847332001030200000) .

More articles — Engine Controls - Self-Diagnostics