P2691: Cylinder 6 Injector Data Incompatible

What it means

The flow calibration data programmed for cylinder 6 injector does not match the format expected by the controller software.

At a glance

• Usually lights the check-engine light

How it works

The engine controller uses flow calibration data to account for differences between individual fuel injectors. P2691 sets when the data associated with the cylinder 6 injector is in a format or version the controller does not accept.

Common causes

Most likely first.

1. Replacement injector has different part number than software expects
2. Calibration code format does not match controller version

Symptoms

• Check-engine light
• Possible rough running or reduced power

How to diagnose it

1. Read freeze-frame data and any injector calibration or programming faults to see whether the code appeared after work on cylinder 6.
2. Check service records and the cylinder 6 injector label against the part and calibration data specified for the vehicle.
3. Inspect the cylinder 6 injector connector and nearby harness for loose pins, damage, or signs that the injector was recently replaced.
4. Use a capable scan tool to read the stored cylinder 6 injector calibration and compare its format with the controller's requirements.
5. If the injector and data are correct, verify that the controller software supports that calibration version before considering reprogramming.

Common fixes

• Enter the correct cylinder 6 injector calibration data using a compatible scan tool.
• Replace an incorrectly specified cylinder 6 injector with the correct compatible unit.
• Update or reconfigure the controller software if the manufacturer supports the injector calibration version.

Can I keep driving?

If the engine runs smoothly, a short, gentle drive may be possible, but avoid heavy loads if it runs rough or loses power. Continued incorrect cylinder 6 fueling can worsen drivability and may increase engine wear.