P0891

SYMPTOM
P0891 - TRANSMISSION RELAY ALWAYS ON

WHEN MONITORED
When the ignition is turned from the "OFF" position to the "RUN" position and/or the ignition is turned from the "CRANK" position to the "RUN" position.

SET CONDITION
This DTC set if the Transmission Control Module (TCM) senses greater than 3 volts at the Transmission Control Relay Output circuits at the TCM prior to the TCM energizing the relay. Note: Due to the integration of the Powertrain and Transmission Control Modules, the transmission part of the PCM has its own specific power and ground circuits.

POSSIBLE CAUSES
- Intermittent wiring and connectors
- Transmission control relay stuck closed
- Transmission control relay output circuit short to voltage
- Transmission relay control circuit short to voltage
- PCM - transmission relay always ON