P0813Generic code

P0813 Code: Reverse Output Circuit

The P0813 code means there is an electrical fault in the control circuit of the reverse output. It can cause backup lights or a camera that do not work. Check the fuse, relay, connector and wiring, including the trailer wiring, before you replace anything.

Severity
Low
Can I keep driving?
Yes, no immediate risk
Estimated cost
$20 to $300
Difficulty
Medium
System
Transmission
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P0813 code means

The computer turns on a circuit when reverse gear is engaged. That circuit powers the backup lights and notifies other systems (the camera, the parking sensors and the mirrors).

The computer watches the control circuit from its own driver transistor. The P0813 code points to an electrical fault in that control circuit. Before you replace the component, check the fuse, relay, connector and wiring, because they are the most common cause.

If the circuit fails, the backup lights or the camera can stop working. Check the bulbs and the trailer wiring, which is a frequent cause of shorts.

Always start with the simplest items: fuse, relay and connector. Then check power, ground and signal with the component connected (using back-probes), and finally the continuity of each wire up to the computer. Only if all of that is good should you replace the component.

P0813 code symptoms

  • Check engine light or another warning light on.
  • Backup lights or camera that do not work.

Likely causes of the P0813 code

  1. Damaged connector, loose, broken or corroded.
  2. Blown or faulty fuse or relay.
  3. Wiring cut or shorted between the component and the computer.
  4. Failed component: the coil, the motor or its internal electronics.

How to diagnose the P0813 code step by step

  1. Command the component with the scan tool and see whether it responds.
  2. Check the fuse and relay. Measure voltage on both sides of the fuse, and swap the relay with an identical one.
  3. Measure the supply at the connector. Battery voltage with the key on or when it is commanded.
  4. Measure the component resistance and compare it with the manual, and check the insulation to ground too.
  5. Check the control wire for continuity up to the computer and for shorts.

How to fix the P0813 code

  • Repair the connector, the wiring or the power supply.
  • Replace the reverse output circuit if it does not respond with correct power and command.
  • Clear the codes and verify the repair.

Technical reference data

  • 12 V output when reverse is engaged.
  • These are approximate values: check the manufacturer data for your vehicle.

Brand-specific notes

The wiring of a trailer hitch is a common cause of shorts, so unplug the trailer connector and check whether the code returns.

Frequently asked questions about P0813

What does the P0813 code mean?
It is a generic OBD2 code that means there is an electrical fault in the control circuit of the reverse output. That circuit powers the backup lights and notifies the camera and other systems.
Can I drive with a P0813 code?
Yes, with caution. The backup lights or the camera may not work, so take extra care when you back up.
What does the reverse output circuit do?
The computer turns on a circuit when reverse gear is engaged. It powers the backup lights and notifies other systems such as the camera, the parking sensors and the mirrors.
Does the part always have to be replaced?
No. Check the fuses, relays, connectors and wiring first.
How much does it cost to fix P0813?
As a rough guide, between $20 and $300.
Will a P0813 code clear itself?
It can go out if the fault was a momentary bad connection, but a blown fuse or a short in the wiring will bring the P0813 code back.
What is the most common cause of P0813?
A damaged connector, a blown fuse or relay, or cut or shorted wiring. Trailer hitch wiring is a frequent source of shorts.

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