Cylinder 1 Misfire

DTC P0301: Cylinder 1 misfire detected

NOTE: If some of the DTCs listed below are stored at the some time as a misfire DTC, troubleshoot those DTCs first, then recheck for the misfire DTC.

P0131, P0132: Primary HO2S
P0171, P0172: Fuel supply system
P0401: EGR system
P1359, P1361, P1362: TDC sensor
P1381, P1382: CYP sensor

1. Start the engine, listen for a clicking sound at the fuel injector in the problem cylinder.
Does it click?
YES-Go to step 2.
NO-Go to step 11.
2. After checking and recording the freeze data, do the ECM/PCM Reset Procedure. If there is no freeze data of misfiring, just clear the DTC.
3. Exchange the spark plug from the problem cylinder with one from another cylinder.
4. Test-drive the vehicle several times in the range of the freeze data or under various conditions if there was no freeze data.
5. Check the DTC and the Temporary DTC with the scan tool.
Is DTC P0301, P0302, P0303 or P0304, or Temporary DTC P1399 indicated?
YES-Go to step 6.
NO-Intermittent misfire due to spark plug fouling, etc. (no misfire at this time).
6. Determine which cylinder(s) had the misfire. Does the misfire occur in the other cylinder whose spark plug was exchanged?
YES-Replace the faulty spark plug.
NO-Go to step 7.
7. Exchange the fuel injector from the problem cylinder with one from another cylinder.
8. Let the engine idle for two minutes.
9. Test-drive the vehicle several times in the range of the freeze data or under various conditions if there was no freeze data.
Is DTC P0301, P0302, P0303 or P0304, or Temporary DTC P1399 indicated?
YES-Go to step 10.
NO-Intermittent misfire due to bad contact in the fuel injector connector (no misfire at this time).
10. Determine which cylinder(s) had the misfire.
Does the misfire occur in the other cylinder whose fuel injector was exchanged?
YES-Replace the faulty fuel injector.
NO-Check the engine compression and perform a cylinder leak down test.
11. Check for an open or short in the harness between the ECM/PCM and the fuel injector.
Are the wires OK?
YES-Go to step 12.
NO-Repair open or short in the wire.
12. Install a known-good fuel injector, and recheck. Does the injector click?
YES-Replace the fuel injector.
NO-Substitute a known-good ECM/PCM and recheck. If the symptom/indication goes away, replace the original ECM/PCM.
Diagnostic Strategies