OBD Guide
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B2990

A/C Compressor Driving Circuit

B2990 is an OBD-II diagnostic trouble code meaning: A/C Compressor Driving Circuit. Common causes: open or shorted wiring harness, faulty compressor relay. Estimated repair cost: $56–222.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$56–222 (est.)

Symptoms

  • Air conditioner doesn't work
  • Floating idle speed
  • Check Engine Light Is On
  • The compressor does not turn on

Causes

  • Open or shorted wiring harness
  • Faulty compressor relay
  • Problems with the climate control unit
  • Damaged compressor solenoid valve
  • Poor contact in connectors

How to Fix

  1. Check compressor circuit fuse
  2. Diagnose the compressor control relay
  3. Check the integrity of the wiring harness from the control unit to the compressor
  4. Test compressor solenoid valve winding resistance
  5. Check the operation of the climate control control unit

Related codes

B2991B2992P0532

FAQ

What does the B2990 code mean?

B2990 is an OBD-II diagnostic trouble code that indicates: A/C Compressor Driving Circuit

What causes a B2990 error code?

The most common causes of B2990 include: Open or shorted wiring harness; Faulty compressor relay; Problems with the climate control unit; Damaged compressor solenoid valve.

How do I fix a B2990 diagnostic trouble code?

To fix B2990: Check compressor circuit fuse. Diagnose the compressor control relay. Check the integrity of the wiring harness from the control unit to the compressor. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B2990?

Yes, but get it checked soon

How much does it cost to fix B2990?

The estimated repair cost for B2990 is $56–222. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat