Fuel and air

P01D8 — Cylinder 7 Injection Timing Over-Advanced

Severity: medium Drive with care, to a shop

What P01D8 means

The engine control module compares the actual start of fuel injection in cylinder 7 with the commanded timing. P01D8 sets when injection begins noticeably earlier than it should, meaning it is over-advanced. The cause can be the injector, its wiring, control or calibration errors, or a problem with engine timing.

Symptoms

  • Check Engine light on
  • Rough idle
  • Reduced power and sluggish acceleration
  • Higher fuel consumption
  • Knocking or abnormal engine noise under load
  • Possible misfire on cylinder 7

Possible causes

  1. Faulty or sticking cylinder 7 fuel injector
  2. Open, shorted or corroded wiring or connector at the injector
  3. Low or unstable fuel pressure
  4. Intake air leak skewing the mixture
  5. ECM software or calibration fault, or bad sensor feedback
  6. Mechanical valve or engine timing problem (chain, belt, phaser)

How to diagnose

  1. Scan all codes and freeze frame data, and look for related injector, misfire or cam/crank correlation codes.
  2. Review short-term and long-term fuel trims and mixture adaptation values.
  3. Inspect the cylinder 7 injector connector and harness for damage, corrosion and chafing.
  4. Test injector resistance and the control signal with a meter or scope.
  5. Compare cylinder balance and run an injector cut-off test with a scan tool if available.
  6. Measure fuel pressure at idle and under load.
  7. Check the intake and exhaust for air leaks.
  8. Verify cam and crank correlation and the condition of the timing drive.

Common fixes

  • Clean or replace the cylinder 7 injector
  • Repair the injector wiring or connector
  • Fix air leaks and fuel supply faults
  • Update or reflash the ECM software per manufacturer bulletins
  • Correct the timing system fault if a timing offset is found

Questions and answers

What does P01D8 mean?

The ECM found that fuel injection in cylinder 7 starts too early compared with the commanded timing. The most common causes are the injector, its wiring or an injection control issue.

Can I drive with P01D8?

Only briefly and with light loads to get to a shop. Extended driving risks knock, misfires and engine damage.

How do I fix P01D8?

Start by checking the cylinder 7 injector wiring and connector, fuel pressure and air leaks. If those are fine, the injector is replaced or the ECM software is updated.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.