Suspension Control: Overview Lexus RX II facelift

SYSTEM DESCRIPTION

1. AIR SUSPENSION SYSTEM DESCRIPTION The suspension control ECU operates the compressor & motor with the dryer and uses the solenoid valves to control the vehicle height by analyzing the information based on the switches, sensors and input signals. Through the 4 height control sensors, the suspension control ECU detects the changes in the vehicle height that results from the number of occupants or the amount of the load. Then, the suspension control ECU controls the height control solenoid valves and the compressor & motor with the dryer in order to automatically adjust the vehicle height to a constant (normal) vehicle height. Furthermore, three vehicle heights can be selected by operating the height control switch: HI, Normal and LO. When the engine is shut-off, the vehicle height can be lower than the LO vehicle height by operating the access mode switch. In the case such as when the vehicle is jacked up, the auto leveling function is prohibited by operating the height control OFF switch.

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1. TEST MODE PROCEDURE (USING SST CHECK WIRE) HINT: When entering the test mode, the suspension control ECU sets all the test DTCs first. After completing the input signal operation for each inspection item, the DTCs that are judged normal by the suspension control ECU will be erased. The DTCs for other inspection items may not be erased when only a certain signal is inspected. When the test mode returns back to the normal mode, all the test DTCs will be erased. Procedure for Test Mode. Make sure that the ignition switch is off. Set each of the check items in the table below to the condition in Operation (A). Using SST(s), connect the terminals TS and CG of DLC3. SST 09843-18040 Turn the ignition switch to the ON position. Check that the height control OFF indicator light comes on and goes off at 0.125 second intervals. (4 Hz) HINT: If the height control OFF indicator light does not blink, inspect the height control OFF indicator light circuit or the TS terminal circuit. TROUBLE AREA SPECIFICATION Trouble Area See procedure Height control off indicator light circuit «HEIGHT CONTROL OFF INDICATOR LIGHT CIRCUIT»(ref-235991-S27313604592006062900000) TS terminal circuit «TS TERMINAL CIRCUIT»(ref-235991-S18568409712006062900000) Set checking each items to the condition in Operation (B). HINT: When checking each item, the height control OFF indicator light should come on for 1 sec. then continue blinking. There is no input signal order. Test mode table: TEST MODE TABLE Check Item Operation (A) Operation (B) Stop light switch signal OFF (Brake pedal not depressed) ON (Brake pedal depressed) Right rear speed sensor signal Vehicle speed below 20 km/h (12 mph) Vehicle speed 20 km/h (12 mph) or higher Left rear speed sensor signal Vehicle speed below 20 km/h (12 mph) Vehicle speed 20 km/h (12 mph) or higher Height control switch signal Neutral position Press the height control switch "UP" first and then press "DOWN" Height control OFF switch signal OFF (Height control OFF indicator light is OFF) ON to OFF (Height control OFF switch pushed in 2 times.) Crankshaft position sensor signal Engine speed below 2,000 rpm Engine speed 2,000 rpm or higher Access mode switch signal OFF (Access mode switch not pushed in) ON to OFF (Access mode switch pushed in and released) Using the SST(s), connect the 3rd terminal of the SST to terminal TC in the DLC3. SST 09843-18040 Read the number of blinks of the height control OFF indicator light. HINT: As an example, the blinking patterns of a normal code and code 82 are shown in the illustration. If 2 or more malfunctions are indicated at the same time, the lowest numbered code is displayed first. When a DTC or normal code is not output, check the TC terminal circuit (See «TC AND CG TERMINAL CIRCUIT»(ref-235991-S18568409712006062900000) ). Check the malfunction using the code table below. Clear the test DTCs and return to normal mode. HINT: After repairing the malfunctions, clear the test DTC. Turn the ignition switch off. Disconnect the SST(s) from the terminals of DLC3. SST 09843-18040 Turn the ignition switch to the ON position.
2. TEST MODE PROCEDURE (INTELLIGENT TESTER) HINT: When entering the test mode, the suspension control ECU sets all the test DTCs first. After completing the input signal operation for each inspection item, the DTCs that are determined normal by the suspension control ECU will be erased. The DTCs for other inspection items may not be erased when only a certain signal is inspected. When the test mode returns back to the normal mode, all the test DTCs will be erased. Procedure for Test Mode. Make sure that the ignition switch is OFF. Set each of the check items to the condition in Operation (A) in the test mode table. Connect the intelligent tester to DLC3. Turn the ignition switch to the ON position. Select the SIGNAL CHECK mode on the intelligent tester. Set each of the check items to the condition in Operation (B) in the test mode table. HINT: In step (6), all signals can be checked together. Read the DTCs by following the prompts on the tester screen. HINT: Refer to the intelligent tester operator's manual for further details. After completing the input signal check, disconnect the tester and turn the ignition switch off. DTC of Air Suspension System test mode function: If a malfunction code is displayed during the test mode DTC check, check the circuit listed for that code. For details of each code, refer to the "See procedure" under respective "DTC No." in the chart. DTC CHART DTC No. (See procedure) Detection Item Trouble Area «C1782/82»(ref-235991-S05799832132006062900000) Stop light switch circuit malfunction Stop light switch assembly Stop light switch circuit Suspension control ECU «C1784/84»(ref-235991-S37744601412006062900000) Right rear speed sensor circuit malfunction Right rear speed sensor Right rear speed sensor circuit Skid control ECU (Brake actuator assembly) Suspension control ECU «C1785/85»(ref-235991-S37744601412006062900000) Left rear speed sensor circuit malfunction Left rear speed sensor Left rear speed sensor circuit Skid control ECU (Brake actuator assembly) Suspension control ECU «C1786/86»(ref-235991-S35522125732006062900000) Height control switch circuit malfunction Height control switch Height control switch circuit Suspension control ECU «C1788/88»(ref-235991-S31443534832006062900000) Height control OFF switch circuit malfunction Height control OFF switch Height control OFF switch circuit Suspension control ECU «C1797/97»(ref-235991-S32983642772006062900000) Crankshaft position sensor circuit malfunction Crankshaft position sensor Crankshaft position sensor circuit ECM Suspension control ECU
3. ADJUST VEHICLE HEIGHT (WHEN USING INTELLIGENT TESTER) HINT: Leave the driver's seat window open to make height control operation easier. Start the engine. Change the height control switch to the "N" position. Check that the blinking for the "N" light in the combination meter is on. Push the access mode switch to the off position. Stop the engine and turn the ignition switch OFF. HINT: Refer to the illustration. VEHICLE HEIGHT CHART Front Measured height B minus A Rear Measured height D minus C A: Ground clearance of lower front suspension arm No. 2 bush set bolt center. B: Ground clearance of front wheel center. C: Ground clearance of strut rod set bolt center. D: Ground clearance of rear wheel center. If the value of the vehicle height is not within the range of the standard value, note the value measured and proceed to the following step. Standard value table SENSOR CIRCUIT SPECIFICATION 4WD 2WD 112 +- 10 mm (4.406 +- 0.393 in.) 117 +- 10 mm (4.602 +- 0.393 in.) 36 +- 10 mm (1.421 +- 0.393 in.) 41 +- 10 mm (1.618 +- 0.393 in.) HINT: The difference between the right and the left sides should be less than 10 mm (0.39 in.). NOTE: In the case where the difference between the value of the vehicle height and standard value exceeds 80 mm (3.15 in.), this check cannot be performed by using the intelligent tester. In order to perform the check with the intelligent tester, adjust the difference below 80 mm (3.15 in.) without using the intelligent tester. Check the height control sensor sub-assembly (See «DTC C1711/11 Front Height Control Sensor RH Circuit Malfunction: DTC C1712/12 Front Height Control Sensor LH Circuit Malfunction: DTC C1713/13 Right Rear Height Control Sensor Circuit: DTC C1714/14 Left Rear Height Control Sensor Circuit»(ref-235991-S34981980232006062900000) ). Connect the intelligent tester to DLC3. Turn the ignition switch to the ON position. Perform the height offset procedure from the AIRSUS menu. Start the engine. Change the height control switch to the "HI" position and check that the blinking for the "HI" light on the meter has been changed to the illuminating. Change the height control switch to the "N" position again and get out of the vehicle immediately while the "N" light is blinking. NOTE: Be sure to get out of the vehicle while the light is blinking as the height will be changed and the value will not be measured properly if you fail to do so. Turn the ignition switch to the OFF position from outside of the vehicle after the "N" light comes on. NOTE: Do not touch the vehicle as its height may be changed. Check the vehicle height again to confirm the value of the vehicle height is within the range of the standard values.
4. ADJUST VEHICLE HEIGHT (WHEN NOT USING INTELLIGENT TESTER) Start the engine. Change the height control switch to the "N" position. Check that the blinking for the "N" light on the meter has been changed to the illuminating. Stop the engine and turn the ignition switch OFF. Check the vehicle height (calculated value). HINT: Leave the driver's seat window open to make height control operation easier. A: Ground clearance of lower suspension arm No. 2 bush set bolt center. B: Ground clearance of front wheel center. C: Ground clearance of strut rod set bolt center. D: Ground clearance of rear wheel center. If the value of the vehicle height is not within the range of the standard value, note the value measured and proceed to the following step. Standard value table SENSOR CIRCUIT SPECIFICATION 4WD 2WD 112 +- 10 mm (4.406 +- 0.393 in.) 117 +- 10 mm (4.602 +- 0.393 in.) 36 +- 10 mm (1.421 +- 0.393 in.) 41 +- 10 mm (1.618 +- 0.393 in.) HINT: Difference between the right and the left sides should be less than 10 mm (0.39 in.). Adjust the front vehicle height control sensor links. NOTE: Adjust the link of which the value for the vehicle height control is most beyond the range of the standard value first. If the values of the front vehicle height and the rear vehicle height are the same, adjust the front vehicle height control sensor link first. Loosen the nut and adjust the link position by moving it up and down along the bracket's hole on the vehicle. HINT: The vehicle height will be changed by approx. 5 mm (0.19 in.) when changing the link by approx. 1 mm (0.04 in.) Tighten the nut on the vehicle height control sensor link. Torque: 5.4 N*m (55 kgf*cm, 48 in.*lbf) Adjust the rear vehicle height control sensor links. Loosen the 2 lock-nuts on the vehicle height control sensor link and turn the link to adjust its length. HINT: Lengthen the link to raise the vehicle height. Shorten the link to lower the vehicle height. 2WD: The vehicle height will be changed be approx. 8 mm (0.31 in.) when turning the rear vehicle height control sensor link around once. 4WD: The vehicle height will be changed by approx. 3 mm (0.12 in.) when turning the rear vehicle height control sensor link around once. Check if the vehicle height control sensor link dimension (A) shown in the illustration is shorter than the standard value. Standard length: 18.0 mm (0.708 in.) or less Tighten the 2 lock-nuts on the vehicle height control sensor link. Torque: 5.4 N*m (55 kgf*cm, 48 in.*lbf) Check the vehicle height again to confirm the value of the vehicle height is within the range of the standard value. Adjust the headlight aim only (See «ADJUSTMENT»(ref-236032-S11580202892006062900000) ).

