P0813 Reverse Output Circuit

P0813 indicates a reverse output circuit fault. The module cannot correctly drive or monitor the circuit used for reverse-related output control.

Code status

Needs verification

Not yet verified against SAE J2012_202509 / J2012DA. Treat unverified rows as a lookup aid, not repair authority.

System: Transmission
Scope: iso-sae-controlled-p0
Standard: SAE J2012 / ISO 15031-6
Source: legacy-import

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not assume the reverse switch is bad if the code identifies an output circuit.

Useful checks before replacing parts

Check reverse output command, circuit voltage, load condition, fuse feed, ground path, and the device controlled by the output.
Inspect wiring to reverse lamps, relay, camera trigger, transmission control device, or other vehicle-specific reverse output loads.
Review module data to see whether the reverse input is correct before diagnosing the output side of the circuit.

Related OBD-II codes

These nearby transmission entries can help compare wording and fault area. They may share the same verification status as the source database.