Suspension - EAS Won't Maintain Ride Height When Cold
No: 64/02/03/NASRef:
*Issue: 2
Date: 7 September 2005*
Air Suspension Ride Height Problems
AFFECTED VEHICLE RANGE:
*Range Rover (LM) 2003 2005 Model Years*
SITUATION:
AIR SUSPENSION UNABLE TO MAINTAIN TARGET HEIGHT IN COLD CONDITIONS
In temperatures below -20� C (-5� F) the air suspension system may encounter difficulties maintaining normal ride height. There are three possible causes:
^ The vehicle may lower onto the bump stops due to air leakage from the rear springs.
^ The pressure relief valve may be opening below the reservoir target pressure, causing an error in the air suspension ECU system.
^ Low battery charge (below 11 volts) may cause an error in the air suspension Electrical Control Unit (ECU). The error will be logged and will disable the air suspension system.
RESOLUTION:
VERIFY SPRING AND BATTERY CONDITION AND RECONFIGURE ECU
Where a complaint of ride height irregularities is confirmed, follow the rectification procedures outlined in this TIB to ensure installation of the latest configuration rear air springs, proper battery condition
and correct ECU programming.
PARTS INFORMATION:
WARRANTY CLAIMS
REPAIR PROCEDURE
CHECK REAR AIR SPRING SPECIFICATION
1. Raise the vehicle on lift.
2. Remove screw securing the rear air spring to the lower suspension arm.
3. Inspect the rear air spring boss.
4. If the markings are not visible (Figure 1), install screw securing the air spring to lower arm and tighten the screw to 7 Nm (5 lbf.ft.).
5. If markings are visible (Arrowed in Figure 2) refer to RAVE section 64.21.01 and replace the rear air spring assembly.
6. Repeat steps 2 to 5 for the alternate side.
CHECK BATTERY CONDITION
1. Check external condition of the battery including battery connections for damage.
2. Switch on headlights for 20 seconds, then switch ignition off.
CAUTION:
Failure to wait two minutes before disconnecting the battery will damage the navigation computer. The RAVE Workshop Manual General Information, Electrical Precautions, Battery disconnection contains detailed information.
3. Refer to RAVE and follow all precautions. Wait for a further two minutes to permit the NAV computer to power down and to remove the battery surface charge.
4. Release the battery positive terminal insulation cover.
5. Release the battery negative terminal insulation cover.
6. Disconnect the battery negative lead.
7. Ensure both battery connections are clean.
CAUTION:
Do not connect the tester to any other circuits or to the chassis.
8. Connect the Midtronics battery tester to the battery.
9. Use the arrows to scroll to the number that matches the battery, Cold Cranking Amps (CCA) written on the battery label.
CAUTION: Make sure the entered CCA number is to the same standard as the tester is as the tester is calibrated to.
10. Press "test" button and follow the on-screen instructions:
11. Perform "Action" indicated in table above depending on tester reading.
12. Connect battery.
CONFIGURE AIR SUSPENSION ECU
1. Connect TestBook/T4 to the vehicle and load special TestBook/T4 disc DJL0DASZ (Air Suspension Diagnostics). The disc is included with this TIB distribution
CAUTION:
During the following TestBook/T4 process several commands are to be ignored:
^ The air suspension ECU is not to be replaced.
^ The battery is not to be disconnected.
^ Personalization is not to be applied to air suspension ECU when asked.
^ Height calibration is not to be selected when asked.
2. Follow the on-screen instructions as detailed in the following flow table:
CAUTION:
Only use T4/TestBook disc DJL0DASZ to carry out this procedure and ensure all the instructions are carried out as detailed below. Make sure to retain the disc for future use.
3. To reconfigure the Air Suspension ECU select "System Diagnostics"
4. Select "Air Suspension" on the screen shown.
5. Follow general guidance on displayed screen and when ready, press the "Continue" button to proceed.
6. Review the ECU details and when ready, press the "Continue" button to proceed.
7. Select "Vehicle Maintenance" from the screen shown to the right
8. Select "ECU Renewal" from the screen shown to the right
9. When ready, press the "Continue" button to proceed on the screen shown to the right.
CAUTION:
Do NOT replace the Air Suspension ECU and do NOT disconnect battery.
10. Press the "Continue" button to proceed on the screen shown to the right
11. Select the "No" button at this point to proceed on the screen shown to the right.
12. Ensure ignition is ON and then press the "Continue" button on the screen shown to the right to proceed
CAUTION:
The revised coding will be operable once the ignition cycle described in this screen has been performed. Ensure the time delays are followed.
NOTE:
Once the procedure is complete, the screen to the right is displayed.
13. Select "Continue" to proceed.
14. Select "Exit" button on the screen shown to the right to proceed.
NOTE:
When the procedure is complete, this screen appears.
15. Press the "Continue" button to proceed.
16. Select "Real Time Display" from the screen on
the right.
17. Select "Reservoir Parameters" from the screen on the right.
NOTE:
The screen shown to the left will then be displayed. This screen gives general information on the Real Time Display selected.
18. When ready, press the "Continue" button to proceed.
19. Verify the "Target Reservoir Pressure" displays 10.7 bar and the "Minimum Reservoir Pressure" displays 8.0 bar.
20. When ready, press the "Continue" button to complete the procedure
21. Return to the "Diagnostic System" and disconnect TestBook/T4 from the vehicle.
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