Land Rover Range Rover Electronic Arir Suspension Rover Manual
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EAS - System Information Document © Rover Group 1998Page 11 of 32 RANGE ROVER CLASSIC SERVICE cont. ECU SELF DIAGNOSTIC LIMITATIONS The ECU may seem to misdiagnose a problem. This is due mainly to the limited number of inputs on which to base decisions. Because of the similarity of symptoms, multiple faults may be registered where only one is actually present. The following is a summary of alternative interpretations of a registered fault message: • Height sensor above or below has no alternatives. • Engine speed has no alternatives. • Road speed has no alternatives. • Front valve stuck open has no alternatives. • Rear valve stuck open has no alternatives. • Inlet valve stuck open has no alternatives. • Pressure switch on may be confused with inlet valve stuck closed or rear valve stuck closed. • Pressure switch stuck off may be confused with compressor failure or air supply leak. • Compressor failure may be confused with inlet valve stuck closed, exhaust valve stuck open or air supply leak. These four messages may be set interchangeably. • Front valve stuck closed may be confused with inlet valve stuck closed or exhaust valve stuck closed. • Rear valve stuck closed may be confused with inlet valve stuck closed or exhaust valve stuck closed. • Exhaust valve stuck closed may be confused with front valve stuck closed or rear valve stuck closed. Pay particular attention to sensor outputs over the vehicle’s range of suspension travel (See TIB 60/05/95). Perform System Test. TestBook will generally find the problem. The diagnostics following will be divided into two categories: FAULT MESSAGE DIAGNOSIS – This will give an explanation of what sets the message and some suggested TIB references as well as information relevant to the message. SYMPTOM DIAGNOSIS – To be used in case of the absence of fault messages or warning lamp illumination. Probable causes of symptoms will be provided.
EAS - System Information Document © Rover Group 1998Page 12 of 32 RANGE ROVER CLASSIC SERVICE cont. FAULT MESSAGE DIAGNOSIS ANY HEIGHT SENSOR ABOVE OR BELOW LIMIT This is set when a specific sensor is detected operating outside of its allowable operating range. Select Dynamic Tests/Heights and Valves to view sensor readings. Also refer to TIBs 60/04/95/US and 60/05/95/US to help locate the defective component. Verify sensor readings over the entire range of suspension travel. The lower limit is 40 bit counts and the upper limit is 225 bit counts. ANY CORNER VALVE STUCK OPEN, CLOSED, OR CANNOT LOWER This is set when the system is unable to make a sensor’s output reach its demanded value. Select Air Suspension/Valve Cycling to determine whether the corner flagged will move up or down. Don’t forget to run the compressor for a few minutes to build air pressure in the reservoir. If the corner moves, refer to TIBs 60/09/95/US and 60/05/95/US to locate the defective component. If it does not move, refer to TIB 60/09/94/US to determine specifically which component is at fault. It is highly unlikely that both the valve block and valve driver could fail at the same time. Early VIN vehicles may not have valve blocks and valve drivers available separately. INLET VALVE STUCK CLOSED OR EXHAUST VALVE STUCK OPEN This is set when the system is unable to make more than one sensor’s output reach its demanded value. An air leak or a weak compressor could also set this. Select Dynamic Tests/Heights and Valves to determine the cause. Also, refer to TIB 60/02/95/US when operating in cold climates. Refer to TIB 60/09/94/US for more details. PRESSURE SWITCH STUCK ON (CLOSED) OR OFF (OPEN) These messages are set when the air usage does not correspond to the implied air pressure. Remember that the system has no way of determining the actual air pressure. Perform a Pressure Switch Test using TestBook and LRT-60-001 pressure gauge to verify switch operation. NOTE: Later version reservoirs will require adapter LRT-60-006 because of different sized drain plug. The results should be open to closed at 10 BAR (140 psi) and closed to open at 8.5 BAR. (125 psi) It should take roughly six minutes for an empty system to reach 10 BAR (140 psi) with the driver’s door open. Refer to TIB 60/07/94/US. ENGINE SPEED OR VEHICLE SPEED A signal from the alternator (phase tap) is used to determine engine speed, while the signal from the vehicle speed sensor is used to determine road speed. The fault messages are set when the ECU sees values for either speed above a set limit. Use any icon under Dynamic Tests to locate the problem. Verify that the latest speed sensor is installed (see TIB P93//68- 003). AIR SUPPLY LEAK OR COMPRESSOR FAILURE This fault is set when the system is unable to bring more than one sensor to its target and the pressure switch remained off during that time. Use Health Check and Dynamic Tests to locate the cause.
EAS - System Information Document © Rover Group 1998Page 13 of 32 RANGE ROVER CLASSIC SERVICE cont. SYMPTOM DIAGNOSIS THE SYSTEM WILL NOT INITIALIZE TestBook establishes communications during power-up of the ECU, pressing the initialize button momentarily interrupts the power allowing TestBook to start communications. Check that the delay relay clicks when the initialize button is pressed. If it does not, check the power and ground to the relay. If the relay is functioning properly, the power supply to the VCSI “brick” must be confirmed. Current flow should be approximately 40 mA when checked at the battery positive terminal. Confirm that TestBook is functional by trying it on another vehicle. THE COMPRESSOR DOES NOT RUN All of the following must be true for the compressor to run: • The engine speed must achieve 500 rpm and then cannot drop below 150 rpm. • The pressure switch must be open. • The thermal switch must be off (closed, grounded). • The exhaust valve must be closed, no height changes taking place. • The compressor relay must be closed and the 30-amp ‘maxifuse’ must be intact. SYSTEM DOES NOT BUILD PRESSURE FAST ENOUGH Connect TestBook. Select Air Suspension and perform a Health Check. Use the pressure switch test to validate all system components. A rough measure is zero to 10 BAR (140psi) in six minutes with a door open, vehicle speed equal to zero. Check for leaks from the exhaust port when the compressor is running. This indicates a problem with the diaphragm valve or solenoid. VEHICLE LEANS TO ONE SIDE Using Dynamic Tests, verify that each sensor can meet its target value. Inspect the sensors for mechanical damage and range with TIB 60/05/95/US. The vehicle should not drop more than 15mm (0.6 in.) per day due to leakage. THE COMPRESSOR CYCLES ON AND OFF FREQUENTLY Leave door open to prevent height changes. The compressor should then run until the pressure switch closes or the thermal switch trips. Run a pressure switch test using TestBook if the compressor runs too long. Inspect height sensor readings for range and stability per TIB 60/05/95/US. THE COMPRESSOR TURNED OFF AND WILL NOT RUN FOR SEVERAL MINUTES The compressor has probably overheated. If the thermal trip (127º C) occurs, there will be a three-minute cool down period during which compressor operation will not occur. This cool down period can be overridden by turning the ignition off and allowing the system to power down. THE VEHICLE IS SLOW TO LOWER Perform a Health Check. There is either a restriction in a hose or the inlet valve is stuck open during the exhaust period. Use Valve Cycling and listen for valve clicking. NOTE: There is no way to determine that the ECU is in a “cooling period.” The Compressor and Speeds screen on TestBook can only monitor the active state of the thermal switch. Refer to Connector C333 detail. COMPRESSOR NOT RUNNING WHEN “ON” Under Dynamic Tests/Compressor and Speeds, the compressor does not follow the operation indicated by TestBook directly. Specifically, the compressor will stop for system leveling even though TestBook indicates that it is still ON. To correctly use this screen, leave a door open to prevent leveling (exhausting). Other problems could result from compressor or associated wiring. Trouble shoot with the ETM. Use Valve Cycling function on TestBook.
EAS - System Information Document © Rover Group 1998Page 14 of 32 SERVICE (NEW RANGE ROVER) The most useful tool available to repair any EAS problem is TestBook. The system is only trying to make four sensors stay within a defined error range. Each rear sensor individually should be within 2 bits of the other. The same holds true for the front axle sensors. The TestBook routine for New Range Rover starts out by checking for system fault messages before allowing access to the main menu. For this reason, it is useful at times to select the vehicle model as Range Rover Classic in order to use the main menu (e.g., to clear the Corrupt Sensor Data fault message). The TestBook menu offers the following utilities: CALIBRATE–This routine should only be performed when a height sensor or ECU has been replaced. DEFLATE–Used to depressurize the system, this function will not work if the inlet or exhaust solenoids have failed. DYNAMIC TESTS–Provides real-time serial data for each subroutine. • Heights and Valves–Height sensors data. • Switches–All input switch data. • Compressor and Speeds-Input and output data. HEALTH CHECK–Read faults, performs complete system functionality test including pressure switch. TRANSPORT MODE–Electronically locks the suspension into Access profile for speeds below 25 mph. HIGH LOCK MODE–Electronically locks the suspension into High profile for speeds below 35 mph. VALVE CYCLING–Used to manually open valves and run the compressor. SYSTEM CALIBRATION In an effort to adjust for variations between sensors and their locations on the chassis, it is necessary to calibrate the system. Unlike Classic, this vehicle calibrates the chassis to the axles. Special blocks (LRT-60-003), which place the chassis at a known height above the axles where the corresponding sensor bit counts are recorded, accomplish this. It may be necessary at times to select the vehicle model as Range Rover Classic to enable direct access to air suspension main menu. This is very useful when difficulties are experienced when trying to clear a Corrupt Sensor Data fault message. However, do not attempt to calibrate a late model Range Rover using a Classic routine. Refer to TIB 60/02/94/US. At the start of the routine, all existing sensor values are overwritten with known default values. This way a consistent starting point is used for all vehicles. If the calibration routine is not successfully completed, the system will set a fault message for Corrupt Sensor Data. This means that the system is operating with default sensor data. This message can only be cleared by successfully completing a calibration. During the calibration routine both the pressure switch and the thermal switch are ignored. Complete the routine as quickly as possible in order to avoid potential compressor damage. When calibration is complete, there should be 100 ±4mm (4.0 ± .2 in.) between the front bump stop stud and the front axle pad, while the rear, measured similarly, should be 105 ±4mm (4.2± .2 in.) standard ride height.
EAS - System Information Document © Rover Group 1998Page 15 of 32 NEW RANGE ROVER SERVICE cont. SUMMARY OF AVAILABLE FAULT MESSAGES FRONT LEFT SENSOR OUT OF RANGEFRONT RIGHT SENSOR OUT OF RANGE REAR LEFT SENSOR OUT OF RANGEREAR RIGHT SENSOR OUT OF RANGE ENGINE SPEEDVEHICLE SPEED PRESSURE SWITCH STUCK ONPRESSURE SWITCH STUCK OFF COMPRESSOR FAILURECORRUPT SENSOR DATA CANNOT LOWER FRONT RIGHT CANNOT LOWER FRONT LEFT CANNOT LOWER REAR LEFTCANNOT LOWER REAR RIGHT FRONT RIGHT VALVE STUCK OPENFRONT LEFT VALVE STUCK OPEN REAR RIGHT VALVE STUCK OPENREAR LEFT VALVE STUCK OPEN EXHAUST VALVE STUCK OPENINLET VALVE STUCK OPEN FRONT RIGHT VALVE STUCK CLOSEDFRONT LEFT VALVE STUCK CLOSED REAR RIGHT VALVE STUCK CLOSEDREAR LEFT VALVE STUCK CLOSED EXHAUST VALVE STUCK CLOSEDINLET VALVE STUCK CLOSED ECU SELF DIAGNOSTIC LIMITATIONS The ECU may seem to misdiagnose a problem. This is due to the limited number of inputs on which to base decisions. Because of the similarity of symptoms, multiple faults may be registered where only one is actually present. The following is a summary of alternative interpretations of a registered fault message: • Height sensor above or below has no alternatives. • Engine speed has no alternatives. • Road speed has no alternatives. • Front valve stuck open has no alternatives. • Rear valve stuck open has no alternatives. • Inlet valve stuck open has no alternatives. • Pressure switch on may be confused with inlet valve stuck closed or rear valve stuck closed. • Pressure switch stuck off may be confused with compressor failure. • Compressor failure may be confused with inlet valve stuck closed, exhaust valve stuck open. • Front valve stuck closed may be confused with inlet valve stuck closed or exhaust valve stuck closed.
EAS - System Information Document © Rover Group 1998Page 16 of 32 NEW RANGE ROVER SERVICE cont. • Rear valve stuck closed may be confused with inlet valve stuck closed or exhaust valve stuck closed. • Exhaust valve stuck closed may be confused with front valve stuck closed or rear valve stuck closed. Pay particular attention to sensor outputs over the vehicle’s range of suspension travel (See TIB 60/05/95). Perform System Test. TestBook will generally find the problem. The diagnostics following will be broken up into two categories: FAULT MESSAGE DIAGNOSIS –This will give an explanation of what sets the message and some suggested TIB references as well as information relevant to the message. SYMPTOM DIAGNOSIS –To be used in case of the absence of fault messages or warning lamp illumination. Probable causes of symptoms will be provided.
EAS - System Information Document © Rover Group 1998Page 17 of 32 NEW RANGE ROVER SERVICE cont. FAULT MESSAGE DIAGNOSIS ANY HEIGHT SENSOR ABOVE OR BELOW LIMIT This is set when a specific sensor is detected operating outside of its allowable operating range. Select Dynamic Tests/Heights and Valves to view sensor readings (Use Range Rover Classic menu if necessary). Also refer to TIB 60/04/95/US to help locate the defective component. Verify sensor readings over the entire range of suspension travel. The lower limit is 40 bit counts and the upper limit is 225 bit counts. ANY CORNER VALVE STUCK OPEN, CLOSED, OR CANNOT LOWER Set when the system is unable to make a sensor’s output reach its demanded value. Select Air Suspension/Valve Cycling to determine whether the corner flagged will move up or down. Don’t forget to run the compressor for a few minutes to build air pressure in the reservoir. If the corner moves, refer to TIB 60/05/95/US to locate the defective component. If it does not move, refer to TIB 60/09/94/US to determine specifically which component is at fault. It is highly unlikely that both the valve block and valve driver could fail at the same time. INLET VALVE STUCK CLOSED OR EXHAUST VALVE STUCK OPEN This is set when the system is unable to make more than one sensor’s output reach its demanded value. An air leak or a weak compressor could also set this. Select Dynamic Tests/Heights and Valves to determine the cause. INLET VALVE STUCK OPEN OR EXHAUST VALVE STUCK CLOSED This is set when the system is unable to make more than one sensor’s output reach its demanded value. Select Dynamic Tests/Heights and Valves to determine the cause. If operating in cold climates, refer to TIB 60/02/95/US. PRESSURE SWITCH STUCK ON (CLOSED) OR OFF (OPEN) These messages are set when the air usage does not correspond to the implied air pressure. Remember that the system has no way of determining the actual air pressure. Perform a Pressure switch test using TestBook and LRT-60-001 pressure gauge to verify switch operation. NOTE: Later version reservoirs will require adapter LRT-60-006 because of different sized drain plug. The results should be open to closed at 10 BAR (140 psi) and closed to open at 8.5 BAR (125 psi). If the system is empty it should take roughly 7.5 minutes to reach 10 BAR (140 psi) with the driver’s door open. ENGINE SPEED OR VEHICLE SPEED These messages are set when the ECU sees values for either speed above a set limit (Vehicle speed 160 mph, engine speed 8,000 rpm). Use any icon under Dynamic Tests to locate the problem. COMPRESSOR FAILURE This message is set when the system is unable to bring more than one sensor to its target and the pressure switch remained off during that time. The system has no way of knowing if the compressor is operating. Use Health Check and Dynamic Tests to locate the cause.
EAS - System Information Document © Rover Group 1998Page 18 of 32 NEW RANGE ROVER SERVICE cont. SYMPTOM DIAGNOSIS THE SYSTEM WILL NOT INITIALIZE Verify that the delay relay is powering the system. This can be observed by watching the lamp of the unlatched inhibit switch. Turn the ignition on, but do not start the engine. The switch lamp should illuminate if the ECU has power at pin 1. If not, check fuses 24 and 44 in the engine compartment. The lamp should go out when the remote button on the TestBook lead is depressed. Also check the TestBook VCSI current for a current flow of approximately 40 mA at fuse F33. Confirm that TestBook is functional by trying it on another vehicle. THE COMPRESSOR DOES NOT RUN All of the following must be true for the compressor to run: • The engine speed must be greater than 500 rpm and then cannot drop below 150 rpm. • The pressure switch must be open. • The thermal switch must be off (closed, grounded). • The exhaust valve must be closed, no height changes taking place. • The compressor relay must be closed and the 30-amp ‘maxifuse’ MF2 must be intact. SYSTEM DOES NOT BUILD PRESSURE FAST ENOUGH Connect TestBook. Select Air Suspension and perform a Health Check. Use the pressure switch test to validate all system components. A rough measure is zero to 10 BAR (140 psi) in 7.5 minutes with any door or tailgate open, vehicle speed equal to zero. Check for leaks from the exhaust port when the compressor is running indicating a problem with the diaphragm valve or solenoid. VEHICLE LEANS TO ONE SIDE Using Dynamic Tests, verify that each sensor can meet its target value. Inspect the sensors for mechanical damage and range with TIB 60/05/95/US. The vehicle should not drop more than 15mm (.6 in.) per day due to leakage. THE COMPRESSOR CYCLES ON AND OFF FREQUENTLY Leave door or tailgate open to prevent height changes. The compressor should then run until the pressure switch closes or the thermal switch trips. Run a pressure switch test using TestBook if the compressor runs too long. Inspect sensor readings for range and stability with TIB 60/05/95/US. THE COMPRESSOR TURNED OFF AND WILL NOT RUN FOR SEVERAL MINUTES The compressor has probably overheated. If the thermal trip (127º C) occurs, there will be a three-minute cool down period during which compressor operation will not occur. This cool down period can be overridden by turning the ignition off and allowing the system to power down. THE COMPRESSOR IS NOISY Perform a system pressure test using TestBook to ensure that the compressor can build pressure properly. If the compressor is operating properly, check the compressor mounts. A new mounting system is currently under investigation. See TIB 60/06/95/US.
EAS - System Information Document © Rover Group 1998Page 19 of 32 NEW RANGE ROVER SERVICE cont. THE VEHICLE IS SLOW TO LOWER Inspect the exhaust filter for restriction. Perform a Health Check. There is either a restriction in a hose or the inlet valve is stuck open during the exhaust period. Use Valve Cycling and listen for valve clicking. NOTE: There is no way to determine that the ECU is in a “cooling period.” The Compressor and Speeds screen on TestBook can only monitor the active state of the thermal switch. Refer to Connector C151 detail. COMPRESSOR NOT RUNNING WHEN “ON” Under Dynamic Tests/Compressor and Speeds, the compressor does not follow the operation indicated by TestBook directly. Specifically, the compressor will stop for system leveling even though TestBook indicates that it is still ON. To correctly use this screen, leave a door or tailgate open to prevent leveling (exhausting). Other problems could result from compressor or associated wiring. Trouble shoot with the ETM. Use Valve Cycling function on TestBook.
EAS - System Information Document © Rover Group 1998Page 20 of 32 RANGE ROVER CLASSIC CONNECTOR DETAILS NOTE: Range Rover Classic connectors shown are for 1995 MY vehicles. Most descriptions and colors are the same for 1993 MY and 1994 MY, but connector numbers may differ. Refer to the ETM for clarification if required. C256 Up Switch PositionColorDescription 1. Red/BrownSwitch Illumination 2. BlackGround E201 3. Yellow/RedStatus Lamp Signal ECU pin 25 4. Yellow/BlueSwitch Common ECU pin 29 5. Yellow/BrownSwitch Signal to ECU pin 32 6. Blue/Lt GreenStatus Lamp Power F14 C257 Inhibit Switch PositionColorDescription 1. Yellow/SlateStatus Switch Signal ECU pin 15 2. Yellow/BlueSwitch Common ECU pin 29 3. BlackGround E201 4. -- 5. SlateStatus Lamp Power F14 6. Red/BrownSwitch Illumination C258 Down Switch PositionColorDescription 1. Red/BrownSwitch Illumination 2. BlackGround E201 3. Yellow/WhiteStatus Lamp Signal ECU pin 7 4. Yellow/BlueSwitch Common ECU pin 29 5. Yellow/OrangeSwitch Signal ECU pin 33 6. Lt GreenStatus Lamp Power F14