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Test H: Fuel Control: Testing

    NOTE: For additional testing information, see DIAGNOSTIC AIDS  and DTC DESCRIPTIONS  .
    NOTE: HO2S may be displayed as O2S on scan tool.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 1) to step 11). No test procedures have been omitted.

  1. 1) DTC P0130-P0134, P0136-P0140 Or P1148: HO2S Circuit Malfunction
    Ensure engine is at normal operating temperature. Connect scan tool to Data Link Connector (DLC). Using scan tool, access appropriate HO2S PID from PID/DATA MONITOR & RECORD menu. Start engine. Operate engine at specified speeds while observing HO2S PID voltage reading. See HO2S OPERATING SPECIFICATIONS  table. If HO2S PID reading does not agree with specifications, is fixed, or is less than .33 volt or more than .99 volt, leave scan tool connected and go to next step. If HO2S PID reading agrees with specifications, turn ignition off. If directed here to diagnose DTCs P0131, P0132, P0133 or P1148, go to step  20). If directed here for any other DTC, fault may be intermittent. Go to TEST Z  , step  1), or go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - VILLAGER article.

  2. 11) Check HO2S Output Voltage

    Using scan tool, access appropriate HO2S PID from PID/DATA MONITOR & RECORD menu. Start engine and observe HO2S PID voltage reading while raising engine speed to 2000 RPM. If HO2S PID ever increases to more than .5 volt, go to step  14). If HO2S PID never increases to more than .5 volt, go to next step.
    3. NOTE: Vehicles with Federal emissions use HO2S-11 only.

  3. 12) Check Continuity Of HO2S Signal Circuit
    Turn ignition off. Disconnect suspect HO2S connector. Disconnect PCM harness connector. Inspect connector for damaged pins and repair if necessary. Using DVOM, measure resistance of suspect HO2S-11 or HO2S-12 circuits between HO2S harness connector and PCM harness connector. See HO2S, HTR, INJ1-6 & KAPWR CIRCUIT IDENTIFICATION  table. See Figure and Figure . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in affected circuit. See WIRING DIAGRAMS article.

  4. 13) Check HO2S-11 Or HO2S-12 Circuit For Short To Ground

    Ensure ignition is off. Using DVOM, measure resistance between suspect HO2S-11 or HO2S-12 and GND circuits at PCM harness connector. See PCM TERMINAL CIRCUIT IDENTIFICATION  and HO2S, HTR, INJ1-6 & KAPWR CIRCUIT IDENTIFICATION  table. See Figure. If resistance is 10 k/ohms or less repair short between circuits. If resistance is more than 10 k/ohms, go to step  40). If all systems check okay, go to step  15).

  5. 14) Check HO2S-11 Or HO2S-12 Circuit For Short To Power

    Using DVOM, measure resistance between HO2S-11 or HO2S-12 and KAPWR circuit at PCM harness connector. See HO2S, HTR, INJ1-6 & KAPWR CIRCUIT IDENTIFICATION  table. See Figure. If resistance is 10 k/ohms or less, repair short between circuits. See WIRING DIAGRAMS article. If resistance is more than 10 k/ohms, go to next step.

  6. 15) Erase DTCs

    Connect all disconnected components. Erase all DTCs. See CLEARING CODES . Start engine and operate at 1500-2000 RPM for more than 3 minutes. Repeat QUICK TEST . If same DTC you were directed for is not present, go to TEST Z  , step  1), or go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - VILLAGER article. If same DTC is present, turn ignition off. If directed here to diagnose DTCs P0131, P0132, P0133 or P1148, go to step  20). If directed here for any other DTC, replace damaged HO2S. Repeat QUICK TEST . If DTC is still present, replace PCM.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 15) to step 20). No test procedures have been omitted.
    7. NOTE: For additional testing information, see DIAGNOSTIC AIDS  and DTC DESCRIPTIONS  .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 20) to step 22). No test procedures have been omitted.

  7. 20) DTC P0135 & P0141: Heater Circuit Malfunction
    Examine HO2S harness connectors for damage or corrosion. Repair connectors as necessary. If HO2S harness connectors are okay, go to step  22).
    8. NOTE: This step may generate unrelated DTCs. Clear all DTCs after this test step is performed.

  8. 22) Check Appropriate HO2S Heater Circuit
    Disconnect suspect HO2S-11 or HO2S-12 harness connectors. Using DVOM, measure voltage between HTR-11 or HTR-12 and GND circuits at appropriate HO2S harness connector. Start engine and monitor appropriate heater voltage. Voltage will be high (battery voltage) with heater on and low (less than one volt) with heater off. Heater voltage should be low for 5 seconds (heater off) after engine starts, then stay high (heater on) at idle. Increase engine speed to more than 3200 RPM. Heater voltage should be low (heater off) at more than 3200 RPM, then stay high (heater on) at less than 3200 RPM. If heater voltage stays low for 5 seconds after engine starts, becomes high at idle and changes to low at more than 3200 RPM, go to step  26). If heater voltage stays high, go to next step. If heater voltage stays low, go to step  24).

  9. 23) Check HTR-11 Or HTR-12 Circuit For Short To Ground

    Ensure suspect HO2S is disconnected. Disconnect PCM connector. Using DVOM, measure resistance between HTR-11 or HTR-12 and GND circuits at PCM harness connector. See PCM TERMINAL CIRCUIT IDENTIFICATION  and HO2S, HTR, INJ1-6 & KAPWR CIRCUIT IDENTIFICATION  table. See Figure and Figure . If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short between circuits. See WIRING DIAGRAMS article.

