CAN network

U0131 — Lost Communication with Power Steering Control Module

Severity: medium Drive with care, to a shop

What U0131 means

U0131 means other control units stopped receiving messages from the power steering control module (PSCM) over the CAN bus. The module normally exchanges data with the rest of the vehicle constantly and uses it to decide how much steering assist to give. If the link is lost because of a wiring fault, poor power or ground, or a failed module, assist may shut down or be reduced.

Symptoms

  • Power steering or steering warning light on
  • Heavier steering effort, especially at low speed
  • Power steering assist lost completely or intermittently
  • PSCM does not respond or responds intermittently to a scan tool
  • Other warning lights on at the same time
  • Functions that depend on the module unavailable

Possible causes

  1. Open or shorted CAN bus lines (most likely)
  2. Loss of power or ground at the PSCM, such as a blown fuse or poor connection
  3. Corroded or damaged connectors and terminals
  4. Chafed or damaged wiring harness
  5. Failed power steering control module
  6. Another faulty module loading down the CAN bus
  7. Steering rack actuator problem

How to diagnose

  1. Scan all modules and note which ones still communicate and which do not
  2. Check fuses and relays in the PSCM power supply circuit
  3. Inspect the PSCM connector and harness for corrosion, moisture, chafing and backed-out terminals
  4. Check supply voltage and ground integrity at the module connector
  5. Measure resistance between CAN High and CAN Low at the diagnostic connector (about 60 ohms is normal) and check bus voltages
  6. Test the CAN wires for opens and shorts to ground or power
  7. If another module is suspected, disconnect modules one at a time, only following a documented procedure
  8. If power, ground and bus are good, test the PSCM and replace and program it if needed

Common fixes

  • Replace blown fuses and restore power and ground to the module
  • Repair or replace damaged CAN wiring and connectors
  • Clean corroded contacts and secure loose terminals
  • Replace the power steering control module and program or code it
  • Replace a faulty module that is loading the bus

Questions and answers

What does U0131 mean?

It means the CAN network lost communication with the power steering control module. The module itself may be fine, since wiring, power or ground faults are common causes.

Can I drive with U0131?

Only carefully and not far, for example to a shop. The steering can become very heavy, especially during low-speed maneuvers.

How do I clear U0131?

Clearing the code only helps temporarily. First find the cause by checking module power, ground and the CAN lines, then clear the code with a scan tool.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.