DESCRIPTION

The height control sensor sub-assembly controls the resistance value by following changes in vehicle height. The suspension control ECU detects the change in vehicle height from the transformed voltage. The suspension control ECU outputs a constant voltage of 5 V to the SHB terminal of the height control sensor sub-assembly. In the height control sensor the voltage is changed due to the resistance. The changed voltage is output from the SHFR terminal of the height control sensor sub-assembly to suspension control ECU, thus the vehicle height is detected.

HINT

1. If DTC C1711/11, C1712/12, C1713/13 or C1714/14 is output, the vehicle height control is suspended. Height control OFF switch on the combination meter assembly comes on and the vehicle height indicator "N" comes on or blink.
2. If the normal signal is output from the height control sensor sub-assembly while suspending the vehicle height control, the vehicle height control is resumed. The operation is also resumed when the ignition switch is turned off once, then turned on again.

DTC CHART

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HINT

Proceed to troubleshooting following the flow chart, regardless of whether or not DTCs C1711/11, C1712/ 12, C1713/13 or C1714/14 are displayed.

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1. RECONFIRM DTC Check DTCs (See «DTC CHECK / CLEAR»(ref-235991-S34224761592006062900000) ). Confirm if DTC C1761/61 and/or C1774/74 is recorded. OK: DTC C1761/61 and/or C1774/74 is not output. HINT: If either DTCC1761/61 (ECU malfunction) or C1774/ 74 (power source circuit) is displayed, carry out the necessary inspection. If they are output at the same time, carry out the necessary inspection for DTC C1774/74 first. NG: REPAIR CIRCUIT INDICATED BY OUTPUT CODE OK: Go to next step
2. READ VALUE OF INTELLIGENT TESTER HINT: When not using the intelligent tester, go to step 3. Connect the intelligent tester to the DLC3. Turn the ignition switch to the ON position, and push the intelligent tester main switch ON. Select the item below in the DATA LIST, and read its value displayed on the intelligent tester. AIRSUS DATA LIST ITEM CHART Item Normal condition FR HEIGHT Min.: -80 mm (-3.15 in.) Max.: 80 mm (3.15 in.) FL HEIGHT Min.: -80 mm (-3.15 in.) Max.: 80 mm (3.15 in.) RR HEIGHT Min.: -80 mm (-3.15 in.) Max.: 80 mm (3.15 in.) RL HEIGHT Min.: -80 mm (-3.15 in.) Max.: 80 mm (3.15 in.) Check the vehicle height value of each sensor while pressing the height control switch "UP" and "DOWN". OK: Vehicle height value changes NG: Go to step 3 OK: REPLACE SUSPENSION CONTROL ECU
3. CHECK HARNESS AND CONNECTOR (HEIGHT CONTROL SENSOR SUB-ASSEMBLY POWER SOURCE) Disconnect the height control sensor sub-assembly connector. Turn the ignition switch ON. Measure the voltage according to the values in the table below. Voltage (Front RH): (C1711/11) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition H13-1 (SHB) - H13-3 (SHG) 4.75 to 5.25 V Voltage: (Front LH): (C1712/12) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition H12-1 (SHG) - H12-3 (SHB) 4.75 to 5.25 V Voltage: (Rear RH): (C1713/13) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition H26-1 (SHG) - H26-3 (SHB) 4.75 to 5.25 V Voltage: (Rear LH): (C1714/14) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition H25-1 (SHB) - H25-3 (SHG) 4.75 to 5.25 V NG: Go to step 6 OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - HEIGHT CONTROL SENSOR SUB-ASSEMBLY) Disconnect the suspension control ECU S16 or S14 connector. Measure the resistance according to the values in the table below. Resistance (Front RH): (C1711/11) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S16-27 (SHFR) - H13-2 (SHFR) Below 1 ohms S16-27 (SHFR) - Body ground 10 kohms or higher Resistance: (Front LH): (C1712/12) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S16-28 (SHFL) - H12-2 (SHFL) Below 1 ohms S16-28 (SHFL) - Body ground 10 kohms or higher Resistance: (Rear RH): (C1713/13) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S14-24 (SHRR) - H26-2 (SHRR) Below 1 ohms S14-24 (SHRR) - Body ground 10 kohms or higher Resistance: (Rear LH): (C1714/14) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S14-23 (SHRL) - H25-2 (SHRL) Below 1 ohms S14-23 (SHRL) - Body ground 10 kohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. INSPECT HEIGHT CONTROL SENSOR SUB-ASSEMBLY HEIGHT CONTROL SENSOR FRONT RH: (C1711/11) Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 1 (SHB) - 3 (SHG) 4.3 +- 1.3 kohms 1 (SHB) - 2 (SHFR) Repeat about 0.4 to 3.9 kohms Result RESULT SPECIFICATION Result Proceed to OK A NG B HEIGHT CONTROL SENSOR FRONT LH: (C1712/12) Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 1 (SHG) - 3 (SHB) 4.3 +- 1.3 kohms 2 (SHFL) - 3 (SHB) Repeat about 0.4 to 3.9 kohms Result RESULT SPECIFICATION Result Proceed to OK A NG C HEIGHT CONTROL SENSOR REAR RH: (C1713/13) Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 1 (SHG) - 3 (SHB) 4.3 +- 1.3 kohms 2 (SHRR) - 3 (SHB) Repeat about 0.4 to 3.9 kohms Result RESULT SPECIFICATION Result Proceed to OK A NG D HEIGHT CONTROL SENSOR REAR LH: (C1714/14) Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 1 (SHB) - 3 (SHG) 4.3 +- 1.3 kohms 1 (SHB) - 2 (SHRL) Repeat about 0.4 to 3.9 kohms Result RESULT SPECIFICATION Result Proceed to OK A NG E B: REPLACE HEIGHT CONTROL SENSOR SUBASSEMBLY FRONT RH C: REPLACE HEIGHT CONTROL SENSOR SUBASSEMBLY FRONT LH D: REPLACE HEIGHT CONTROL SENSOR SUBASSEMBLY REAR RH E: REPLACE HEIGHT CONTROL SENSOR SUBASSEMBLY REAR LH A: REPLACE SUSPENSION CONTROL ECU
6. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU- HEIGHT CONTROL SENSOR SUB-ASSEMBLY) Disconnect the suspension control ECU connectors. Measure the resistance according to the values in the table below. Resistance (Front RH): (C1711/11) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S15-18 (SBR1) - H13-1 (SHB) Below 1 ohms S15-22 (SGR1) - H13-3 (SHG) Below 1 ohms S15-18 (SBR1) - Body ground 10 kohms or higher S15-22 (SGR1) - Body ground 10 kohms or higher Resistance: (Front LH): (C1712/12) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S15-21 (SBL1) - H12-3 (SHB) Below 1 ohms S16-25 (SGL1) - H12-1 (SHG) Below 1 ohms S15-21 (SBL1) - Body ground 10 kohms or higher S16-25 (SGL1) - Body ground 10 kohms or higher Resistance: (Rear RH): (C1713/13) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S14-19 (SGR2) - H26-1 (SHG) Below 1 ohms S14-20 (SBR2) - H26-3 (SHB) Below 1 ohms S14-19 (SGR2) - Body ground 10 kohms or higher S14-20 (SBR2) - Body ground 10 kohms or higher Resistance: (Rear LH): (C1714/14) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S14-21 (SGL2) - H25-3 (SHG) Below 1 ohms S14-22 (SBL2) - H25-1 (SHB) Below 1 ohms S14-21 (SGL2) - Body ground 10 kohms or higher S14-22 (SBL2) - Body ground 10 kohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
7. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - HEIGHT CONTROL SENSOR SUB-ASSEMBLY) Disconnect the suspension control ECU S16 or S14 connector. Measure the resistance according to the values in the table below. Resistance (Front RH): (C1711/11) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S16-27 (SHFR) - H13-2 (SHFR) Below 1 ohms S16-27 (SHFR) - Body ground 10 kohms or higher Resistance: (Front LH): (C1712/12) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S16-28 (SHFL) - H12-2 (SHFL) Below 1 ohms S16-28 (SHFL) - Body ground 10 kohms or higher Resistance: (Rear RH): (C1713/13) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S14-24 (SHRR) - H26-2 (SHRR) Below 1 ohms S14-24 (SHRR) - Body ground 10 kohms or higher Resistance: (Rear LH): (C1714/14) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S14-23 (SHRL) - H25-2 (SHRL) Below 1 ohms S14-23 (SHRL) - Body ground 10 kohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
8. CHECK HEIGHT CONTROL SENSOR SUB-ASSEMBLY HEIGHT CONTROL SENSOR FRONT RH: (C1711/11) Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 1 (SHB) - 3 (SHG) 4.3 +- 1.3 kohms 1 (SHB) - 2 (SHFR) Repeat about 0.4 to 3.9 kohms Result RESULT SPECIFICATION Result Proceed to OK A NG B HEIGHT CONTROL SENSOR FRONT LH: (C1712/12) Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 1 (SHG) - 3 (SHB) 4.3 +- 1.3 kohms 2 (SHFL) - 3 (SHB) Repeat about 0.4 to 3.9 kohms Result RESULT SPECIFICATION Result Proceed to OK A NG C HEIGHT CONTROL SENSOR REAR RH: (C1713/13) Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 1 (SHG) - 3 (SHB) 4.3 +- 1.3 kohms 2 (SHRR) - 3 (SHB) Repeat about 0.4 to 3.9 kohms Result RESULT SPECIFICATION Result Proceed to OK A NG D HEIGHT CONTROL SENSOR REAR LH: (C1714/14) Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 1 (SHB) - 3 (SHG) 4.3 +- 1.3 kohms 1 (SHB) - 2 (SHRL) Repeat about 0.4 to 3.9 kohms Result RESULT SPECIFICATION Result Proceed to OK A NG E

B: REPLACE HEIGHT CONTROL SENSOR SUBASSEMBLY FRONT RH

C: REPLACE HEIGHT CONTROL SENSOR SUBASSEMBLY FRONT LH

D: REPLACE HEIGHT CONTROL SENSOR SUBASSEMBLY REAR RH

E: REPLACE HEIGHT CONTROL SENSOR SUBASSEMBLY REAR LH

A: REPLACE SUSPENSION CONTROL ECU

The exhaust solenoid is installed in the height control compressor assembly. It discharges high pressure air from the system by opening the solenoid valve according to the signal from the suspension control ECU. The exhaust solenoid continues its operation for max. 60 seconds after the ignition switch is turned off. This takes place in order to discharge the high pressure air which is produced when the vehicle's height is descended by the auto leveling function and access mode or exhausting high pressure air in the pneumatic tank assembly.

HINT

Since high pressure air, which is discharged from the exhaust solenoid is reused for removing moisture by a dryer, discharge speed of the high pressure air is limited. In order to increase the speed of descent of the vehicle's height, some amount of high pressure air is discharged to the pneumatic tank assembly. Then, the stored air in the pneumatic tank assembly is discharged from the exhaust solenoid while the vehicle height control is not in operation.

DIAGNOSTIC TROUBLE CODE CHART

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1. RECONFIRM DTC Check DTCs (See «DTC CHECK / CLEAR»(ref-235991-S34224761592006062900000) ). Confirm if the DTC C1761/61 and/or C1774/74 is recorded. OK: DTC C1761/61 and/or C1774/74 is not output. NG: REPAIR CIRCUIT INDICATED BY OUTPUT CODE OK: Go to next step
2. INSPECT EXHAUST SOLENOID VALVE Disconnect the exhaust solenoid valve connector. Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 1 (SLEX) - 2 (GND) 12 +- 2 ohms Check the operating sound of the exhaust solenoid valve when the battery positive voltage is applied to the terminals. BATTERY SPECIFICATION Battery Positive Battery Negative 1 (SLEX) 2 (GND) OK: It should make an operating sound (click). HINT: When a malfunction is found in the exhaust solenoid valve, replace the height control compressor assembly. NG: REPLACE HEIGHT CONTROL COMPRESSOR ASSEMBLY OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - EXHAUST SOLENOID VALVE) Disconnect the suspension control ECU S14 connector. Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S14-8 (SLEX) - 1 (SLEX) Below 1 ohms S14-8 (SLEX) - Body ground 10 kohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
4. CHECK HARNESS AND CONNECTOR (EXHAUST SOLENOID VALVE - BODY GROUND) Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition (GND) - Body ground Below 1 ohms NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: REPLACE SUSPENSION CONTROL ECU

FRONT HEIGHT CONTROL SOLENOID VALVE

The height control valve sub-assembly No. 1 independently opens and closes paths to the pneumatic cylinder for the front wheel side by receiving the signal from the suspension control ECU. The height control valve sub-assembly No. 1 continues its operation for max. 60 seconds after the ignition switch is turned off. This takes place in order to discharge the high pressure air which is produced when the vehicle's height is lowered by the auto leveling function and in the access mode.

REAR HEIGHT CONTROL SOLENOID VALVE

The height control valve sub-assembly No. 2 independently opens and closes paths to the pneumatic cylinder for the rear wheel side by receiving the signal from suspension control ECU. The height control valve sub-assembly No. 2 continues its operation for max. 60 seconds after the ignition switch is turned off. This takes place in order to discharge the high pressure air which is produced when the vehicle's height is lowered by the auto leveling function and in the access mode.

DIAGNOSTIC TROUBLE CODE CHART

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HINT

Proceed to troubleshooting following the flow chart, regardless of whether or not DTC C1737/31, C1738/ 32, C1739/33 or C1740/34 is displayed.

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1. RECONFIRM DTC Check DTCs (See «DTC CHECK / CLEAR»(ref-235991-S34224761592006062900000) ). Confirm if the DTC C1761/61 and/or C1774/74 is recorded. OK: DTC C1761/61 and/or C1774/74 is output. HINT: If either «DTC C1761/61 (ECU MALFUNCTION)»(ref-235991-S24152757392006062900000) or «C1774/74 (POWER SOURCE CIRCUIT)»(ref-235991-S01907295582006062900000) is displayed, carry out the necessary inspection. If they are output at the same time, carry out the necessary inspection for DTC C1774/74 first. NG: REPAIR CIRCUIT INDICATED BY OUTPUT CODE OK: Go to next step
2. PERFORM ACTIVE TEST BY INTELLIGENT TESTER HINT: When not using intelligent tester, go to step 3. Connect the intelligent tester to the DLC3. Turn the ignition switch to ON position, and push the intelligent tester main switch on. Select the item below in the ACTIVE TEST, and operate it with the intelligent tester. AIRSUS ACTIVE TEST ITEM CHART Item Vehicle Condition / Test Details Diagnostic Note FR SOL Turn OFF right front solenoid valve one second after turning it ON Operation of solenoid (clicking sound) can be heard FL SOL Turn OFF left front solenoid valve one second after turning it ON Operation of solenoid (clicking sound) can be heard RR SOL Turn OFF right rear solenoid valve one second after turning it ON Operation of solenoid (clicking sound) can be heard RL SOL Turn OFF left rear solenoid valve one second after turning it ON Operation of solenoid (clicking sound) can be heard Check whether the height control solenoid valve has continuity (will vibrate). OK: The solenoid makes sound, and the height control solenoid valve has continuity (will vibrate). NG: Go to step 3 OK: REPLACE SUSPENSION CONTROL ECU
3. INSPECT HEIGHT CONTROL SOLENOID VALVE HEIGHT CONTROL SOLENOID VALVE FRONT: Disconnect the height control solenoid valve connector. Measure the resistance according to the values in the table below. Resistance (RH): (C1737/31) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 2 (E) - 3 (RH+) 12 +- 2 ohms Resistance (LH): (C1738/32) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 1 (LH+) 2 - (E) 12 +- 2 ohms Check the operating sound of the height control solenoid valve when positive battery voltage is applied to the terminals. RH: (C1737/31) BATTERY SPECIFICATION Battery Positive Battery Negative 3 (RH+) 2 (E) LH: (C1738/32) BATTERY SPECIFICATION Battery Positive Battery Negative 1 (LH+) 2 (E) OK: It should make an operating sound (click). Result RESULT SPECIFICATION Result Proceed to OK A NG B HINT: When a malfunction is found in the front solenoid valve, replace the height control valve subassembly No. 1. HEIGHT CONTROL SOLENOID VALVE REAR: Disconnect the height control solenoid valve connector. Measure the resistance according to the values in the table below. Resistance (RH): (C1739/33) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 1 (RH+) - 2 (E) 12 +- 2 ohms Resistance (LH): (C1740/34) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 2 (E) - 3 (LH+) 12 +- 2 ohms Resistance: 12 +- 2 ohms Check the operating sound of the height control solenoid valve when positive battery voltage is applied to the terminals. RH: (C1739/39) BATTERY SPECIFICATION Battery Positive Battery Negative 1 (RH+) 2 (E) LH: (C1740/34) BATTERY SPECIFICATION Battery Positive Battery Negative 3 (LH+) 2 (E) OK: It should make an operating sound (click). Result RESULT SPECIFICATION Result Proceed to OK A NG C HINT: When a malfunction is found in the front solenoid valve, replace the height control valve subassembly No. 2. B: REPLACE HEIGHT CONTROL VALVE SUBASSEMBLY NO. 1 C: REPLACE HEIGHT CONTROL VALVE SUBASSEMBLY NO. 2 A: Go to next step
4. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - HEIGHT CONTROL SOLENOID VALVE) Disconnect the suspension control ECU S14 connector. Measure the resistance according to the values in the table below. Resistance (Front RH): (C1737/31) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S14-9 (SLFR) - H14-3 (RH+) Below 1 ohms S14-9 (SLFR) - Body ground 10 kohms or higher Resistance (Front LH): (C1738/32) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S14-10 (SLFL) - H14-1 (LH+) Below 1 ohms S14-10 (SLFL) - Body ground 10 kohms or higher Resistance (Rear RH): (C1739/33) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S14-2 (SLRR) - H27-1 (RH+) Below 1 ohms S14-2 (SLRR) - Body ground 10 kohms or higher Resistance (Rear LH): (C1740/34) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S14-1 (SLRL) - H27-3 (LH+) Below 1 ohms S14-1 (SLRL) - Body ground 10 kohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. CHECK HARNESS AND CONNECTOR (HEIGHT CONTROL SOLENOID VALVE - BODY GROUND) Measure the resistance according to the values in the table below. Resistance (Front RH): (C1737/31) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition H14-3 (RH+) - Body ground Below 1 ohms Resistance (Front LH): (C1738/32) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition H14-1 (LH+) - Body ground Below 1 ohms Resistance (Rear RH): (C1739/33) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition H27-1 (RH+) - Body ground Below 1 ohms Resistance (Rear LH): (C1740/34) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition H27-3 (LH+) - Body ground Below 1 ohms

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE SUSPENSION CONTROL ECU

The signal from the suspension control ECU switches ON the AIR SUS relay, and then the height control compressor motor starts.

DTC CHART

Scheme 39

Scheme 40

Scheme 41

Scheme 42

1. RECONFIRM DTC Check DTCs (See «DTC CHECK / CLEAR»(ref-235991-S34224761592006062900000) ). Confirm if the DTC C1761/61 and/or C1774/74 is recorded. OK: DTC C1761/61 and/or C1774/74 is not output. HINT: If either «DTC C1761/61 (ECU MALFUNCTION)»(ref-235991-S24152757392006062900000) or «C1774/74 (POWER SOURCE CIRCUIT)»(ref-235991-S01907295582006062900000) is displayed, carry out the necessary inspection. If they are output at the same time, carry out the necessary inspection for DTC C1774/74 first. NG: REPAIR CIRCUIT INDICATED BY OUTPUT CODE OK: Go to next step
2. PERFORM ACTIVE TEST BY INTELLIGENT TESTER HINT: When not using intelligent tester, go to step 3. Connect the intelligent tester to the DLC3. Turn the ignition switch to the ON position, and push the intelligent tester main switch ON. Select the item below in the ACTIVE TEST, and operate it with the intelligent tester. AIRSUS ACTIVE TEST ITEM CHART Item Vehicle Condition / Test Details Diagnostic Note MOTOR RELAY AIR SUS relay / ON or OFF - Check the operation sound of the AIR SUS relay when operating it with the intelligent tester. OK: The operation sound of the AIR SUS relay can be head. NG: Go to step 3 OK: REPLACE SUSPENSION CONTROL ECU
3. INSPECT AIR SUS RELAY Remove the AIR SUS relay from the engine room R/B. Remove the AIR SUS relay from the engine room R/B. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 3 - 5 10 kohms higher Below 1 ohms (When battery voltage is applied to terminals 1 and 2) NG: REPLACE AIR SUS RELAY OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - AIR SUS RELAY) Disconnect the suspension control ECU S14 connector. Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S14-18 (RC) - 1 (for AIR SUS relay) Below 1 ohms S14-18 (RC) - Body ground 10 kohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. CHECK HARNESS AND CONNECTOR (AIR SUS RELAY - BODY GROUND) Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 2 (for AIR SUS relay) - Body ground Below 1 ohms

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE SUSPENSION CONTROL ECU

The signal from suspension control ECU turns on the AIR SUS relay. At the time, battery voltage is input to height control compressor motor through the AIR SUS relay. The height control compressor motor starts.

DTC CHART

Scheme 43

Refer to DTC C1735/35, C1737/31, C1744/44.

Scheme 44

Scheme 45

Scheme 46

Scheme 47

Scheme 48

Scheme 49

Scheme 50

Scheme 51

Scheme 52

Scheme 53

Scheme 54

1. RECONFIRM DTC Check if DTC C1741/41 is output (See «DTC C1741/41 AIR SUSPENSION RELAY CIRCUIT»(ref-235991-S21044994902006062900000) ). OK: DTC C1741/41 is output. DIAGNOSTIC TROUBLE CODE CHART DTC C1741/41 is output. A Other DTC is output B NG: REPAIR CIRCUIT INDICATED BY OUTPUT CODE OK: Go to next step
2. INSPECT HEIGHT CONTROL COMPRESSOR Disconnect the height control compressor motor connector. Check the operating sound of the compressor motor when battery positive voltage is applied to the terminals. BATTERY SPECIFICATION Battery Positive Battery Negative 1 (B) 2 (L) OK: Compressor motor operates. NOTE: Do not operate the height control compressor assembly 60 seconds. or more. Since a short and a lock-up inside the height control compressor assembly causes enormous current to flow, stop operation immediately when it does not rotate. HINT: When a malfunction is found in the height control compressor motor, replace the height control compressor assembly. NG: REPLACE CONTROL COMPRESSOR ASSEMBLY OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - HEIGHT CONTROL COMPRESSOR MOTOR) Connect the height control compressor motor connector. Disconnect the suspension control ECU S14 connector. Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S14-25 (RM+) - S14-26 (RM-) 6.4 to 7.4 ohms NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (HEIGHT CONTROL COMPRESSOR MOTOR - BODY GROUND) Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 2 (L) - Body ground Below 1 ohms NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. CHECK HARNESS AND CONNECTOR (HEIGHT CONTROL COMPRESSOR MOTOR - AIR SUS RELAY) Disconnect the AIR SUS relay from the engine room R/ B. Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 1 (B) - 3 (for AIR SUS relay) Below 1 ohms 1 (B) - Body ground 10 kohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
6. CHECK HARNESS AND CONNECTOR (AIR SUS RELAY - AIR SUS FUSE) Measure the voltage according to the values in the table below. Voltage TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 5 (for AIR SUS relay) - Body ground 11 to 14 V Result RESULT SPECIFICATION Result Proceed to OK A (When using intelligent tester) (Referece) B (When not using intelligent tester) NG C B: Go to step 8 C: REPAIR OR REPLACE HARNESS OR CONNECTOR A: Go to next step
7. INSPECT HEIGHT CONTROL SOLENOID VALVE Connect the intelligent tester to the DLC3. Turn the ignition switch to the ON position, and push the intelligent tester main switch on. Select the item below in the ACTIVE TEST, and operate it with the intelligent tester. AIRSUS ACTIVE TEST ITEM CHART Item Vehicle Condition / Test Details Diagnostic Note FR SOL Turn OFF right front solenoid valve one second after turning it ON Operation of solenoid (clicking sound) can be heard FL SOL Turn OFF left front solenoid valve one second after turning it ON Operation of solenoid (clicking sound) can be heard RR SOL Turn OFF right rear solenoid valve one second after turning it ON Operation of solenoid (clicking sound) can be heard RL SOL Turn OFF left rear solenoid valve one second after turning it ON Operation of solenoid (clicking sound) can be heard Check whether the height control solenoid valve has a continuity (will vibrate). OK: The solenoid makes sound, and the height control solenoid valve has continuity (will vibrate). OK: Go to step 9 NG: Go to next step
8. INSPECT HEIGHT CONTROL SOLENOID VALVE HEIGHT CONTROL SOLENOID VALVE FRONT RH: Disconnect the height control solenoid valve connector. Check the operating sound of the height control solenoid valve when positive battery voltage is applied to the terminals. BATTERY SPECIFICATION Tester Connection Battery Positive Battery Negative 3 (RH+) 2 (E) OK: It should make an operating sound (click). Result RESULT SPECIFICATION Result Proceed to OK A NG B HINT: When a malfunction is found in the front solenoid valve, replace the height control valve subassembly No. 1. HEIGHT CONTROL SOLENOID VALVE FRONT LH: Disconnect the height control solenoid valve connector. Check the operating sound of the height control solenoid valve when positive battery voltage is applied to the terminals. BATTERY SPECIFICATION Battery Positive Battery Negative 1 (LH+) 2 (E) OK: It should make an operating sound (click). Result RESULT SPECIFICATION Result Proceed to OK A NG B HINT: When a malfunction is found in the front solenoid valve, replace the height control valve subassembly No. 1. HEIGHT CONTROL SOLENOID VALVE REAR RH: Disconnect the height control solenoid valve connector. Check the operating sound of the height control solenoid valve when positive battery voltage is applied to the terminals. BATTERY SPECIFICATION Battery Positive Battery Negative 1 (RH+) 2 (E) OK: It should make an operating sound (click). Result RESULT SPECIFICATION Result Proceed to OK A NG C HINT: When a malfunction is found in the rear solenoid valve, replace the height control valve subassembly No. 2. HEIGHT CONTROL SOLENOID VALVE REAR LH: Disconnect the height control solenoid valve connector. Check the operating sound of the height control solenoid valve when positive battery voltage is applied to the terminals. BATTERY SPECIFICATION Battery Positive Battery Negative 3 (LH+) 2 (E) OK: It should make an operating sound (click). Result RESULT SPECIFICATION Result Proceed to OK A NG C HINT: When a malfunction is found in the rear solenoid valve, replace the height control valve subassembly No. 2. B: REPLACE HEIGHT CONTROL VALVE SUBASSEMBLY NO. 1 C: REPLACE HEIGHT CONTROL VALVE SUBASSEMBLY NO. 2 A: Go to next step
9. INSPECT EXHAUST SOLENOID VALVE Disconnect the exhaust solenoid valve connector. Check the operating sound of the exhaust solenoid valve when positive battery voltage is applied to the terminals. BATTERY SPECIFICATION Battery Positive Battery Negative 1 (SLEX) 2 (GND) OK: It should make an operating sound (click). HINT: When a malfunction is found in the exhaust solenoid valve, replace the height control compressor assembly. Result RESULT SPECIFICATION Result Proceed to OK A (When using intelligent tester) (Referece) B (When not using intelligent tester) NG C B: Go to step 11 C: REPLACE HEIGHT CONTROL COMPRESSOR ASSEMBLY A: Go to next step
10. INSPECT TANK SOLENOID VALVE Connect the intelligent tester to the DLC3. Turn the ignition switch to the ON position, and push the intelligent tester main switch on. Select the item below in the ACTIVE TEST, and operate it with the intelligent tester. AIRSUS ACTIVE TEST ITEM CHART Item Vehicle Condition / Test Details Diagnostic Note LOW PRS TNK SOL Turn tank solenoid valve / ON or OFF Operation of solenoid (clicking sound) can be heard Check whether the tank solenoid valve has a continuity (will vibrate). OK: The solenoid makes sound, and the tank solenoid valve has a continuity (will vibrate). OK: Go to step 12 NG: REPLACE PNEUMATIC W/TUBE TANK ASSEMBLY
11. INSPECT TANK SOLENOID VALVE Disconnect the exhaust solenoid valve connector. Check the operating sound of the tank solenoid valve when positive battery voltage is applied to the terminals. BATTERY SPECIFICATION Battery Positive Battery Negative 1 (SLLO) 2 (GND) OK: The solenoid makes sound, and the tank solenoid valve has a continuity (will vibrate). HINT: When a malfunction is found in the tank solenoid valve, replace the pneumatic tank assembly. NG: REPLACE PNEUMATIC W/TUBE TANK ASSEMBLY OK: Go to next step
12. INSPECT FOR CLOGGED AIR TUBE Check visually for a clog, damage or breakage on the air tube (See «ON-VEHICLE INSPECTION»(ref-235991-S37843268602006062900000) ). NG: REPAIR OR REPLACE AIR TUBE OK: REPLACE SUSPENSION CONTROL ECU

The tank solenoid which is installed in the pneumatic tank assembly operates the solenoid valve according to the signal from suspension control ECU. When lowering the vehicle height, high pressure air in the system is discharged to the pneumatic tank assembly. When the vehicle height control is suspended, the high pressure air in the pneumatic tank assembly is discharged. The tank solenoid continues its operation for max. 60 seconds after the ignition switch is turned off. This takes place in order to discharge the high pressure air which is produced when the vehicle height is lowered by the auto leveling function and access mode or exhausting high pressure air in the pneumatic tank assembly.

