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DTC codes / U04xx · Invalid data received from a module / U042C

U042CInvalid Data Received From Chassis Control Module B

U042C means the module that coordinates chassis systems received invalid or missing data from Chassis Control Module B over the vehicle's communication network. The computer detected a message that was absent, corrupted, or outside the expected range, so it flagged the data source as unreliable.

SystemNetwork
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaInvalid data received from a module

Symptoms you may notice

  • Illumination of the antilock brake system (ABS), traction control, or stability control warning lights
  • A warning message on the driver information display indicating a chassis system fault
  • Reduced or disabled stability control and traction control functions
  • Unexpected activation of a chassis warning chime or limp-home mode
  • Often no symptoms besides the warning light, with normal braking and steering feel

Common causes, most likely first

  1. A weak or failing battery, or poor battery terminal connections, causing low-voltage communication errors
  2. Corroded, loose, or damaged wiring and connectors in the chassis control module B circuit
  3. A faulty chassis control module B that is unable to transmit valid data
  4. A software or calibration issue in the chassis control module B or the receiving module
  5. A failed or intermittent network communication bus (CAN) segment affecting chassis modules
  6. Water intrusion or physical damage to the chassis control module B or its harness
  7. A charging system fault that produces unstable voltage during engine operation

How to diagnose and fix it

  1. Perform a battery and charging system test, including load testing and checking terminal cleanliness and tightness
  2. Inspect the chassis control module B connectors and harness for corrosion, chafing, or loose pins
  3. Use a scan tool to read all modules for communication codes and check for related U-codes that point to a shared bus fault
  4. Check for technical service bulletins (TSBs) or software updates for the chassis control module B and the receiving module
  5. Measure network bus voltage and resistance at the diagnostic connector to confirm bus integrity
  6. If wiring and power are good, substitute a known-good chassis control module B or perform module reprogramming as directed by the manufacturer
  7. Clear codes and perform a road test to verify the fault does not return

Chassis Module B Data Faults Often Misread

  • A low or unstable battery voltage is one of the most common triggers for U042C, and technicians often replace modules before checking the battery and charging system.
  • The code does not always mean Chassis Control Module B has failed; it can be set by a wiring fault or a problem in another module on the same communication bus.
  • Some vehicles require a relearn or calibration procedure after battery replacement or module service, and skipping it can leave a persistent U042C.
  • Corrosion inside a connector that looks fine from the outside can interrupt data transmission intermittently, especially after rain or a car wash.
  • A generic scan tool may not display chassis module data accurately, so manufacturer-specific software is often needed to confirm the fault.

Can I keep driving with U042C?

You can usually drive the vehicle, but stability control and traction control may be disabled, so reduce speed and avoid slippery or emergency maneuvers. If the ABS warning light is also on, have the system inspected promptly because braking assist features may be affected.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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