P0813
UniversalReverse Output Circuit Malfunction
Medium SeverityThis code indicates a fault within the circuit responsible for signaling that the transmission is in reverse gear. This typically impacts safety features such as the proper operation of your reverse lights and backup camera.
⚠️ Before You Begin (Safety First)
Always practice caution when working on any vehicle. Ensure the vehicle is parked on a level surface and the parking brake is engaged. Disconnect the battery before performing any electrical work to prevent accidental short circuits or injury. Wear appropriate safety gear such as gloves and eye protection.
Common Symptoms
- Reverse lights do not illuminate
- Backup camera does not activate
- No power to reverse accessories
- Check Engine Light (CEL) illuminated
- Park assist features may malfunction
Common Causes
- Faulty reverse light switch or sensor
- Damaged, corroded, or shorted wiring in the reverse circuit
- Blown fuse related to the reverse circuit
- Faulty transmission range sensor (which may include the reverse switch function)
- Malfunctioning Body Control Module (BCM) or Powertrain Control Module (PCM) (less common)
Frequently reported on: General/Universal
Diagnostic Steps
- Inspect the reverse light bulbs for any signs of being burnt out and replace if necessary.
- Locate and inspect the fuse(s) associated with the reverse lights or transmission control system. Replace any blown fuses.
- Find the reverse light switch or transmission range sensor, typically located on the transmission or shifter assembly. Check its electrical connector for corrosion or damage.
- Visually inspect the wiring harness leading to the reverse switch/sensor and reverse lights for any obvious damage, frayed wires, or corrosion.
- If accessible and you have a multimeter, test for continuity across the reverse switch when activated and check for voltage at the reverse light bulb sockets when reverse is engaged.
👨🔧 When to Call a Professional
If you are uncomfortable performing electrical diagnostic tests or if the issue persists after checking basic components like fuses and switches, it is best to consult a professional automotive technician. Complex wiring issues or internal transmission sensor failures may require specialized tools and expertise.
Commonly Asked Questions
What does the P0813 code specifically indicate?
The P0813 code indicates a general malfunction within the electrical circuit that signals to the vehicle's computer when the transmission is in reverse gear.
Can I still drive my car with a P0813 code?
Yes, you can usually drive your car, but your reverse lights or backup camera may not function. This reduces safety when backing up, so it's advised to get it repaired promptly.
What is the most common cause of a P0813 code?
The most frequent causes include a faulty reverse light switch, a blown fuse, or damaged wiring in the reverse light circuit.
Is fixing a P0813 code expensive?
Often, the repair is relatively inexpensive, especially if it's just a blown fuse or a faulty reverse light switch. Costs can rise if the issue is a more complex wiring problem or a transmission internal sensor.
Where is the reverse light switch located?
The reverse light switch is typically located on the transmission casing itself, or sometimes integrated into the transmission range sensor or shifter assembly.