P2159

Diagnostic trouble code (DTC) information ECM-P215904

Condition
The Engine control module (ECM) monitors the information that comes from other control modules. The transmission control module (TCM) and the brake control module (BCM) inform, among other things, about the vehicle speed, via the controller area network (CAN). The information is used by the engine control module (ECM) for, among other things, controlling idle speed. The engine control module (ECM) checks the vehicle speed signals by comparing them with each other. The speed signal from the brake control module (BCM) is the main signal. The speed signal from the transmission control module (TCM) is the reference signal.
The diagnostic trouble code (DTC) is stored if the control module detects that:
- The quality of the speed signal from the transmission control module (TCM) is too low.
The control module's test for the diagnostic trouble code (DTC) starts in the event of:
- Engine running.

Substitute value

- None.

Possible source

- Incorrect speed signal from the transmission control module (TCM).
- Contact resistance in the control area network (CAN) terminals.
- Open-circuit in one or both CAN cables.

Fault symptom[s]
- Malfunction indicator light (MIL), on
- Uneven idle