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DTC P1130, P1150: Ho2S Not Switching: Condition

DTCs P1130 and P1150 indicate fuel system has reached maximum compensation and HO2S is not switching at the adaptive limits. Possible causes are:

Inspect engine for obvious defects in specified systems. Repair as necessary. If no faults are found, go to next step.

  1. DTCs P1130 And P1150: Fuel System Not Switching At Fuel Trim

    Check intake air system for leaks and damage. Verify integrity of PCV system. Check for vacuum leaks. If a problem is found, repair as necessary and go to step 17). If no problem is found, go to next step.

  2. Perform KOER SELF-TEST

    Turn ignition off. Connect scan tool to DLC. Disconnect fuel vapor hose from intake manifold. Start engine, and operate at 2000 RPM for 5 minutes. Perform KOER ON-DEMAND SELF-TEST. See QUICK TEST in TESTS W/CODES - INTRODUCTION article. If DTCs P1131 and/or P1151 are present, go to next step. If DTCs P1131 and/or P1151 are not present, repair EVAP system as necessary.

  3. HO2S Circuit Test (With Lean DTCs)

    Disconnect suspect HO2S. Turn ignition on. Using scan tool, select appropriate HO2S PID from PID/DATA monitor menu. Connect a jumper wire between HO2S SIG and VPWR terminals at suspect HO2S wiring harness connector. If spark occurs, remove jumper wire and go to step 6). If HO2S voltage is more than 1.3 volts, go to next step. If voltage is 1.3 volts or less, go to step 6).

  4. Check Signal Return 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). Connect PCM to breakout box. Measure resistance between negative battery terminal and SIG RTN terminal at suspect HO2S wiring harness connector. If resistance is less than 5 ohms, reconnect all components and go to step 9). If resistance is 5 ohms or more, check wiring and go to next step.

  5. Check For Open Circuit

    Turn ignition off. Disconnect PCM from breakout box. Measure resistance between test pin No. 91 (SIG RTN) at breakout box and SIG RTN terminal at suspect HO2S wiring harness connector. If resistance is less than 5 ohms, replace PCM and go to step 17). If resistance is 5 ohms or more, repair open circuit and go to step 17).

  6. Check Resistance Of HO2S SIG & Ground Circuits

    Turn ignition off. Install breakout box, leaving PCM disconnected. Disconnect suspect HO2S connector. Inspect connectors for loose, damaged or corroded terminals. Repair as necessary. Measure resistance of HO2S SIG circuit between HO2S SIG terminal at suspect HO2S wiring harness connector and appropriate HO2S SIG test pin at breakout box as follows:
    • HO2S 11, test pin No. 60.
    • HO2S 21, test pin No. 87.

    Measure resistance between SIG RTN terminal at suspect HO2S wiring harness connector and test pin No. 91 at breakout box. If all resistance readings are less than 5 ohms, go to next step. If any resistance reading is 5 ohms or more, repair open circuit and go to step 17).

  7. Check HO2S Circuit For Short To Ground

    Measure resistance between test pins No. 24, 51, 77, 91 and 103 and appropriate HO2S SIG test pin at breakout box as follows:
    • HO2S 11, test pin No. 60.
    • HO2S 21, test pin No. 87.

    If all resistance readings are more than 10 k/ohms, go to next step. If any resistance reading is 10 k/ohms or less, repair short circuit and go to step 17).

  8. Check HO2S For Short To Ground

    Reconnect HO2S connector. Measure resistance between test pins No. 25, 91 and 103 and appropriate HO2S SIG test pin at breakout box as follows:
    • HO2S 11, test pin No. 60.
    • HO2S 21, test pin No. 87.

    If any resistance reading is 10 k/ohms or less, replace HO2S and go to step 17). If all resistance readings are more than 10 k/ohms, replace PCM and go to step 17).

  9. Check Fuel Pressure

    Release fuel system pressure. See BASIC TESTING article. With ignition off, install fuel pressure gauge. Verify vacuum source to fuel pressure regulator (returnable fuel system only). Start engine and allow to idle. Record fuel pressure. Increase engine speed to 2000 RPM and maintain for one minute. Record fuel pressure. If engine will not start, cycle key on and off several times and record fuel pressure. Fuel pressure should be 30-45 psi (2.1-3.1 kg/cm2 ). If fuel system pressure is not as specified, see BASIC TESTING article. If fuel system pressure is as specified, go to next step.

  10. Check Ability To Hold Fuel Pressure

    With fuel pressure gauge installed, cycle ignition from OFF to ON position 3-4 times to pressurize fuel system (DO NOT start engine). Note fuel pressure. If fuel pressure remains within 5 psi (.4 kg/cm2 ) of maximum pressure for at least one minute, go to next step. If fuel pressure drops more than 5 psi (.4 kg/cm2 ) within one minute, repair fuel system. See BASIC TESTING article.

  11. Check Fuel Injector Flow & Leakage

    Turn ignition off. Remove breakout box. Reconnect PCM and fuel injector connector(s). Use Rotunda fuel injector tester from Fuel Tester Kit (113-00114) to flow test fuel injectors. Follow injector tester instructions. If fuel injector flow or leakage rate is not okay, replace defective fuel injector(s) and go to step 17). If flow rate for each fuel injector is okay, go to next step.

  12. Check Air Induction System

    Check air induction system for leaks. Check PCV system for leaks. Check vacuum hoses for damage and tight connections. Check intake manifold gaskets. Check air intake tube from air cleaner to throttle body. If any faults are found, repair as necessary. After repair, go to step 17). If no faults are found, go to next step.

  13. Check Cylinder Compression

    Using compression gauge, check cylinder compression. If cylinder compression is not okay, repair engine as necessary and go to step 17). If compression is okay, go to next step.

  14. Check HO2S Integrity

    Turn ignition off. Inspect HO2S wiring harness for chafing, burned wires or other damage. Repair as necessary. Disconnect suspect HO2S connector. Connect DVOM between SIG RTN terminal and HO2S SIG terminal at suspect HO2S. Start engine and operate at 2000 RPM for 3 minutes. Perform KOER ON-DEMAND SELF-TEST while monitoring HO2S voltage. If HO2S voltage is more than .5 volt during or at end of test, go to next step. If voltage is .5 volt or less, replace HO2S sensor and go to step 17).

  15. Monitor HO2S PID

    Start engine and allow to idle. Ensure engine is at normal operating temperature. Using scan tool, select HO2S PID from PID/DATA monitor menu. Observe PID value while wiggling and bending wiring harness between HO2S and PCM. If PID voltage stays high (more than .45 volt) or stays low (less than .45 volt), isolate fault and repair as necessary. After repairs, go to step 17). If PID voltage switches, go to next step.

  16. Monitor HO2S PID During Test Drive

    Using an assistant, test drive vehicle under various conditions while observing HO2S PID. If PID voltage switches properly, unable to duplicate fault. Go to next step. If voltage does not switch properly, replace HO2S and go to next step.

  17. Verify Repair

    Clear DTCs and perform quick test. See QUICK TEST in TESTS W/CODES - INTRODUCTION article.
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