U0135

Universal

Lost Communication With Differential Control ModuleFront

Definition source: General OBD-II reference catalog
Definition verification: Not independently verified for display.
Time: Varies by diagnosis and vehicle | Diagnostic difficulty: Medium
Medium Severity

The vehicle has detected that other control modules cannot communicate with the front differential control module. That module may help manage differential operation, so its loss of communication could affect related driveline functions or trigger warning lights. The code identifies a communication problem, not proof that the module itself has failed.

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⚠️ Before You Begin (Safety First)

If the vehicle behaves unpredictably, loses drive, or displays a serious driveline or stability warning, stop somewhere safe and arrange professional assessment. If it drives normally, have the fault diagnosed promptly; exact risks depend on the vehicle.

Common Symptoms

  • A driveline or differential warning may appear if the vehicle reports the communication loss to the driver.
  • A traction or stability warning may appear if related functions depend on information from the differential control module.
  • The vehicle may have changes in differential or driveline behavior, depending on how the system is designed.
  • There may be no noticeable symptoms if the communication loss is intermittent or the affected function is not currently needed.

Common Causes

  • A loose, damaged, corroded, or contaminated connector may interrupt communication with the differential control module.
  • Damaged wiring or a network-circuit fault may prevent messages from reaching the module.
  • A problem with the module’s power supply or ground may make it unavailable to other modules.
  • A fault elsewhere on the vehicle communication network may disrupt messages to or from the module.
  • The differential control module itself may have failed, but this should be confirmed after its circuits and network connections are checked.

Diagnostic Steps

  1. Note any driveline, traction, or stability warnings and changes in vehicle behavior; this information can help guide diagnosis.
  2. With the vehicle safely parked and the ignition off, visually check accessible related connectors and wiring for looseness, visible damage, or corrosion. Do not unplug connectors unless the vehicle-specific service information says it is safe.
  3. Check the vehicle battery and charging system condition using the owner’s manual guidance, since weak electrical supply can contribute to communication problems.
  4. Use a compatible scan tool, if available, to record all module codes before clearing anything. Check whether other modules also report communication faults.
  5. If wiring or connector damage is not obvious, or the fault returns, arrange vehicle-specific electrical and network testing rather than replacing the control module based only on this code.

When to Call a Professional

A technician can scan all modules to see which ones cannot communicate, check related fault codes, and test the differential module’s power, grounds, connectors, and network wiring using vehicle-specific service information. These checks help distinguish a wiring or network issue from a module fault before parts are replaced.

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Commonly Asked Questions

Does U0135 prove that the front differential control module is bad?

No. It indicates lost communication with that module. Power, ground, connector, wiring, or network problems can cause the same condition and should be checked before condemning the module.

Can I keep driving with this code?

That depends on the vehicle’s behavior and warnings. If it drives normally, arrange diagnosis promptly. Stop safely and seek assistance if drive behavior becomes unpredictable or a serious driveline or stability warning appears.

Why might there be no warning light or noticeable symptom?

The communication loss may be intermittent, or the affected function may not be needed under current driving conditions. A scan can still show the fault even when no symptom is obvious.

What should be checked before replacing a module?

A technician should review codes from all modules and check the relevant power, grounds, connectors, wiring, and communication network according to vehicle-specific service information.

Browse Available Code Guides

Previous and next available guides in database record order, across makes. Adjacent entries may share a code number and do not necessarily describe related faults.