P2311 OBD-II Trouble Code: Ignition Coil D Secondary Circuit

Check Engine Light

P2311 code definition

Ignition Coil D Secondary Circuit

What the P2311 code means

P2311 is an OBD-II generic code for the engine control module (ECM) detecting ignition that coil D or the cylinder 4 secondary circuit has low ionization. This means the coils spark is not lasting long enough.

What causes the P2311 code?

  • The spark plug coil secondary circuit (to include the coil, coil boot or the spark plug) is shorted or open causing excessive resistance in the coil secondary circuit.

  • The coil primary has internal shorted windings and causes the secondary voltage to be low.

  • The primary return wiring is shorted to ground or cut in the harness back to the ECM.

What are the symptoms of the P2311 code?

  • The Check Engine Light will be illuminated and code P2311 set in ECM memory as a fault

  • The engine will run rough or misfire

  • The engine may run pretty good and then all of a sudden run very rough when the short occurs

  • The engine may only misfire under a load when the secondary voltage needs to be at its highest

How does a mechanic diagnose the P2311 code?

  • Scans for codes in the ECM and documents them then looks at the freeze frame data for failure

  • Checks the coil for carbon tracking, cracks or the wiring harness having been cut into causing the short

  • Checks the coil output with a spark checker

  • Removes the coil connection and tests the coil for shorted primary windings

  • Checks the wiring harness for shorts or open circuits from coil to the ECM

  • Checks the spark plug for cracks or a worn electrode

Common mistakes when diagnosing the P2311 code?

  • Clearing ECM memory codes before checking the freeze frame data for the main failure problem, so the failure may be duplicated and repaired.

  • Trying to test the coil without a spark tester. This may burn out the ECM coil driver if a proper tool is not used.

How serious is the P2311 code?

  • Code P2311 is a code indicating that the coil secondary spark is not good enough. This may be due to the plugs being worn or cracked.This can also be due to spark grounding inside the head through the plug boot or the coil itself.

What repairs can fix the P2311 code?

Additional comments for consideration regarding the P2311 code

Code P2311 is caused most commonly from an internal coil primary circuit short or open windings. The failure may burn out the ECM coil driver. If the coil and ECM are not replaced at the same time, the ECM may get burned; it should be replaced with a new coil. Always check the coil primary and secondary resistance for problems if replacing the ECM. It is also recommended to replace the spark plug boot and plug.

Need help with a P2311 code?

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