U0135 moderate

Lost Communication With Differential Control Module -- Front

The U0135 code means the vehicle's onboard diagnostic system has detected: Lost Communication With Differential Control Module -- Front. This is a moderate severity code.

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Keep driving?
Short distances only
DIY difficulty
hard
Estimated cost
$200 - $1200 (parts and labor)
Diagnose CAN Bus Issues
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Network codes mean modules are not communicating. You need a scanner that reads all systems to find the problem.

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Common Symptoms

  • AWD or 4WD warning light on
  • Front differential not engaging
  • Grinding noise from front differential area
  • Check Engine Light may be on
  • Reduced traction in AWD/4WD mode

Probable Causes (Ranked by Likelihood)

  • Failed front differential control module Very High
  • Damaged wiring to front differential module High
  • Front differential actuator motor failure Moderate
  • Low differential fluid causing module fault Moderate
  • Corroded connector at differential module Low

Step-by-Step Diagnostic Procedure

  1. Scan for DTCs in the 4WD/AWD and transfer case modules

  2. Check front differential fluid level and condition

  3. Inspect wiring and connector at the front differential module

  4. Verify power supply and ground at the module

  5. Test the front differential actuator motor for operation

Frequently Asked Questions

Can I drive with code U0135?

You can drive short distances in two-wheel drive mode on paved roads. Do not attempt off-road driving or use 4WD mode as the front differential may not be engaging properly.

What causes U0135?

A failed front differential control module or damaged wiring are the most common causes. Low differential fluid or a failed actuator motor can also trigger this code.

Should I check the differential fluid?

Yes. Low or contaminated differential fluid is an easy item to check and can cause module communication issues. If the fluid is dark, has metal particles, or smells burnt, a fluid change and further inspection are needed.

Sources

This page is built from documented references. Verify against your own service info before repair work.

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