HINT

Since high pressure air which is discharged from the exhaust solenoid is reused for removing moisture in the dryer, discharge speed of the high pressure air is limited. In order to increase the speed of lowering the vehicle height, some amount of high pressure air is discharged to the pneumatic tank assembly. Then, the stored air in the pneumatic tank assembly is discharged from the exhaust solenoid while the vehicle height control is not in operation.

DTC CHART

Scheme 55

Scheme 56

Scheme 57

Scheme 58

1. CHECK DTC OUTPUT Check DTCs (See «DTC CHECK / CLEAR»(ref-235991-S34224761592006062900000) ). Confirm if the DTC C1761/61 and/or C1774/74 is recorded. OK: DTC C1761/61 and/or C1774/74 is not output. HINT: If either «DTC C1761/61 (ECU MALFUNCTION)»(ref-235991-S24152757392006062900000) or «C1774/74 (POWER SOURCE CIRCUIT)»(ref-235991-S01907295582006062900000) is displayed, carry out the necessary inspection. If they are output at the same time, carry out the necessary inspection for DTC C1774/74 first. NG: REPAIR CIRCUIT INDICATED BY OUTPUT CODE OK: Go to next step
2. PERFORM ACTIVE TEST BY INTELLIGENT TESTER HINT: When not using intelligent tester, go to step 3. Connect the intelligent tester to the DLC3. Turn the ignition switch to the ON position, and push the intelligent tester main switch on. Select the item below in the ACTIVE TEST, and operate it with the intelligent tester. AIRSUS ACTIVE TEST ITEM CHART Item Vehicle Condition / Test Details Diagnostic Note LOW PRS TNK SOL Turn OFF tank solenoid valve one second after turning it ON Operation of solenoid (clicking sound) can be heard Check whether the tank solenoid valve has a continuity (will vibrate). OK: The solenoid makes sound, and the tank solenoid valve has a continuity (will vibrate). NG: Go to step 3 OK: REPLACE SUSPENSION CONTROL ECU
3. INSPECT TANK SOLENOID VALVE Disconnect the tank solenoid valve connector. Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition 1 (SLLO) - 2 (GND) 12 +- 2 ohms Check the operating sound of the tank solenoid valve when positive battery voltage is applied to the terminals. BATTERY SPECIFICATION Battery Positive Battery Negative 1 (SLLO) 2 (GND) OK: It should make an operating sound (click). HINT: When a malfunction is found in the tank solenoid valve, replace the pneumatic tank assembly. NG REPLACE PNEUMATIC W/TUBE TANK ASSEMBLY OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - TANK SOLENOID VALVE) Disconnect the suspension control ECU S14 connector. Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S14-7 (SLLO) - P7-1 (SLLO) Below 1 ohms S14-7 (SLLO) - Body ground 10 kohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. CHECK HARNESS AND CONNECTOR (TANK SOLENOID VALVE - BODY GROUND) Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition P7-2 (GND) - Body ground Below 1 ohms

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE SUSPENSION CONTROL ECU

The signal from the suspension control ECU operates the air suspension relay, and the height control compressor motor starts. The height control compressor assembly operates until the targeted vehicle height is reached. Then the height control sensor sub-assembly sends the signal to the suspension control ECU, and stops the height control compressor.

DTC CHART

Scheme 59

Scheme 60

Scheme 61

Scheme 62

Scheme 63

Scheme 64

1. CHECK VEHICLE HEIGHT HINT: Make the vehicle vacant and unloaded.
2. CHECK HEIGHT CONTROL COMPRESSOR CIRCUIT
3. CHECK AIR LEAKAGE OK: No leaks Result RESULT SPECIFICATION Result Proceed to OK A (When using intelligent tester) (Reference) B (When not using intelligent tester) NG C B: Go to step 5 C: REPAIR OR REPLACE AIR TUBE A: Go to next step
4. INSPECT HEIGHT CONTROL SOLENOID VALVE Connect the intelligent tester to the DLC3. Turn the ignition switch to the ON position, and push the intelligent tester main switch on. Select the item below in the ACTIVE TEST, and operate it with the intelligent tester. AIRSUS ACTIVE TEST ITEM CHART Item Vehicle Condition / Test Details Diagnostic Note FR SOL Turn OFF right front solenoid valve one second after turning it ON Operation of solenoid (clicking sound) can be heard FR SOL Turn OFF left front solenoid valve one second after turning it ON Operation of solenoid (clicking sound) can be heard RR SOL Turn OFF right rear solenoid valve one second after turning it ON Operation of solenoid (clicking sound) can be heard RL SOL Turn OFF left rear solenoid valve one second after turning it ON Operation of solenoid (clicking sound) can be heard Check whether the height control solenoid valve has a continuity (will vibrate). OK: The solenoid makes sound, and the height control solenoid valve has continuity (will vibrate). OK: Go to step 6 NG: Go to next step
5. INSPECT HEIGHT CONTROL SOLENOID VALVE HEIGHT CONTROL SOLENOID VALVE FRONT RH: Disconnect the height control solenoid valve connector. Check the operating sound of the height control solenoid valve when positive battery voltage is applied to the terminals. BATTERY SPECIFICATION Battery Positive Battery Negative 3 (RH+) 2 (E) OK: It should make an operating sound (click). Result RESULT SPECIFICATION OK A NG B HINT: When a malfunction is found in the front solenoid valve, replace the height control valve sub-assembly No. 1. HEIGHT CONTROL SOLENOID VALVE FRONT LH: Disconnect the height control solenoid valve connector. Check the operating sound of the height control solenoid valve when positive battery voltage is applied to the terminals. BATTERY SPECIFICATION Battery Positive Battery Negative 1 (LH+) 2 (E) OK: It should make an operating sound (click). Result RESULT SPECIFICATION OK A NG B HINT: When a malfunction is found in the front solenoid valve, replace the height control valve subassembly No. 1. HEIGHT CONTROL SOLENOID VALVE REAR RH: Disconnect the height control solenoid valve connector. Check the operating sound of the height control solenoid valve when positive battery voltage is applied to the terminals. BATTERY SPECIFICATION Battery Positive Battery Negative 1 (RH+) 2 (E) OK: It should make an operating sound (click). Result RESULT SPECIFICATION OK A NG C HINT: When a malfunction is found in the front solenoid valve, replace the height control valve subassembly No. 2. HEIGHT CONTROL SOLENOID VALVE REAR LH: Disconnect the height control solenoid valve connector. Check the operating sound of the height control solenoid valve when positive battery voltage is applied to the terminals. BATTERY SPECIFICATION Battery Positive Battery Negative 3 (LH+) 2 (E) OK: It should make an operating sound (click). Result RESULT SPECIFICATION OK A NG C HINT: When a malfunction is found in the front solenoid valve, replace the height control valve subassembly No. 2. B: REPLACE HEIGHT CONTROL VALVE SUBASSEMBLY NO. 1 C: REPLACE HEIGHT CONTROL VALVE SUBASSEMBLY NO. 2 A: Go to next step
6. INSPECT EXHAUST SOLENOID VALVE Disconnect the exhaust solenoid valve connector. Check the operating sound of the exhaust solenoid valve when positive battery voltage is applied to the terminals. BATTERY SPECIFICATION Battery Positive Battery Negative 1 (SLEX) 2 (GND) OK: It should make an operating sound (click). Result RESULT SPECIFICATION Result Proceed to OK A (When using intelligent tester) (Reference) B (When not using intelligent tester) NG C B: Go to step 8 C: REPLACE EIGHT CONTROL COMPRESSOR ASSEMBLY A: Go to next step
7. INSPECT TANK SOLENOID VALVE Connect the intelligent tester to the DLC3. Turn the ignition switch to the ON position, and push the intelligent tester main switch on. Select the item below in the ACTIVE TEST, and operate it with the intelligent tester. AIRSUS ACTIVE TEST ITEM CHART Item Vehicle Condition / Test Details Diagnostic Note LOW PRS TNK SOL Turn OFF tank solenoid valve one second after turning it ON Operation of solenoid (clicking sound) can be heard Check whether the tank solenoid valve has a continuity (will vibrate). OK: The solenoid makes sound, and the tank solenoid valve has a continuity (will vibrate). OK: Go to step 9 NG: REPLACE PNEUMATIC W/TUBE TANK ASSEMBLY
8. INSPECT TANK SOLENOID VALVE Disconnect the tank solenoid valve connector. Check the operating sound of the tank solenoid valve when positive battery voltage is applied to the terminals. BATTERY SPECIFICATION Battery Positive Battery Negative 1 (SLEX) 2 (GND) OK: It should make an operating sound (click). HINT: When a malfunction is found in the tank solenoid valve, replace the pneumatic tank assembly. NG: REPLACE PNEUMATIC W/TUBE TANK ASSEMBLY OK: Go to next step
9. INSPECT HEIGHT CONTROL SENSOR LINK SUB-ASSEMBLY Inspect and adjust the height control sensor link subassembly (See «REMOVAL»(ref-235991-S23938144912006062900000) ).
10. SYSTEM CHECK Change the height control switch to the "N" position. Change the height control switch to the "H" position. Check that the vehicle height changes from the "N" to the "H" position. HINT: When the vehicle height does not change, proceed to the next step. NEXT: CHECK AIR SUSPENSION SYSTEM

DTC CHART

Scheme 65

1. CONFIRM DTC Check DTCs (See «DTC CHECK / CLEAR»(ref-235991-S34224761592006062900000) ). Confirm if the DTC C1774/74 is recorded. OK: DTC C1774/74 is not output. HINT: If DTC C1774/74 (power source circuit) is displayed, carry out the inspection necessary. (See «DTC C1774/74 POWER SOURCE CIRCUIT»(ref-235991-S01907295582006062900000) ). If DTC C1711/11 (right front height control sensor circuit), C1712/12 (left front height control sensor circuit), C1713/13 (right rear height control sensor circuit), C1714/14 (left rear height control sensor circuit) and C1761/61 (ECU malfunction) is output at the same time, carry out the inspection necessary for DTC C1761/61 first. NG: REPAIR CIRCUIT INDICATED BY OUTPUT CODE OK: Go to next step
2. CHECK HEIGHT CONTROL OFF INDICATOR LIGHT Turn the ignition switch to the ON position. Check the height control OFF indicator light. OK: Height control OFF indicator light comes on. NG: REPLACE SUSPENSION CONTROL ECU OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (HEIGHT CONTROL SENSOR SUB-ASSEMBLY POWER SOURCE)) Disconnect the height control sensor sub-assembly connector. Turn the ignition switch ON. Measure the voltage according to the values in the table below. Resistance (Front RH): TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition H13-1 (SHB) - H13-3 (SHG) 4.75 to 5.25 V Resistance: (Front LH): TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition H12-1 (SHG) - H12-3 (SHB) 4.75 to 5.25 V Resistance: (Rear RH): TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition H26-1 (SHG) - H26-?3 (SHB) 4.75 to 5.25 V Resistance: (Rear LH): TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition H25-1 (SHB) - H25-3 (SHG) 4.75 to 5.25 V NG: CHECK HEIGHT CONTROL SENSOR SUBASSEMBLY CIRCUIT OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - AFS ECU) Turn the ignition switch to the OFF position. Disconnect the suspension control ECU S15 connector. Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S15-19 (SBL3) - Body ground 10 kohms or higher NG: REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. INSPECT SUSPENSION CONTROL ECU Turn the ignition switch to the OFF position. Measure the voltage according to the values in the table below. Voltage TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S15-6 (B) - S16-1 (GND) 10 to 14 V S15-6 (B) - S15-5 (GND2) 10 to 14 V NG: CHECK POWER SOURCE CIRCUIT OK: REPLACE SUSPENSION CONTROL ECU

Battery voltage is constantly applied to the +B terminal of the suspension control ECU. It is applied to the IG terminal when the ignition switch is on.

DTC CHART

Scheme 66

Scheme 67

Scheme 68

Scheme 69

1. CHECK SOURCE VOLTAGE Check the positive battery voltage. Voltage: 10 to 14 V NG: REPLACE BATTERY OK: Go to next step
2. INSPECT FUSE (AIR SUS NO. 2) Remove the AIR SUS No. 2 fuse and ECU-IG fuse from the instrument panel J/B. Check fuse. Check continuity of the AIR SUS No. 2 fuse. Standard: Continuity NG: REPLACE FUSE OK: Go to next step
3. INSPECT FUSE (ECU-IG) Remove the ECU-IG fuse from the instrument panel J/B. Check fuse. Check continuity of the ECU-IG fuse. Standard: Continuity Result RESULT SPECIFICATION Result Proceed to OK A (When using intelligent tester) (Reference) B (When not using intelligent tester) NG C B: Go to step 5 C: REPLACE FUSE A: Go to next step
4. INSPECT SUSPENSION CONTROL ECU Connect the intelligent tester to the DLC3. Turn the ignition switch to the ON position, and push the intelligent tester main switch on. Select the item below in the ACTIVE TEST, and operate it with the intelligent tester. AIRSUS ITEM CHART Item Normal condition IG VOLTAGE Actual ECU power supply voltage: 10 to 14 V POWER VOLTAGE Actual ECU power supply voltage: 10 to 14 V Check the voltage. Voltage: 10 to 14 V NG: Go to step 6 OK: REPLACE SUSPENSION CONTROL ECU
5. INSPECT SUSPENSION CONTROL ECU Remove the suspension control ECU with connectors being connected. Turn the ignition switch to the ON position. Measure the voltage according to the values in the table below. Voltage TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S15-6 (B) - S16-1 (GND) 10 to 14 V S15-6 (B) - S15-5 (GND2) 10 to 14 V S16-10 (IG) - S16-1 (GND) 10 to 14 V S16-10 (IG) - S15-5 (GND2) 10 to 14 V NG: Go to step 6 OK: REPLACE SUSPENSION CONTROL ECU
6. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - BODY GROUND) Disconnect the suspension control ECU S15 and S16 connectors. Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S16-1 (GND) - Body ground Below 1 ohms S15-5 (GND2) - Body ground Below 1 ohms Result RESULT SPECIFICATION Result Proceed to NG Repair or replace the harness or the connector between the suspension control ECU and body ground. OK When B terminal malfunctions: Repair or replace the harness or the connector between the AIR SUS No. 2 fuse and the suspension control ECU. When IG terminal malfunctions: Repair or replace the harness or the connector between the ECU-IG fuse and the suspension control ECU. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: REPLACE SUSPENSION CONTROL ECU

The speed sensor monitors the speed of a wheel, and sends an appropriate speed signal to the suspension control ECU through the brake actuator assembly (skid control ECU). If trouble occurs in the either right rear speed sensor or left rear speed sensor, the DTC (C1776/76) is output. When inspecting by test mode, the suspension control ECU scans changes of the signals. If there is no change, it outputs the test DTC (C1784/84, C1785/85).

DTC CHART

HINT

When DTC C1784/84 and C1785/85 are output, follow the same procedure as DTC 1776/76.

Scheme 70

The suspension control ECU receives the engine speed signal from the ECM. When inspecting by test mode, the suspension control ECU scans changes in the signals. If there is no change, it outputs the test DTC (C1797/97).

DTC CHART

HINT

When DTC C1797/97 is output, follow the same procedure as that of DTC1779/79.

Scheme 71

When the brake pedal is depressed, the stop lights come on and the signal is sent to the STP terminal of suspension control ECU. When inspecting by test mode, the suspension control ECU scans changes to the signals. If there is no change, it outputs the test DTC (C1782/82).

DTC CHART

Scheme 72

Scheme 73

Scheme 74

Scheme 75

1. CHECK STOP LIGHT SWITCH OPERATION Check that the stop light comes on when the brake pedal is depressed and goes off when the brake pedal is released. OK: Stop light switch functions normally. NG: Go to step 3 OK: Go to next step
2. INSPECT SUSPENSION CONTROL ECU Disconnect the suspension control ECU S15 connector. Measure the voltage according to the values in the table below. Voltage TESTER CONNECTION SPECIFIED CONDITION Switch Condition Tester Connection Specified Condition Brake pedal depressed S15-12 (STP) - Body ground 10 to 14 V Brake pedal released S15-12 (STP) - Body ground Below 1.5 V NG: Go to step **** OK: REPLACE SUSPENSION CONTROL ECU
3. INSPECT STOP LIGHT SWITCH ASSEMBLY Disconnect the stop light switch assembly connector. Measure the voltage according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Switch Condition Tester Connection Specified Condition Switch pin free 1 - 2 Below 1 ohms Switch pin pushed in 1 - 2 10 kohms or higher NG: REPLACE STOP LIGHT SWITCH ASSEMBLY OK: Go to next step
4. INSPECT SUSPENSION CONTROL ECU Disconnect the suspension control ECU S15 connector. Measure the voltage according to the values in the table below. Voltage TESTER CONNECTION SPECIFIED CONDITION Switch Condition Tester Connection Specified Condition Brake pedal depressed S15-12 (STP) - Body ground 10 to 14 V Brake pedal released S15-12 (STP) - Body ground Below 1.5 V

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE SUSPENSION CONTROL ECU

By controlling the height control switch, the vehicle height can be set 30 mm (1.18 in.) higher in "HI mode" and 15 mm (0.59 in.) lower in "LO mode" than normal vehicle height. Even though the vehicle is operated in normal mode, the vehicle height is set approx. 7.5 mm (0.295 in.) lower than normal vehicle height while driving at high speed.

HINT

Driving in the "HI mode" is only possible when the vehicle's speed is less than 30 km/h (19 mph).

DTC CHART

Scheme 76

When selecting the height control OFF switch, all the vehicle height controls are suspended. Do not work under the vehicle, when the height control OFF switch does not operate properly. Disallowance of the vehicle height control is recorded even when the minus terminal of the battery is disconnected.

DTC CHART

Scheme 77

By selecting the access mode switch, the vehicle's height is set approx. 25 mm (0.98 in.) (approx. 30 mm (1.18 in.) for 4WD) lower than normal vehicle height. While driving, vehicle height returns to the previously selected position.

HINT

If the vehicle height mode is set in "HI mode", the access mode can not be operated.

DTC CHART

Scheme 78

The height control indicator light indicates the target height, not the actual height. It blinks when the height control is operated by pressing the height control switch and stays on when the operation is completed. 05CI9?01

Scheme 79

Scheme 80

Scheme 81

1. INSPECT COMBINATION METER ASSEMBLY (HEIGHT CONTROL INDICATOR LIGHT) Remove the combination meter assembly. Check indicator light on the combination meter assembly. Check that the height control indicator light (HI, N, LO) comes on of the combination meter assembly when positive battery voltage is applied to the terminals as shown in the chart below. BATTERY SPECIFICATION Indicator Light Battery Positive Battery Negative HI C8-16 C8-12 N C8-16 C8-11 LO C8-16 C8-10 OK: Height control indicator light (HI, N, LO) comes on. NG: REPLACE COMBINATION METER ASSEMBLY OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - COMBINATION METER ASSEMBLY) Disconnect the suspension control ECU S16 connector. Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S16-16 (HI) - C8-12 Below 1 ohms S16-17 (NR) - C8-11 Below 1 ohms S16-18 (LO) - C8-10 Below 1 ohms S16-16 (HI) - Body ground 10 kohms or higher S16-17 (NR) - Body ground 10 kohms or higher S16-18 (LO) - Body ground 10 kohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: REPLACE PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

If the suspension control ECU detects a problem, the height control OFF indicator light comes on while suspending the height control function at the same time. At this time, the suspension control ECU records a DTC. Connect terminal TC and CG of the DLC3 to make the height control OFF indicator light flash and output DTC.

Scheme 82

Scheme 83

Scheme 84

1. INSPECT COMBINATION METER ASSEMBLY (HEIGHT CONTROL OFF INDICATOR LIGHT) Remove the combination meter. Check indicator light on the combination meter assembly. Check that the height control OFF indicator light comes on when battery positive voltage is applied to the terminals as shown in the chart below. BATTERY SPECIFICATION Indicator Light Battery Positive Battery Negative OFF C8-16 C8-9 OK: Height control OFF indicator light comes on. NG: REPLACE COMBINATION METER ASSEMBLY OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - COMBINATION METER ASSEMBLY) Disconnect the suspension control ECU S16 connector. Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S16-15 (OFID) - C8-9 Below 1 ohms S16-15 (OFID) - Body ground 10 kohms or higher

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

DTC is output when there is a short circuit between terminal TC and CG of the DLC3.

Scheme 85

Scheme 86

Scheme 87

Scheme 88

Scheme 89

1. INSPECT DLC3 TERMINAL VOLTAGE (TC TERMINAL) Turn the ignition switch to the ON position. Measure the voltage according to the value in the table below. Voltage TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition D1-13 (TC) - D1-4 (CG) 10 to 14 V NG: Go to step 3 OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - DLC3) Disconnect the suspension control ECU S16 connector. Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S16-6 (TC) - D1-13 (TC) Below 1 ohms S16-6 (TC) - Body ground 10 kohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: REPLACE SUSPENSION CONTROL ECU
3. CHECK HARNESS AND CONNECTOR (DLC3 - BODY GROUND) Measure the resistance according to the value in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition D1-4 (CG) - Body ground Below 1 ohms Disconnect the suspension control ECU S16 connector. Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S16-6 (TC) - D1-13 (TC) Below 1 ohms S16-6 (TC) - Body ground 10 kohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - DLC3) NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: REPLACE SUSPENSION CONTROL ECU

Connect terminals TS and CG of the DLC3 with the ignition switch OFF. When the ignition switch is turned to the ON position, test mode will started and then the DTCs will be output.

Scheme 90

Scheme 91

Scheme 92

Scheme 93

Scheme 94

1. INSPECT DLC3 TERMINAL VOLTAGE (TS TERMINAL) Turn the ignition switch to the ON position. Measure the voltage according to the value in the table below. Voltage TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition D1-12 (TS) - D1-4 (CG) 10 to 14 V NG: Go to step 3 OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - DLC3) Disconnect the suspension control ECU S16 connector. Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S16-5 (TS) - D1-12 (TS) Below 1 ohms S16-5 (TS) - Body ground 10 kohms or higher NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: REPLACE SUSPENSION CONTROL ECU
3. CHECK HARNESS AND CONNECTOR (DLC3 - BODY GROUND) Measure the resistance according to the value in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition D1-4 (CG) - Body ground Below 1 ohms NG: REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - DLC3) Disconnect the suspension control ECU S16 connector. Measure the resistance according to the values in the table below. Resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition S16-5 (TS) - D1-12 (TS) Below 1 ohms S16-5 (TS) - Body ground 10 kohms or higher

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE SUSPENSION CONTROL ECU

Scheme 95

See also:
• ON-VEHICLE INSPECTION