OBD Guide

P2D42

A/C Compressor Motor Voltage B Low

P2D42 is an OBD-II diagnostic trouble code meaning: A/C Compressor Motor Voltage B Low. Common causes: problems with wiring or contacts in the motor circuit, compressor motor malfunction. Estimated repair cost: $56–278.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$56–278 (est.)

Symptoms

  • The air conditioner does not turn on or operates intermittently
  • Reduced interior cooling efficiency
  • Check Engine light comes on
  • Noise or knocking noise coming from the compressor area
  • The air conditioning system turns off automatically

Causes

  • Problems with wiring or contacts in the motor circuit
  • Compressor motor malfunction
  • Relay or fuse problems
  • Air conditioner control module malfunction
  • Short circuit in the circuit

How to Fix

  1. Check the condition of fuses and relays
  2. Diagnose the motor power supply circuit for opens and short circuits
  3. Check contacts and connections in the circuit
  4. Test the compressor motor
  5. If necessary, replace the motor or compressor assembly

Related codes

Error P2D42 by Vehicle Brand

FAQ

What does the P2D42 code mean?

P2D42 is an OBD-II diagnostic trouble code that indicates: A/C Compressor Motor Voltage B Low

What causes a P2D42 error code?

The most common causes of P2D42 include: Problems with wiring or contacts in the motor circuit; Compressor motor malfunction; Relay or fuse problems; Air conditioner control module malfunction.

How do I fix a P2D42 diagnostic trouble code?

To fix P2D42: Check the condition of fuses and relays. Diagnose the motor power supply circuit for opens and short circuits. Check contacts and connections in the circuit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P2D42?

Yes, but get it checked soon

How much does it cost to fix P2D42?

The estimated repair cost for P2D42 is $56–278. Actual cost depends on your vehicle, location, and labor rates.

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