OBD Guide

P0812

Reverse Input Circuit

P0812 is an OBD-II diagnostic trouble code meaning: Reverse Input Circuit. Common causes: open or short circuit in reverse circuit, transmission position sensor malfunction. Estimated repair cost: $6–56.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$6–56 (est.)

Symptoms

  • Check Engine Light Is On
  • Incorrect engine operation when reverse gear is engaged
  • No signal on the instrument panel when reverse gear is engaged
  • Gear shifting problems (on some models)

Causes

  • Open or short circuit in reverse circuit
  • Transmission position sensor malfunction
  • Reverse switch damage
  • Oxidation or poor contact in connectors
  • ECU problems (rare)

How to Fix

  1. Check the integrity of the reverse circuit
  2. Check the condition of the gearbox position sensor
  3. Inspect the reverse switch
  4. Clean contacts in circuit connectors
  5. If necessary, replace faulty components

Related codes

Error P0812 by Vehicle Brand

FAQ

What does the P0812 code mean?

P0812 is an OBD-II diagnostic trouble code that indicates: Reverse Input Circuit

What causes a P0812 error code?

The most common causes of P0812 include: Open or short circuit in reverse circuit; Transmission position sensor malfunction; Reverse switch damage; Oxidation or poor contact in connectors.

How do I fix a P0812 diagnostic trouble code?

To fix P0812: Check the integrity of the reverse circuit. Check the condition of the gearbox position sensor. Inspect the reverse switch. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0812?

Yes, but get it checked soon

How much does it cost to fix P0812?

The estimated repair cost for P0812 is $6–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat