U04BD

Code

Generic U — Network/User

Invalid Data Received From Park Lock/Pawl Control Module

Brand: Generic

Type: U — Network/User

Views: UK: 17 EN: 40 RU: 26

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Page language: EN

Malfunction Indicator Lamp (MIL) or network warning lamp illuminated
Shift interlock or park lock may not operate correctly; vehicle may not exit park
Transmission may be inhibited from shifting or engine start may be disabled
Intermittent message or network-related warnings on scan tool
No response from park lock module when attempting diagnostics

Read and record all U-codes and related freeze frame/capture data with a capable scan tool
Check battery voltage and charging system (perform tests with engine on and off)
Visually inspect connectors and wiring for the Park Lock/Pawl module for corrosion, bent pins, or damage
Check chassis and module grounds that serve the park lock control circuit
Scan the vehicle network for bus errors, data message frequency, and message CRC/checksum failures
Attempt to communicate directly with the Park Lock/Pawl module using a diagnostic tool

Presence of Park Lock/Pawl module CAN/LIN message (expected message ID / PGN on vehicle network)
Message frequency (expected periodic rate; e.g., messages present at a steady rate versus intermittent)
Message length and payload format (no unexpected length changes)
Checksum/CRC or message integrity flag OK
Bus voltage levels during message transmission (CAN high/low differential and supply)
No repeated CAN error frames or bus-off state

Retrieve freeze frame, full DTC list and any manufacturer-specific data. Note conditions when the fault set.
Verify battery voltage and charging system; recharge or test battery if low. Retest after stable voltage is confirmed.
Clear the code and attempt to reproduce. If intermittent, record when it returns and under what conditions.
Visually inspect the Park Lock/Pawl module connector and wiring harness for damage, corrosion, or pin issues. Repair as needed.
Backprobe or scope the communication lines at the module and at the gateway/ECU to confirm message presence, voltage levels, and absence of excessive noise.
Use a scan tool to view the module's messages on the bus (message ID, frequency, and data content). Look for invalid data fields or checksum failures.
Inspect related grounds and power feeds to the module. Repair poor ground connections or wiring faults.
If wiring and power are good, check for software/firmware mismatch. Confirm module part number and calibration; reprogram or update to factory software if required.
If message is absent or consistently invalid after software check, consider module replacement. Program and configure replacement module per manufacturer procedure.
After repairs, clear codes, perform targeted tests (operate park lock, shift out of park, start inhibit checks) and road/test as required to confirm the issue is resolved.

Loose or corroded connector at the Park Lock/Pawl module
Open/short in the module communication wires (CAN/LIN) between the module and gateway/ECU
Module swapped/replaced without proper programming or with incompatible software
Battery voltage low or poor ground affecting message integrity
Failed Park Lock/Pawl module electronics (internal memory, transceiver)