Suspension - Air Suspension Diagnostic Guidelines
No: 60/01/05/NAS
FGN LM204
Ref:
Issue: 1
Date: March 16, 2005
Air Suspension Diagnostic Guidelines
AFFECTED VEHICLE RANGE:
Range Rover (LM) All
SITUATION:
INCORRECTLY DIAGNOSED EAS SYSTEM FAULTS
The EAS control unit stores fault codes for numerous air suspension system component failures. In the majority of cases, changing the ECU will
re-activate the system and appear to have rectified the fault. However, the root cause of the problem may well be in a system component rather than
the ECU.
RESOLUTION:
FOLLOW RECOMMENDED DIAGNOSTIC PROCESS
Should a customer express concern regarding air suspension, refer to the Diagnostic Procedure detailed in this bulletin for correct system diagnosis
before changing the ECU. There are only four reasons for changing the Air Suspension ECU:
^ T4 Fault Code 52 (ECU Memory Fault)
^ T4 Fault Code 53 (ECU Fault)
^ T4 Fault Code 55 (ECU Calibration Fault)
^ Communications to the EAS ECU have failed.
Other faults are component-related and require system diagnosis and troubleshooting.
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PARTS INFORMATION
DDW WARRANTY CLAIMS:
DDW requires the use of causal part numbers. Labor only claims must show the causal part number with a quantity of zero.
REPAIR PROCEDURE
PRELIMINARY EAS SYSTEM EVALUATION
1. Determine if one of the following faults exists:
^ T4 Fault Code 52 (ECU Memory Fault)
^ T4 Fault Code 53 (ECU Fault)
^ T4 Fault Code 55 (ECU Calibration Fault)
^ Communications to the EAS ECU have failed.
NOTE:
Problems other than the communications fault and Codes 52, 53, and 55 are due to other components, wiring or air harness faults. Normal
fault diagnosis is required to determine component and harness faults.
CAUTION:
The solving of height sensor problems should always be accompanied by re-calibrating the vehicle trim heights.
2. If any other problem is diagnosed that appears to be ECU-related, identify the root cause in the system.
3. If one of the above faults is determined, go to the appropriate diagnostic section for that fault in this bulletin. Follow the procedures detailed
for the Fault Codes diagnosis before replacing the ECU.
T4 FAULT CODE 52 (ECU MEMORY FAULT)
1. Start T4 diagnostic session.
2. Enter Vehicle VIN and follow on-screen instructions.
3. Select 'Vehicle Configuration'.
4. Select 'Reconfigure ECUs'.
NOTE:
GTR lookup sequence is as follows: GTR Home > NAS > Service Information/LM Range Rover/2005 > Electrical Library > "Range
Rover 2002MY ON Electrical Library" > Bookmark "CONNECTOR" > Select the connector number link referenced in the text of this
TIB.
NOTE:
GTR provides the Right Hand Drive location of the ECU. The correct Left Hand Drive ECU location is "Behind the RH side of facia"
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CAUTION:
All terminals should be seated to the same level. A fully seated terminal will be located within 1 mm of being flush with the connector
surface.
5. If the fault code is not cleared perform the following:
^ Check EAS ECU connection C0867 for loose connectors or corrosion.
^ Re-secure or clean connection as necessary.
^ Check connection C2030 for loose connection or corrosion.
^ Examine the connector mating-face to verify all terminals are fully seated.
^ Confirm all terminals are fully seated by pushing each wire from the back of the connector into the connector housing. Any unseated
terminals will "click" home.
^ Check battery ground connections C0821 and C0553.
^ Clean connections as necessary and verify that connectors C0821 and C0553 are tightened to 10 Nm (7 lbf ft).
6. Determine if fault codes have been cleared as follows:
^ Start T4 diagnostic session.
^ Enter Vehicle VIN and follow on-screen instructions.
^ Select 'Vehicle Configuration'.
^ Select 'Reconfigure ECUs'.
7. If the fault code is cleared the failure has been fixed.
8. If the fault code is not cleared replace the EAS ECU.
T4 FAULT CODE 53 (ECU FAULT)
1. Refer to GTR section 60.50.04 and replace the EAS ECU.
T4 FAULT CODE 55 (ECU CALIBRATION FAULT)
1. Refer to GTR section 60.50.04 and replace the EAS ECU.
COMMUNICATIONS TO THE EAS ECU HAVE FAILED.
1. Verify that the T4 connector is correctly coupled to the vehicle diagnostic connector.
NOTE:
GTR lookup sequence is as follows: GTR Home > NAS > Service Information/LM Range Rover/2005 > Electrical Library > "Range
Rover 2002MY ON Electrical Library" > Bookmark "CONNECTOR" > Select the connector number link referenced in the text of this
TIB.
2. Check for good battery ground connection on pins 4 and 5 of the diagnostic connector (C0040).
3. Check for battery power at pin 1 (ignition positive) and pin 16 (battery positive) of the diagnostic connector (C0040).
4. If no power is evident, check fuse 5 (ignition -7.5 amp) and fuse 15 (battery feed -5 amp) at the passenger fuse box.
5. If the checked fuses are open/blown, replace fuses as necessary.
6. Ensure that no short circuit is present and T4 connections are good.
7. Perform the following check for battery power at EAS ECU:
^ Check fuse 57 (15 amp) in passenger fuse box.
^ If fuse 57 is open/blown check connector C0582, cavity 3, at the top of the passenger fuse box for loose connections or corrosion.
Re-secure or clean terminals as necessary.
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^ Check connectors C0867 and C2030 at the EAS ECU for loose connections or corrosion. Re-secure or clean terminals as necessary.
^ Install Connectors C0867 and C2030 and test for communication.
^ If there is no communication, check for battery power at connector C2030, cavity 10.
^ If there is no power at cavity 10, check fuse 57 (battery feed 15 amp) in passenger fuse box.
8. Check for battery ground at EAS ECU, connector C2030, cavity 5.
9. If there is no ground at C2030 cavity 5 perform the following:
^ Check harness run for continuity.
^ Check for proper connections at ground header K109, connector C0285, and ground eyelet C0553.
10. Check for continuity between connector C0867, cavity 2 and instrument pack connector C0234, cavity 8.
11. If there is no continuity perform the following:
^ Check harness run for continuity.
^ Check for proper connections at sealed joints X18827 and X18836.
12. Check for continuity between connector C0867, cavity 20 and instrument pack connector C0234, cavity 9.
13. If there is no continuity perform the following:
^ Check harness run for continuity.
^ Check for proper connections at sealed joints X18826 and X18835.
14. Check for continuity between pin 8 of diagnostic connector (C0040) and pin 1 of instrument pack connector (C0233).
15. If there is no continuity perform the following:
^ Check harness run for continuity.
^ Check for proper connections at sealed joint X183.
16. Check instrument pack for faults and repair as necessary.
17. If any repairs have been completed, check for communication.
18. If the instrument pack is functional and the checks and connection validations have not resolved the issue, replace the EAS ECU with a new
