U0131: Lost Communication With Power Steering Control Module (PSCM)
May cause heavy or lost power steering assist; can affect vehicle handling, especially at low speeds.
Overview
U0131 OBD‑II code indicates loss of communication between vehicle network (CAN bus) and the Power Steering Control Module leading to power steering assist issues.
Common Symptoms
- Power steering warning light illuminated
- Heavier steering effort required
- Loss of power steering assist
- Intermittent or no communication with PSCM on scan tool
Most Common Causes
CAN bus interruption prevents proper data exchange with PSCM.
Blown fuse, bad ground, or wiring fault can remove electrical supply to module.
Module internal failure or corrupted software leading to communication failure.
Physical connector damage often disrupts signal and voltage integrity.
Diagnostic Steps
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Connect professional OBD‑II scanner and confirm U0131 and related codes.Expected: U0131 present; attempt to communicate with PSCM.Interpretation: If PSCM responds to scan tool, fault may be intermittent or memory only; if no access, issue is active.
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Check fuses and relays supplying power to PSCM.Expected: All relevant fuses intact and functional.Interpretation: A blown fuse indicates power supply issue; replace and retest.
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Inspect power and ground circuits at PSCM with a multimeter.Expected: Battery voltage at power pins and solid ground readings.Interpretation: No voltage or poor ground indicates wiring/fuse issue.
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Visually inspect CAN high and low wiring and connectors to PSCM.Expected: No broken, corroded, or damaged wires/connectors.Interpretation: Damaged wiring can cause communication failure.
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Measure CAN bus voltage on CAN H and CAN L with ignition on.Expected: Approximately nominal differential voltages per manufacturer spec.Interpretation: Incorrect readings indicate bus fault.
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If wiring and power are good, consider PSCM replacement or software update.Expected: Communication restored after replacement or update.Interpretation: Restored communication confirms module failure or firmware issue.
Repair Solutions
Fuse and wiring repairs are lower cost and should be addressed first.
Costs vary based on location and extent of harness damage.
PSCM replacement may require dealer programming.
Common Misdiagnoses
Avoid these common diagnostic mistakes:
- Assuming PSCM is faulty without verifying power/ground and CAN connectivity
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