OBD Guide
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C1551

Power Supply Voltage Malfunction

C1551 is an OBD-II diagnostic trouble code meaning: Power Supply Voltage Malfunction. Common causes: low battery, generator malfunction. Estimated repair cost: $6–167.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$6–167 (est.)

Symptoms

  • SRS/Airbag light is on
  • Disabling the restraint system
  • Voltage-related errors in other systems

Causes

  • Low battery
  • Generator malfunction
  • Damaged wiring harness
  • Oxidized or poor contacts
  • SRS control unit malfunction

How to Fix

  1. Check battery voltage (should be 12.6V with engine off)
  2. Check the generator voltage (should be 13.8-14.4V with the engine running)
  3. Inspect the SRS wiring harness for damage.
  4. Clean the contacts in the SRS unit connectors
  5. Diagnose the SRS control unit

Related codes

B1000B1015U0121

FAQ

What does the C1551 code mean?

C1551 is an OBD-II diagnostic trouble code that indicates: Power Supply Voltage Malfunction

What causes a C1551 error code?

The most common causes of C1551 include: Low battery; Generator malfunction; Damaged wiring harness; Oxidized or poor contacts.

How do I fix a C1551 diagnostic trouble code?

To fix C1551: Check battery voltage (should be 12.6V with engine off). Check the generator voltage (should be 13.8-14.4V with the engine running). Inspect the SRS wiring harness for damage.. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with C1551?

Do not drive — repair immediately

How much does it cost to fix C1551?

The estimated repair cost for C1551 is $6–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat