U045C

Code

Generic U — Network/User

Invalid Data Received From Power Steering Control Module “B”

Brand: Generic

Type: U — Network/User

Views: UK: 27 EN: 39 RU: 23

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Page language: EN

Causes

Faulty Power Steering Control Module (PSCM) “B”.
Corroded, loose, damaged or improperly seated connector at the PSCM.
Damaged or shorted CAN bus wiring (CAN High/Low) between PSCM and network.
Poor ground or battery supply to PSCM causing corrupt data or resets.
Missing or mismatched software/calibration in PSCM after module replacement or update.
Intermittent electrical interference or EMC issues on the vehicle data bus.

Symptoms

Steering system warning lamp or message displayed on instrument cluster.
Reduced or inconsistent electric power steering assist (may go to limp/backup).
Intermittent steering assist loss or jerky steering behavior.
Multiple network/U codes present in the scan tool for steering or gateway.
Possible disabling of advanced driver aids that rely on steering data.

What to check

Scan network for U-codes and related codes (gateway, ABS, EPS/PSCM, BCM) and read freeze frame data.
Check battery state of charge and measure supply voltage to PSCM while cranking and under load.
Visually inspect PSCM connector and wiring for damage, corrosion, water intrusion, or loose pins.
Verify CAN bus termination (approx. 60 Ω across CAN H-L with ignition off) and inspect for shorts to battery or ground.
Measure CAN H and CAN L idle voltages with key on (recessive ~2.5 V each) and check dominant levels when active.
Check for software or calibration updates and confirm module part number and programming level match vehicle spec.

Signal parameters

CAN message ID(s) used by PSCM “B” (monitor for expected IDs and presence on bus).
Message period/frequency and jitter (expected periodic interval vs observed).
Message length (DLC) and payload structure (expected bytes vs corrupted values).
Sequence/counter bits and CRC/checksum fields to detect framing or integrity errors.
Timestamp of last valid message and age (time since last valid frame).
CAN High and CAN Low idle voltages (~2.5 V recessive), dominant voltages (~CANH ~3.5 V, CANL ~1.5 V) and differential level when active.

Diagnostic algorithm

Retrieve and record all stored/active U- and related DTCs and freeze frame data. Note occurrence conditions.
Check battery voltage and charging system; ensure battery is charged and stable during tests.
Inspect PSCM connector and wiring harness visually; repair any corrosion, bent pins, or damage. Reseat connector.
With a diagnostic tool, monitor CAN traffic: confirm PSCM messages are present, check message frequency, counters and CRC. Note missing or malformed frames.
Measure CAN H/L voltages and check termination resistance across CANH-L with ignition off. Repair wiring faults if readings are out of range.
Wiggle test harness and connectors while monitoring messages to find intermittent opens/shorts.
If wiring and bus integrity are good, verify module part number and software calibration. Reflash or reprogram PSCM if an update or mismatch is found and recommended by manufacturer.
If faults persist after wiring and software verification, consider replacing PSCM “B”. After any repair, clear codes and perform a road test while monitoring CAN traffic and steering behavior.
If replacing the module, follow manufacturer provisioning (coding, programming, security access) and recheck for reoccurrence of U045C.

Likely causes

Connector/cable issue at PSCM (pin corrosion, broken wire, poor contact).
CAN bus wiring short or open between PSCM and gateway/ECU.
PSCM hardware failure or internal memory/data corruption.
Low battery or intermittent supply/ground to PSCM.
Software/calibration mismatch after service or module replacement.

Fault status

⚠️ Status

Invalid or corrupt data received from Power Steering Control Module "B" on the vehicle data bus. Check PSCM communication, wiring, power/ground, and module software.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1-4 hours

Repair manuals