OBD Guide

B1390

Control Module Supply Circuit 1

B1390 is an OBD-II diagnostic trouble code meaning: Control Module Supply Circuit 1. Common causes: poor contact in the power circuit, broken or damaged wires. Estimated repair cost: $33–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$33–167 (est.)

Symptoms

  • Unstable engine operation
  • Power dips
  • Check Engine Light Is On
  • Malfunctions of the car's electronic systems

Causes

  • Poor contact in the power circuit
  • Broken or damaged wires
  • Faulty relay or fuse
  • Battery or alternator problems
  • Malfunction of the control module itself

How to Fix

  1. Check fuses and relays associated with the control module
  2. Inspect the wiring harness for damage
  3. Check the contacts in the control module connectors
  4. Test the voltage in the power circuit
  5. If necessary, replace the control module

Related codes

FAQ

What does the B1390 code mean?

B1390 is an OBD-II diagnostic trouble code that indicates: Control Module Supply Circuit 1

What causes a B1390 error code?

The most common causes of B1390 include: Poor contact in the power circuit; Broken or damaged wires; Faulty relay or fuse; Battery or alternator problems.

How do I fix a B1390 diagnostic trouble code?

To fix B1390: Check fuses and relays associated with the control module. Inspect the wiring harness for damage. Check the contacts in the control module connectors. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B1390?

Limited driving only, diagnose soon

How much does it cost to fix B1390?

The estimated repair cost for B1390 is $33–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat