OBD Guide

P25B9

Auxiliary Ignition Switch On/Start Position Circuit High

P25B9 is an OBD-II diagnostic trouble code meaning: Auxiliary Ignition Switch On/Start Position Circuit High. Common causes: short circuit to positive in the circuit, ignition relay malfunction. Estimated repair cost: $17–56.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$17–56 (est.)

Symptoms

  • Difficulty starting the engine
  • engine stalls after starting
  • blinking lights on the dashboard
  • unstable operation of the ignition system

Causes

  • short circuit to positive in the circuit
  • ignition relay malfunction
  • wiring harness damage
  • poor contact in connectors
  • ignition switch malfunction

How to Fix

  1. Check the voltage in the ignition circuit
  2. Inspect relays and fuses
  3. Check the condition of the wiring harness
  4. Test the ignition switch
  5. Replace damaged components

Related codes

Error P25B9 by Vehicle Brand

FAQ

What does the P25B9 code mean?

P25B9 is an OBD-II diagnostic trouble code that indicates: Auxiliary Ignition Switch On/Start Position Circuit High

What causes a P25B9 error code?

The most common causes of P25B9 include: short circuit to positive in the circuit; ignition relay malfunction; wiring harness damage; poor contact in connectors.

How do I fix a P25B9 diagnostic trouble code?

To fix P25B9: Check the voltage in the ignition circuit. Inspect relays and fuses. Check the condition of the wiring harness. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P25B9?

Yes, but get it checked soon

How much does it cost to fix P25B9?

The estimated repair cost for P25B9 is $17–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat