Diagnostic Aids
WARNING: This page is about a different variant/trim than selected.
- A misfire DTC could be caused by an excessive vibration from sources other than the engine. Inspect for the following possible sources:
- A tire or wheel that is out of round or out of balance
- Variable thickness brake rotors
- An unbalanced drive shaft
- Certain rough road conditions
- Transmission operation
- Cracked Spark Plug Insulators
- Broken or weak valve spring
- A damaged or defective accessory drive component or belt; remove the belt and safely operate the engine to evaluate if misfire counts go away.
- High resistance in the circuits of the injectors may set a misfire DTC without setting an injector DTC. Test the injector circuits of the affected cylinder(s) for a high resistance if you suspect a condition.
- If the condition is intermittent, observing the scan tool IC Circuit Test and Fuel Injector Circuit Test Status parameters may help isolate the condition. The circuit test status parameters will change from OK or Not Run to Fault/Malfunction if a condition exists.
- A condition in the heated O2 sensor (HO2S) heater control circuits may set a DTC P0300.