Code Definition

P0889 — TCM Power Relay Sense Circuit Range/Performance

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0889

P0889 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0889 is stored, the module has detected a plausibility fault — the measured value is in the electrical range but is not consistent with expected operating behaviour.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P0889 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The fault code P0889 is triggered when the control module identifies a range or performance issue in the Transmission Control Module (TCM) power relay sense circuit. This code indicates that the signal or performance of the sense circuit, which monitors the status and operation of the TCM power relay, is falling outside the expected range or behaving erratically. Proper functioning of this circuit is critical for the control module to accurately assess the power relay's status, which in turn affects the power supply to the TCM and, subsequently, transmission operations.

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