Diagnostic Procedures

WARNING: This page is about a different variant/trim than selected.

If powertrain diagnostic system check was performed, go to next step. If powertrain diagnostic system check was not performed, go to POWERTRAIN DIAGNOSTIC SYSTEM CHECK under DIAGNOSTIC SYSTEM TESTS. After performing powertrain diagnostic system check, go to next step.
CAUTION: Before performing this diagnostic test, CKP system variation learn procedure must be completed. See CRANKSHAFT POSITION SENSOR VARIATION LEARN PROCEDURE under PROGRAMMING.

NOTE: Ensure ABS and traction control system are operating properly before beginning this diagnostic test. If any DTCs other than P0135 and P0155 are set, repair those DTCs first. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .
Start and operate engine at idle. Using scan tool, select MISFIRE DATA LIST function and monitor MISFIRE CUR. COUNTERS (one counter per cylinder). If any misfire counter is incrementing, go to step 4. If misfire counter is not incrementing, go to next step.
Turn ignition on, engine off. Review FREEZE FRAME and/or FAILURE RECORDS data for this DTC and observe parameters. Turn ignition off for at least 30 seconds. Start engine. Operate vehicle within conditions required to set this DTC. Using scan tool select DTC option and SPECIFIC DTC option, then enter this DTC. If scan tool indicates that this DTC failed this ignition, go to next step. If scan tool does not indicate that this DTC failed this ignition, see DIAGNOSTIC AIDS .
If only one cylinder is misfiring, go to step 6. If more than one of cylinders is misfiring, go to next step.
Check if any of the following conditions exist:
- Using scan tool, check HO2S readings. If signal is fixed less than 200 mV go to DTC P0131: HO2S CIRCUIT VOLTAGE LOW - BANK 1, SENSOR 1; DTC P0151: HO2S CIRCUIT LOW VOLTAGE DTC P0151: HO2S CIRCUIT LOW VOLTAGE - BANK 2, SENSOR 1 . If signal is fixed greater than 900 mV go to DTC P0132: HO2S CIRCUIT VOLTAGE HIGH - BANK 1, SENSOR 1; P0152: HO2S CIRCUIT HIGH VOLTAGE P0152: HO2S CIRCUIT HIGH VOLTAGE - BANK 2, SENSOR 1 .
- Check that accessory drive pulleys are not misaligned.
- Check vacuum hoses for splits, kinks and proper routing. See Figure.
- Check for leaks at throttle body, intake manifold, EGR valve or PCV system.
- Check PCM grounds for proper connection.
- Check that all injector harness connectors are connected to proper injector/cylinder. Check for blown INJ fuses.
- Test fuel pressure. See appropriate BASIC DIAGNOSTIC PROCEDURES article.
- Check for restricted exhaust system.
- Check for fuel contamination.
If any conditions are present, repair as necessary. After repairs, go to step 17. If conditions are not present and repair is not necessary, go to next step.
Turn ignition off. Disconnect suspect injector connector corresponding to misfire counter that was incrementing. Connect Injector Test Light (J-34730-2C) to connector of suspect injector. Start engine. If injector test light if flashing, go to next step. If injector test light is not flashing, go to DTC P0200: INJECTOR CONTROL CIRCUIT .
Turn ignition off. Reconnect suspect injector connector. Disconnect suspect ignition wire to spark plug that corresponds to misfire current counter that was incrementing. Install Spark Plug Tester (J-26792) to spark plug wire. Start engine. If spark is present at spark plug tester, go to step 9. If spark is not present, go to next step.
Disconnect suspect ignition wire from ignition coil. Using DVOM, measure resistance of suspect spark plug wire. If resistance is less than 700 ohms, replace ignition wire. If resistance is not less than 700 ohms, go to step 16.
Remove and check spark plug from suspect cylinder. If spark plug is okay, go to next step. If spark plug is faulty, go to step 11.
Swap spark plug to another cylinder that is operating properly. Operate vehicle under same conditions that misfire occurred. If misfire moved with spark plug, go to step 15. If misfire is still present at original cylinder, perform fuel injector coil test. See appropriate SYSTEM & COMPONENT TESTING article. If injector coil test does not isolate condition, diagnose engine mechanical condition and repair as necessary.
If spark plug is fouled with oil or coolant, diagnose mechanical engine problem and repair as necessary. If spark plug is not fouled with oil or coolant, go to next step.
Check if spark plug is fouled with gasoline. If spark plug is not gasoline fouled, go to next step. If spark plug is gasoline fouled, diagnose fuel system. See appropriate SYSTEM & COMPONENT TESTING article. If fuel system diagnosis does not isolate condition, diagnose engine mechanical condition and repair as necessary.
Check spark plug for signs of cracks, wear or improper gap. If spark plug is faulty, go to next step. If spark plug is okay, perform fuel injector coil test. See appropriate SYSTEM & COMPONENT TESTING article. If injector coil test does not isolate condition, diagnose engine mechanical condition and repair as necessary.
Replace or re-gap spark plug. After replacing or re-gapping spark plug, go to step 17.
Replace faulty spark plug(s). After replacing spark plug(s), go to step 17.
Replace faulty spark plug wire. After replacing spark plug wire, go to next step.
If complaint is due to MIL flashing, perform DTC P0420: CATALYST SYSTEM LOW EFFICIENCY - BANK 1; P0430: CATALYST SYSTEM LOW EFFICIENCY - BANK 2 . If MIL is not flashing, go to next step.
Using scan tool, clear DTCs. Turn ignition off for at least 30 seconds. Start engine and allow it to reach normal operating temperature. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2.
Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no undiagnosed DTCs are displayed, system is okay.