What does it mean?
On this type of engine the module does not assume that an injector fires exactly when it is told to; it verifies the result. By analysing how the crankshaft accelerates during each firing event, and where the hardware allows by reading needle-lift or combustion-pressure feedback, it works out when combustion in cylinder 10 really started. Storing this code means that start of combustion was consistently later than the commanded point, beyond the retard limit written into the calibration. A late burn loses expansion work, drops the torque contribution of cylinder 10 and leaves more unburned fuel in the exhaust. The monitor only runs with the engine warm and the load steady, so the code reflects a repeatable deviation rather than one odd event.
Symptoms
- MIL (check engine lamp) on and, in many cases, a stored misfire code for the same cylinder.
- The engine idles roughly and the vibration can be felt through the pedals and the steering wheel.
- Sluggish throttle response and a flat spot when accelerating.
- Difficult cold starting with extended cranking and a puff of smoke when the engine catches.
- Fuel consumption creeps up and the exhaust smells strongly of unburned fuel.
- Some vehicles restrict engine output and enter limp mode once the fault has repeated.
Likely causes
- An injector on cylinder 10 that has become sluggish through wear, carbon build-up or internal deposits.
- Calibration or trim codes never written after a replacement, or copied from the wrong injector.
- Insufficient high-pressure rail pressure while the monitor is running, so the nozzle starts to deliver later than planned.
- Voltage drop in the injector supply or return path: a loose connector pin, a corroded splice or a poor ground.
- Contaminated fuel, water in the fuel, or air drawn into the high-pressure circuit through a leaking union.
- Timing drive wear such as chain stretch, a worn tensioner or an incorrectly installed belt, which offsets the crankshaft reference.
- A weakening injector driver stage inside the control module.
How to fix it
- Note the freeze frame conditions, then reproduce them on a road test while logging the relevant data.
- Log the injector correction values for every cylinder and see how far cylinder 10 sits from the group.
- Verify that actual rail pressure follows the commanded value at idle, part load and full load.
- Test the injector circuit for cylinder 10: measure winding resistance, check for a clean ground and confirm the drive signal with a scope or current clamp where available.
- Perform a return-flow test with the engine running to identify a nozzle passing more fuel than the others.
- Inspect the timing drive and verify camshaft-to-crankshaft correlation if the deviation shows on more than one cylinder.
- Once the injector is replaced or reconditioned, program its calibration code, carry out the injector learning procedure and confirm the corrected value on a follow-up road test.