P0813 code meaning
Reverse Output Circuit
What P0813 means
P0813 concerns a signal 'reverse active' that a module puts out – usually the transmission module, on manual cars the engine or body module – for example to the back-up lamp relay, the reversing camera or the body module. Like other driver outputs it is checked by comparing commanded and actual state, which reveals an open circuit or a short. Saab's 2012 transmission module reports a short to positive on its park/neutral output in the same way. No manufacturer document with thresholds for the reverse output is available to us. Back-up lamps, camera or mirror tilt may stop working; driving itself is not affected, and CARB allows such outputs without the MIL.
P0813 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0813
- Back-up lamps not working
- Reversing camera or parking beeper does not activate
- Stored code without driving effects
Common causes of P0813
- Most likelyWire from module to relay or body module open or shorted
- PossibleBack-up lamp relay or connected load faulty
- PossibleConnector corroded
- Less likelyModule output stage faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Reverse output circuitBackup lamp relayTransmission control module
What each part of P0813 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 8 | Area: transmission. |
| 13 | The exact fault in that area. |
What to do next
- Note P0813 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0813
What does P0813 mean?
P0813 means "Reverse Output Circuit". P0813 concerns a signal 'reverse active' that a module puts out – usually the transmission module, on manual cars the engine or body module – for example to the back-up lamp relay, the reversing camera or the body module. It is a generic code, so it means the same on every make.
Is it safe to drive with P0813?
P0813 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will P0813 fail an emissions test?
P0813 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is P0813 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0813 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.