P0813 Fault Code

Reverse Output Circuit

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0813 fault code refers to an issue with the reverse output circuit in a vehicle's transmission system. This code is typically triggered when the engine control module (ECM) detects a problem with the signal received from the reverse switch. The reverse switch is responsible for informing the ECM when the transmission is in reverse gear, which in turn activates various functions such as reverse lights and certain safety features.

What are the symptoms of the P0813 code?

Common symptoms associated with the P0813 fault code include:

• The reverse lights do not illuminate when the vehicle is in reverse.
• Difficulty shifting into reverse or a lack of engagement.
• Possible illumination of the check engine light.
• Transmission may potentially enter failsafe mode, leading to limited functionality.

What causes the P0813 code?

Several factors can lead to a P0813 code including:

• A faulty reverse switch that fails to send the correct signal.
• Wiring issues such as damaged, corroded, or shorted wires in the reverse switch circuit.
• Poor connections or loose wiring harness connectors.
• Malfunctioning ECM that fails to interpret signals accurately.
• Improper transmission fluid levels or contamination affecting transmission components.

How to fix P0813?

To resolve the P0813 fault code, follow these steps:

• Check and replace the reverse switch if it is found to be faulty or malfunctioning.
• Inspect the wiring and connectors for any signs of damage or corrosion; repair or replace as necessary.
• Ensure that the transmission fluid levels are correct and the fluid is clean.
• Reset the ECM after repairs to clear the fault code and test drive the vehicle to confirm the issue is resolved.