OBD Guide

P0851

Park/Neutral Switch Input Circuit Low

P0851 is an OBD-II diagnostic trouble code meaning: Park/Neutral Switch Input Circuit Low. Common causes: faulty park/neutral switch, open or short circuit in the circuit. Estimated repair cost: $6–33.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$6–33 (est.)

Symptoms

  • Problems starting the engine
  • Unstable operation at idle
  • Activating emergency mode
  • Check Engine Light Is On
  • Inability to change gears

Causes

  • Faulty park/neutral switch
  • Open or short circuit in the circuit
  • Poor contact in connectors
  • Engine control unit (ECU) malfunction
  • Wiring harness damage

How to Fix

  1. Check the condition of the park/neutral switch
  2. Inspect the circuit for breaks or short circuits
  3. Check contacts in connectors
  4. Test the operation of the engine control unit
  5. Replace damaged components

Related codes

Error P0851 by Vehicle Brand

FAQ

What does the P0851 code mean?

P0851 is an OBD-II diagnostic trouble code that indicates: Park/Neutral Switch Input Circuit Low

What causes a P0851 error code?

The most common causes of P0851 include: Faulty park/neutral switch; Open or short circuit in the circuit; Poor contact in connectors; Engine control unit (ECU) malfunction.

How do I fix a P0851 diagnostic trouble code?

To fix P0851: Check the condition of the park/neutral switch. Inspect the circuit for breaks or short circuits. Check contacts in connectors. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0851?

Yes, but get it checked soon

How much does it cost to fix P0851?

The estimated repair cost for P0851 is $6–33. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat