Repair Procedure
REPAIR PROCEDURECLEARING DIAGNOSTIC TROUBLE CODES (DTC) *AND REPROGRAMMING ECU*
CAUTION:
All diagnosis should be conducted with the engine running or with a suitable battery charger connected. The air compressor demands a high current draw and performance will decrease with reductions in voltage. The air compressor will not operate when voltage is below 9VDC.
*CAUTION:
A Midtronics PSC-550 Vehicle Power Supply must be connected to the vehicle battery during diagnosis.*
1. *Connect the Midtronics PSC-550 power supply to the vehicle battery.*
NOTE:
Before attempting to resolve any air suspension problem, the electronic air suspension DTCs stored in the electronic control unit (ECU) must be recorded.
2. Connect diagnostic equipment to the vehicle and load disc "Range Rover 20" or later.
3. Enter the vehicle VIN and follow the on-screen instructions.
4. Select 'Vehicle Configuration'.
5. Record the stored electronic air suspension DTCs.
6. Clear all DTCs
7. Select Reconfigure ECUs.
8. Follow the on-screen instructions *to reconfigure the ECU*, but do not replace the ECU if instructed to do so.
9. *Exit the diagnostic session.
10. Perform a road test and when completed activate EAS system using the vehicle height selection switch in both directions to fully exercise the system to fully raised and fully lowered positions.
11. Reconnect diagnostic equipment and check for DTC's.
12. If no DTCs are present the repair is complete.*
NOTE:
The 'OVERHEAT' or 'COMPRESSOR COOLING' information panel displayed when operating the air compressor, is not a defect, but is to inform the technician that the air compressor has reached its maximum specified operating temperature or maximum operating time and is now in its cooling cycle. When the air compressor temperature reduces sufficiently the information panel will return to 'OK' and the air compressor will begin normal operation again.
13. *If DTCS are stored*, first check for air leaks at all pipe connections.
NOTE:
Under no circumstances should the air compressor's clam-shell casing be opened by the technician. This will result in a rejection of the warranty claim. There are NO serviceable items within the air compressor clam-shell casing.
NOTE:
It is recommended that a 12 Volt test lamp is used rather than a multi-meter during some testing because the exhaust valve is driven by a 400 Hz pulse width modulation (PWM) voltage which may cause the reading on a multi-meter to be confusing. Depending on the multi-meter used, the values may flash intermittently or may show no reading. The test lamp may not be as bright as expected or may flicker. This is also due to the PWM voltage and is not a problem.
14. *If any DTCs are stored*, perform the applicable Diagnostic Procedure below depending on the DTC displayed.
DIAGNOSTIC TROUBLE CODES
NOTE:
Most of the problems indicated by the listed trouble codes could have causes other than an actual air compressor failure. The diagnostic procedures provided for specific codes guide the user through the diagnosis for individual DTCs to identify the actual cause.
^ Other problems that occur should focus on other component failures (wiring harness/air harness failures), as the cause. Normal problem resolution methods should be used for component/harness failures.
^ The solving of height sensor problems must be accompanied by re-calibrating the vehicle trim heights.
15. Refer to the table for the twenty Diagnostic Trouble Codes (DTC) that could indicate that the air suspension supply unit may require replacement.
DTC 07, DTC 23
Diagnostic Trouble Code 07 (Exhaust Valve Defect)
Hardware defect on exhaust valve or wiring harness defect.
Diagnostic Trouble Code 23 (Reservoir/Exhaust Valve Supply Defect)
Hardware defect on exhaust valve supply or wiring harness defect.
NOTE:
The exhaust valve and reservoir valve share a common power supply.
1. Open the exhaust valve using T4/RDS air suspension diagnostics Force Outputs.
2. Refer to GTR Electrical Library Section C0873, connect a 12 volt test lamp across pins 2 and 12 and check for voltage at the harness side of the main air compressor connector.
3. If there is NO voltage present, check the wiring and air suspension ECU.
4. If voltage is present, verify that the resistance of the exhaust valve at the air compressor side of the main air compressor connector C0873 across pins 2 and 12 is between 13 and 19 Ohms at 20°C (68°F).
5. If the resistance is out of range, refer to GTR Section 60.50.10 and replace the air compressor.
6. If the resistance is in range, use T4/RDS air suspension diagnostics to verify that the reservoir pressure is greater than 7 bar.
NOTE:
The reservoir pressure should decrease significantly (>1 bar/20s) in the next step.
7. Open the exhaust valve and reservoir valve using the Force Outputs option and monitor the reservoir pressure.
8. If the pressure does NOT drop significantly, refer to GTR section 60.50.10 and replace the air compressor.
9. If DTC 23 was the fault and the compressor replacement in step 8 does NOT resolve the problem, perform the following:
^ Refer to GTR section 60.50.11 and change the reservoir valve assembly.
^ Install the original air compressor.
10. Clear the DTCs using T4/RDS.
11. Check for error-free air suspension operation and any new DTCs.
12. If the previous steps have NOT resolved the issue, replace the air compressor and repeat tests.
DTC 08, DTC 24
Diagnostic Trouble Code 08 (High Pressure Exhaust Valve Defect)
Hardware defect on high pressure exhaust valve or wiring harness defect.
Diagnostic Trouble Code 24 (High Pressure Exhaust Valve Supply Defect)
Hardware defect on high pressure exhaust valve supply or wiring harness defect.
1. Open the exhaust valve using T4/RDS air suspension diagnostics Force Outputs.
2. Refer to GTR Electrical Library Section C0873. Connect a 12 volt test lamp across pins 5 and 11 and check for voltage at the harness side of the main air compressor connector.
3. If there is no voltage present, check the wiring and air suspension ECU.
4. If voltage is present, measure the the resistance of the high pressure exhaust valve at the air compressor side of the main air compressor connector C0873 across pins 5 and 11 is between 4.1 and 6.1 Ohms at 20°C (68°F).
5. If the resistance is out of range, refer to GTR Section 60.50.10 and replace the air compressor.
6. If the resistance is in range, clear the DTCs using T4/RDS.
7. Check for error-free air suspension operation and any new DTCs.
8. If steps 1-7 have not resolved the issue, refer to GTR section 60.50.10 and perform the following:
^ Replace the air compressor.
^ Repeat the tests to verify correct operation.
DTC 36
Diagnostic Trouble Code 36 (Compressor Temperature Sensor)
Hardware defect on compressor temperature sensor or wiring harness defect.
NOTE:
This test should be completed with the ignition on and the air compressor nominally at room temperature. The vehicle must not have been parked outside in below freezing temperatures for a long period of time and, if possible, the air compressor should not have been allowed to run immediately prior to the test.
1. Verify that the ignition is in the ON position and that the compressor is at room temperature.
2. Refer to GTR Range Rover 2002MY Electrical Library Workshop Manual Section C0873 Pump-Air suspension and check with a multi meter that the voltage at the air compressor connector plug C0873 across output pins 4 and 6 with the connector coupled is between 0.3V and 4.8V.
NOTE:
The voltage decreases as the temperature of the air compressor increases. If the air compressor is below freezing, the temperature sensor voltage may be close to 5V. This is not a defect. Running the air compressor to raise the temperature and a second check of the voltage should provide a lower reading.
3. If the voltage is outside the specified range and the air compressor is nominally at room temperature, check wiring and air suspension ECU.
4. When the voltage is correct, verify that the resistance is < 0.5 Ohms between a the ECU connector C0867 terminal 31 (black/red wire) and the temperature sensor wiring of the air compressor harness connector C0873 terminal six (black/blue wire).
5. If the resistance is >05 Ohms, repair the wiring as necessary.
6. Check that the resistance is <0.5 Ohms between the ECU connector C0867, terminal 49 (black wire) and the temperature sensor wiring of the air compressor harness connector C0873, terminal four (black wire).
7. If the resistance is >0.5 Ohms, repair the wiring as necessary.
8. Clear the DTCs using T4/RDS
9. Check for error-free air suspension operation and any new DTCs.
10. If the steps 1 through 9 have not resolved the issue, refer to GTR section 60.50.10 and replace the air compressor.
11. Repeat the tests to verify the repair.
DTC 101, DTC 116
Diagnostic Trouble Code 101 (No or Slow Movement When Lifting)
The ECU is attempting to increase the height of the vehicle and has detected that the height is increasing very slowly or not increasing at all.
Diagnostic Trouble Code 116 (Reservoir Pressure Static When Filling)
The ECU is attempting to fill the reservoir and the measured reservoir pressure is not increasing.
NOTE:
It is normal for the measured pressure in the reservoir to reduce by up to 0.5 bar when the air compressor is switched off.
1. Fill the air reservoir using T4/RDS air suspension diagnostics.
2. Verify that the maximum reservoir pressure is between 11.6 and 12.0 bar.
NOTE:
The running air compressor will be audible in the rear loadspace with the spare wheel cover and spare wheel removed.
3. If the air compressor cannot be switched on and off, refer to the Range Rover 2002 MY Electrical Library Workshop Manual Section Fuse Details - Rear Fusebox. Check, and if required, replace the air compressor 50A fuse.
4. If the air compressor still cannot be switched on and off perform the following:
^ Check, and if indicated, repair the wiring harness.
^ Check, and if indicated, repair the air compressor relay located in the rear fusebox.
5. If the reservoir pressure is within the 11.6 and 12.0 bar range when the air compressor is operating correctly, the air compressor is working error-free.
6. If the reservoir pressure is NOT within the 11.6 and 12.0 bar range, check the air lines for leakage and repair as necessary.
7. If no leak is found, replace the air reservoir solenoid valve assembly.
8. Fill the air reservoir using T4/RDS and check the maximum reservoir pressure.
9. If the reservoir pressure is within the 11.6 and 12.0 bar range, the air compressor is working error-free.
10. If the reservoir pressure is NOT within the 11.6 and 12.0 bar range, refer to GTR Section 60.50.10 and replace the air compressor.
11. Fill the air reservoir using T4/RDS and check the maximum reservoir pressure.
12. If the reservoir pressure is within the 11.6 and 12.0 bar range, the system is working error-free.
13. If the reservoir pressure is NOT within the 11.6 and 12.0 bar range, refer to Technical Bulletin 60/03/05/NAS and replace the air reservoir pressure sensor and install the original compressor.
14. Using the Force Outputs option, open the exhaust valve and reservoir valve and verify that the reservoir pressure decreases significantly (>1 bar/20s).
15. If the pressure does not decrease at >1 bar/20s, replace the air reservoir solenoid valve assembly.
16. If an aluminum reservoir is installed, perform the following:
^ Check the area of reservoir pipe between the valve and the reservoir body for white corrosion.
^ If any white corrosion is visible in the area of the connector where it is screwed into the reservoir, check for leakages in this area.
^ If it is not possible to stop the leakage, refer to GTR section 60.50.03 and replace the reservoir assembly.
17. Clear any DTCs using T4/RDS.
18. Verify error-free air suspension operation and determine if there are any new DTCs.
DTC 103, DTC 104, DTC 105, DTC 106, DTC 107, DTC 108
NOTE:
With the listed DTCs, the ECU is attempting to change the height of the vehicle (lifting or lowering) and it has detected that the height change is taking too long.
^ The ECU estimates how much "energy" is supplied to the corner (i.e. amount of air added or removed) and flags a defect if the estimated value becomes too large.
^ The ECU functions as a sophisticated timer, with the time allowed for the height change based on distance to be moved and expected rate of air flow (i.e. whether the vehicle is lifting or lowering, whether a lift uses the reservoir as well as the air compressor, reservoir pressure).
^ The timers (energy monitors) are split to allow faster detection under certain circumstances but in essence they are checking the same behavior.
1. Fill the air reservoir useing T4IRDS air suspension diagnostics.
2. Verify that the maximum reservoir pressure is between 11.6 and 12.0 bar.
NOTE:
The running air compressor will be audible in the rear loadspace with the spare wheel cover and spare wheel removed.
3. If the air compressor cannot be switched on and off, refer to the Range Rover 2002 MY Electrical Library Workshop Manual Section Fuse Details - Rear Fusebox. Check, and if required, replace the air compressor 50A fuse.
4. If the air compressor still cannot be switched on and off perform the following:
^ Check and if indicated repair the wiring harness
^ Check and if indicated repair the air compressor relay located in the rear fusebox.
5. If the reservoir pressure is within the 11.6 and 12.0 bar range when the air compressor is operating correctly, the air compressor is working error-free.
6. If the reservoir pressure is NOT within the 11.6 and 12.0 bar range, check the air lines for leakage and repair as necessary.
