OBD Guide
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B1556

Ignition Run/Start Circuit Open

B1556 is an OBD-II diagnostic trouble code meaning: Ignition Run/Start Circuit Open. Common causes: broken or damaged wiring harness, faulty ignition relay. Estimated repair cost: $56–167.

Severity
🔴 High
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Engine won't start
  • Problems starting the engine
  • Check Engine Light Is On

Causes

  • Broken or damaged wiring harness
  • Faulty ignition relay
  • Problems with the ignition switch
  • Short circuit in the circuit
  • Engine control unit (ECU) malfunction

How to Fix

  1. Check the wiring harness for breaks or damage
  2. Check the ignition relay and replace if necessary
  3. Check the ignition switch for malfunctions
  4. Check circuit for short circuit
  5. If necessary, replace the engine control unit (ECU)

Related codes

P0351P0352B1555

FAQ

What does the B1556 code mean?

B1556 is an OBD-II diagnostic trouble code that indicates: Ignition Run/Start Circuit Open

What causes a B1556 error code?

The most common causes of B1556 include: Broken or damaged wiring harness; Faulty ignition relay; Problems with the ignition switch; Short circuit in the circuit.

How do I fix a B1556 diagnostic trouble code?

To fix B1556: Check the wiring harness for breaks or damage. Check the ignition relay and replace if necessary. Check the ignition switch for malfunctions. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B1556?

Yes, but get it checked soon

How much does it cost to fix B1556?

The estimated repair cost for B1556 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat