U2504

Code

LAND ROVER U — Network/User

Token missing from ABS for adaptive cruise control

Brand: LAND ROVER

Type: U — Network/User

Views: UK: 25 EN: 42 RU: 29

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

ABS module failed to provide authentication token
Loss of CAN communication between ABS and ACC/control modules
Corrupted or missing module software/coding
Battery voltage issues or intermittent power/ground to ABS module
Connector damage, corrosion, or broken wiring on CAN/ABS power circuits
Aftermarket module/ECU replacement without proper pairing or security programming

Symptoms

Adaptive cruise control inoperative or disabled with warning message
ABS/ESC warning lamp illuminated or stored ABS-related codes
Loss of vehicle stability or traction control functions when ACC attempts to engage
Communication-related warnings on instrument cluster (e.g., ECU communication fault)
Possible intermittent operation of ACC or repeated failures after repair attempts

What to check

Record freeze frame and full UDS/CAN fault memory from ABS, ACC and gateway modules using an OEM-capable scan tool
Check battery voltage at rest and during cranking; ensure stable supply (12.4–12.8 V nominal for testing)
Visually inspect ABS connector(s) and wiring for corrosion, damage or loose pins
Scan for other U-codes (CAN bus loss) that indicate wider network issues
Verify module part number, software and calibration levels against factory data to see if reflash/pairing is required
Check for aftermarket equipment that may interfere with CAN/security systems

Signal parameters

CAN high/low differential voltage: ~2.5 V idle (dominant/recessive behavior); check for expected voltage swings when modules communicate
Typical ABS CAN message IDs and expected update frequency (use OEM data): ABS wheel speed and status messages should update regularly when vehicle is on
Battery voltage at ABS connector (reference expected 11–15 V during operations)
Ground continuity from ABS module to chassis ground (
Check for error counters or bus-off frames on CAN controller (scan-tool/live data)

Diagnostic algorithm

Capture and record all U-codes from ABS, ACC, gateway and related modules with an OEM scan tool. Note freeze-frame and last-wake events.
Verify battery state of charge and health. Recharge or connect stable power supply and re-check codes.
Inspect ABS module connectors, harness and ground. Repair any damaged wiring or corroded pins.
Check CAN bus integrity: measure CAN high/low voltages, look for shorts to supply or ground, and verify termination resistances (~60 ohms across CAN H/L).
If network and power are good, compare ABS module software/calibration and security status to factory requirements. If module was recently replaced or updated, confirm pairing/authorization was completed.
Attempt to clear codes and cycle ignition to see if the token is reissued. If intermittent, try to reproduce under consistent conditions.
If OEM data indicates required reprogramming or security provisioning, perform module reflash/pairing using manufacturer tools (dealer-level security authentication may be required).
If reprogramming does not restore token or communication, consider ABS module replacement and ensure new module is properly configured and paired.
After repair, clear codes, perform required adaptations/calibrations and road-test to confirm ACC and ABS functions are restored.

Likely causes

ABS module software or calibration requires reprogramming or replacement
CAN bus wiring fault, poor termination, or intermittent connection
Vehicle security/authentication pairing not completed after module replacement
Low battery voltage or poor ground affecting module startup and token generation
ABS module hardware fault preventing token generation

Fault status

⚠️ Status

ABS failed to provide required security token for Adaptive Cruise Control; ACC functionality inhibited until ABS authentication and communication are restored.

🔴 Repair difficulty: Hard

⏱️ Diagnostic time: 1.0 - 3.0 hours

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