7. If no leak is found, replace the air reservoir solenoid valve assembly.
8. Fill the air reservoir using T4/RDS and check the maximum reservoir pressure.
9. If the reservoir pressure is within the 11.6 and 12.0 bar range, the air compressor is working error-free.
10. If the reservoir pressure is NOT within the 11.6 and 12.0 bar range, refer to GTR Section 60.50.10 and replace the air compressor.
11. Fill the air reservoir using T4/RDS and check the maximum reservoir pressure.
12. If the reservoir pressure is within the 11.6 and 12.0 bar range, the system is working error-free.
13. If the air release is audible but the reservoir pressure is NOT within the 11.6 and 12.0 bar range, refer to Technical Bulletin 60/03/05/NAS and replace the air reservoir pressure sensor.
NOTE:
The reservoir pressure should decrease significantly (>1 bar/20s) in the next step.
14. Open the exhaust valve and reservoir valve using the "Forced Option" feature of T4/RDS.
15. If the pressure indicated by T4 does not drop but the air release is heard, refer to Technical Bulletin 60/03/05/NAS and replace the air reservoir pressure sensor.
16. If the pressure indicated by T4 does not drop and the air release is NOT heard replace the air reservoir solenoid valve.
17. Clear any DTCs using T4/RDS.
18. Verify error-free air suspension operation and determine if there are any new DTCs.
DTC 102, DTC 119
Diagnostic Trouble Code 102 (No or Slow Movement When Lowering)
The ECU is attempting to decrease the height of the vehicle and has detected that the height is decreasing very slowly or not decreasing at all.
Diagnostic Trouble Code 119 (Reservoir Pressure Static When Exhaust Required)
The ECU is attempting to vent the reservoir and the measured reservoir pressure is not decreasing.
1. Check air suspension lines for any blockage or leakage and repair as necessary.
2. Verify that there is air pressure in the reservoir.
3. Check using T4/RDS that the air compressor exhaust valve is opening as follows:
^ Open the exhaust valve and reservoir valve using the Force Outputs option,.
^ Monitor the reservoir pressure and determine if the reservoir pressure decreases significantly (>1 bar/20s).
4. If the reservoir pressure does not decrease, refer to GTR section 60.50.10 and replace the air compressor.
5. Clear any DTCs using T4/RDS.
6. Verify error-free air suspension operation and determine if there are any new DTCs.
DTC 109, DTC 117, DTC 118
Diagnostic Trouble Code 109 (Height Change In Wrong Direction When Lifting)
The ECU is attempting to increase the height of the vehicle and has detected that the height is decreasing rather than increasing.
Diagnostic Trouble Code 117 (Reservoir Pressure Drops Initially When Filling)
Diagnostic Trouble Code 118 (Reservoir Pressure Drops When Filling)
The ECU is attempting to fill the reservoir and the measured reservoir pressure is decreasing.
NOTE:
Under normal circumstances, the reservoir pressure is expected to drop in the first few seconds after the reservoir valve is opened as the pressures in the reservoir and common gallery equalize. During this time, the threshold to detect a defect is set larger so that normal operation won't be detected as a defect. However, a very big pressure drop will set the DTC 117. After a few seconds the reservoir pressure is expected to rise so the threshold to detect the defect is decreased to increase the sensitivity of this diagnostic. Hence a very big air leak will set DTC 117 while a smaller leak will set DTC 118.
1. Check the air reservoir for visible damage.
2. If the reservoir is damaged refer to GTR section 60.50.03 and replace the reservoir.
3. If an aluminum reservoir is installed, perform the following:
^ Check the area of reservoir pipe between the valve and the reservoir body for white corrosion.
^ If any white corrosion is visible in the area of the connector where it is screwed into the reservoir, check for leakages in this area.
^ If it is not possible to stop the leakage refer to GTR section 60.50.03 and replace reservoir assembly.
4. Check the reservoir pipe between the reservoir and the solenoid valve for damage.
5. If the pipe is damaged, replace with a new pipe.
6. Check the solenoid valve for leakage and repair as necessary.
7. Check the air pressure relief valve for air leakage. (Figure 1)
8. If a leak is detected, replace the inline pressure relief valve.
9. Verify that there is pressure in the reservoir.
10. Determine if the air compressor exhaust valve is stuck open using T4/RDS diagnostics as follows:
^ Open the reservoir valve only using the Force Outputs option with all other valves closed.
