OBD Guide
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U1525

HVAC Control Module Lost Communication With Coolant Heater Control Module On LIN Bus

U1525 is an OBD-II diagnostic trouble code meaning: HVAC Control Module Lost Communication With Coolant Heater Control Module On LIN Bus. Common causes: broken or damaged lin bus wires, hvac module malfunction. Estimated repair cost: $56–167.

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

Symptoms

  • The climate control system does not work
  • No coolant heating
  • Check Engine Light Is On
  • Some HVAC functions do not work

Causes

  • Broken or damaged LIN bus wires
  • HVAC module malfunction
  • Malfunction of the coolant heating control module
  • Problems with module power supply
  • Contact corrosion

How to Fix

  1. Check the integrity of the LIN bus wires
  2. Check power supply of modules
  3. Check connections and contacts for corrosion
  4. Scan modules for errors
  5. Replace the faulty module if necessary

Related codes

U1526U1524

FAQ

What does the U1525 code mean?

U1525 is an OBD-II diagnostic trouble code that indicates: HVAC Control Module Lost Communication With Coolant Heater Control Module On LIN Bus

What causes a U1525 error code?

The most common causes of U1525 include: Broken or damaged LIN bus wires; HVAC module malfunction; Malfunction of the coolant heating control module; Problems with module power supply.

How do I fix a U1525 diagnostic trouble code?

To fix U1525: Check the integrity of the LIN bus wires. Check power supply of modules. Check connections and contacts for corrosion. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U1525?

Yes, but get it checked soon

How much does it cost to fix U1525?

The estimated repair cost for U1525 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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