Powertrain
generic / SAE
P0812
Reverse Input Circuit
General electrical fault on the reverse-engagement input — the signal that tells the TCM (and other modules — backup lights, parking sensors) that the gear lever is in Reverse. With the input invalid backup lights and rear sensors do not activate.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number8 / 12
Possible causes
- Open or shorted reverse input wire high
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Inspection / repair
- Difficulty: medium
- DIY: possible
- Estimated cost: 60–300 €
- Estimated time: 0.3–1.5 h
- Component: reverse input switch
- Component: wiring harness
- MIL / check engine light
Sources
References
sae:J2012