^ Monitor that the reservoir pressure does NOT decrease significantly (<0.1bar/20s).
11. If the reservoir pressure drops significantly, refer to GTR Section 60.50.10 and replace the air compressor.
12. Clear any DTCs using T4/RDS.
13. Verify error-free air suspension operation and determine if there are any new DTCs.
DTC 111
Diagnostic Trouble Code 111 (Air compressor Temperature Rises When Air compressor Inactive) The ECU is not attempting to run the air compressor but the air compressor temperature is still increasing. This means that the air compressor probably is running, though not under the control of the ECU.
1. Verify that the latest level of air suspension software applicable to this vehicle is uploaded into the ECU.
NOTE:
The running air compressor will be audible in the rear loadspace with the spare wheel cover and spare wheel removed.
2. Determine using T4/RDS diagnostics if the air compressor can be switched on and off.
3. If the air compressor cannot be switched on and off, perform the following:
^ Refer to Range Rover 2002MY Electrical Library Workshop Manual Section Fuse Details - Rear Fusebox.
^ Inspect and if indicated replace the air compressor 50A fuse.
4. Operate the air suspension switch output using T4/RDS diagnostics and monitor the air compressor relay response.
5. If the relay does not follow the switching commands, replace the air compressor relay located in the rear fuse box.
6. If the air compressor still cannot be switched on and off refer to GTR Section 60.50.10 and replace the air compressor.
7. Clear any DTCs using T4/RDS.
8. Verify error-free air suspension operation and determine if there are any new DTCs.
DTC 112
Diagnostic Trouble Code 112 (Air compressor Temperature Static When Air compressor Is Active)
The ECU is attempting to run the air compressor but the air compressor temperature is not increasing. This means that the air compressor is probably not running.
1. Verify that the latest version of air suspension software applicable to this vehicle is uploaded into the ECU.
NOTE:
The running air compressor will be audible in the rear loadspace with the spare wheel cover and spare wheel removed. The relay must follow the switching commands from T4.
2. Switch the air compressor on/off using T4/RDS diagnostics and monitor the output voltage of the air compressor relay.
3. If the air compressor cannot be switched on and off, perform the following:
^ Refer to Range Rover 2002MY Electrical Library Workshop Manual Section Fuse Details - Rear Fusebox.
^ Inspect and if indicated replace the air compressor 50A fuse.
4. If the fuse replacement does not correct the issue, check and if indicated replace the air compressor relay located in the rear fusebox.
5. If the new relay does not resolve the problem, install the original relay.
6. Check the ECU output wiring for damage.
7. If damage is determined, repair or replace the wiring as required.
8. Check the air compressor wiring for damage or connector terminal back-outs.
9. If damage or connector back-outs are determined, repair or replace the wiring as required.
10. Check the temperature sensor wiring for damage or connector terminal back-outs.
11. If damage or connector back-outs are determined, repair or replace the wiring as required.
NOTE:
The voltage measured decreases as the temperature of the air compressor increases. If the air compressor temperature is below freezing, the temperature sensor voltage may be close to 5V. This is not a defect. Run the air compressor and re-check the voltage.
12. Using a volt meter perform the following:
^ Check that the voltage is between approximately 0.3V and 4.8V across pins 4 and 6 at the air compressor connector plug C0873 with the connector coupled.
^ If the voltage is outside the 0.3V and 4.8V range, check the wiring and connector for terminal back-outs.
^ Check that the voltage is between approximately 0.3V and 4.8V across pins 31 (black/red wire) and 49 (black wire) at the air suspension ECU connector C0867 with the connector coupled.
^ If the voltage is outside this range, check the wiring and connector for terminal back-outs.
NOTE:
The temperature sensor is not a serviceable item.
13. If the voltage is within range, refer to GTR Section 60.50.10 and replace the air compressor.
14. Determine if the air compressor can be switched on and off using T4/RDS diagnostics.
15. If the air compressor cannot be switched on and off refer to GTR section 60.50.10 and replace the air compressor and air compressor relay.
16. Clear any DTCs using T4/RDS.
17. Verify error-free air suspension operation and determine if there are any new DTCs.