Code Definition

P0812 — Reverse Input Circuit

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

About P0812

P0812 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 P0812 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

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 P0812 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

Fault code P0812 is set when the vehicle's powertrain control module (PCM) or transmission control module (TCM) detects an issue with the reverse input circuit. This circuit is responsible for signalling the activation of the reverse gear in vehicles. The issue can arise from a malfunction in the circuit that informs the control modules when the vehicle is in reverse gear. This malfunction can be electrical or mechanical and affects the vehicle's ability to engage or recognise the reverse gear properly.

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