  10. 24) Check Continuity Of VPWR Circuit

    Ensure suspect HO2S is disconnected. Turn ignition on. Using DVOM, measure voltage between chassis ground and VPWR circuit at suspect HO2S harness connector. See Figure. If voltage is more than 10 volts, go to next step. If voltage is 10.5 volts or less, repair open in affected circuit. See WIRING DIAGRAMS article.

  11. 25) Check Continuity Of HTR-11 Or HTR-12 Control Circuit

    Using DVOM, measure resistance of suspect HTR-11 or HTR-12 circuit between HO2S harness connector and PCM harness connector. See HO2S, HTR, INJ1-6 & KAPWR CIRCUIT IDENTIFICATION  table. See Figure and Figure . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in affected circuit.

  12. 26) Check HO2S Heater

    Ensure suspect HO2S is disconnected. Using DVOM, measure resistance between HO2S connector HTR and VPWR circuits. If resistance is not about 6 ohms, replace faulty HO2S. If resistance is about 6 ohms, replace PCM.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 26) to step 40). No test procedures have been omitted.
    13. NOTE: For additional testing information, see DIAGNOSTIC AIDS  and DTC DESCRIPTIONS  .
    NOTE: Before servicing DTCs P0171 and P0172, verify with customer that vehicle did not run out of fuel before CHECK ENGINE light came on.

  13. 40) DTC P0171 & P0172: Fuel Trim Malfunction
    Possible causes for DTC P0171 are as follows:
    • Intake air leaks.
    • Damaged or disconnected front HO2S or circuit.
    • Plugged injectors.
    • Fuel pressure regulator stuck open.
    • Exhaust gas leaks.
    • Incorrect fuel pressure.
    • Lack of fuel.
    • Faulty MAF sensor.
    • Faulty PCV system.
    • Oil overfill.
    • Incorrect cam timing.
    • Low compression.
    • Faulty coil and secondary side of ignition system.

    Possible causes for DTC P0172 are as follows:

    • Damaged or disconnected HO2S-11 sensor or connector.
    • Exhaust gas leaks.
    • Incorrect fuel pressure.
    • Leaking fuel injector(s).
    • Leaking fuel pressure regulator.
    • Faulty MAF sensor.
    • Faulty PCV system.
    • Oil overfill.
    • Incorrect cam timing.
    • Low compression.
    • Faulty coil and secondary side of ignition system.

    If any of the listed areas are faulty, repair as necessary. If all of the listed areas are okay, go to next step.

    14. WARNING: Before performing this test step, release fuel system pressure to reduce risk of injury or fire. See FUEL SYSTEM PRESSURE RELEASE under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - VILLAGER article.
    NOTE: Before performing the following test step, determine whether misfire DTCs are displayed with fuel control DTCs. Use misfire DTCs to determine which injector circuits require testing. Disconnecting PCM erases Continuous Memory DTCs.

  14. 41) Fuel Delivery System
    Connect fuel pressure gauge to fuel rail or fuel filter. Start engine and observe fuel pressure. If fuel pressure is 34-43 psi (234-294 kPa), go to next step. If fuel pressure is zero psi (zero kPa), go to TEST HC  , step  3). If fuel pressure is less than 34 psi (234 kPa), go to TEST HC  , step  20). If fuel pressure is 43 psi (294 kPa) or more, go to TEST HC  , step  30).

  15. 42) Check Injector Harness & Resistance

    Turn ignition off. Disconnect PCM. Using DVOM, measure resistance of suspect injector between injector (INJ1-6) circuit and PCM KAPWR circuit at PCM harness connector. See HO2S, HTR, INJ1-6 & KAPWR CIRCUIT IDENTIFICATION  table. If each injector and circuit resistance is 10-14 ohms, injector and circuit resistance are okay. Go to step  45). If injector and circuit resistance is not 10-14 ohms, go to next step.

  16. 43) Check Injector Circuit Resistance

    Ensure ignition is off. Disconnect injector harness connector. Using DVOM, measure resistance of KAPWR circuit and injector signal (INJ1-6) circuit between injector harness connector and PCM harness connector. See Figure and Figure . See HO2S, HTR, INJ1-6 & KAPWR CIRCUIT IDENTIFICATION  table. If each circuit resistance is less than 5 ohms, go to next step. If either circuit resistance is 5 ohms or more, repair open in affected circuit. See WIRING DIAGRAMS article.

  17. 44) Check Injector Harness Circuit For Short To Power Or Ground

    Using DVOM, measure resistance between injector signal (INJ1-6) and KAPWR, GND and SIG RTN circuits at PCM harness connector. See PCM TERMINAL CIRCUIT IDENTIFICATION  and HO2S, HTR, INJ1-6 & KAPWR CIRCUIT IDENTIFICATION  tables. Also, measure resistance between chassis ground and injector signal circuit at PCM harness connector. See Figure. If each circuit resistance is more than 10 k/ohms, go to next step. If any circuit resistance is 10 k/ohms or less, repair short to ground or between affected circuits.

  18. 45) Check Injector Driver Signal

    Reconnect PCM harness connector. Connect a standard non-powered test light between KAPWR circuit and injector signal (INJ1-6) circuits at each injector harness connector. See HO2S, HTR, INJ1-6 & KAPWR CIRCUIT IDENTIFICATION  table. See Figure. Crank engine. If test light dimly glows while cranking, go to next step. If test light does not glow or glows brightly, replace PCM.

  19. 46) Flow Test Fuel Injectors

    Using Rotunda Fuel Injector Tester (164-R3759) or generic fuel injector tester, check flow rate of each injector. Follow tester instructions. Replace any injectors that are not within leakage and flow specification. If all injectors are within leakage and flow specification, fault may be intermittent. Go to TEST Z  , step  1), or go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - VILLAGER article.
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