C1738
SUSPENSION CONTROL: AIR SUSPENSION SYSTEM: C1737/31: Right Front Height Control Solenoid Valve Circuit
DTC C1737/31 - Right Front Height Control Solenoid Valve Circuit
DTC C1738/32 - Left Front Height Control Solenoid Valve Circuit
DTC C1739/33 - Right Rear Height Control Solenoid Valve Circuit
DTC C1740/34 - Left Rear Height Control Solenoid Valve Circuit
DESCRIPTION
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.
WIRING DIAGRAM
INSPECTION PROCEDURE
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.
PROCEDURE
1. RECONFIRM DTC
(a) Check DTCs .
(1) 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 DTCC1761/61 (ECU malfunction) C1761 or C1774/74 (power source circuit) C1774 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 -- Continue to next step.
2. PERFORM ACTIVE TEST USING INTELLIGENT TESTER
HINT: When not using intelligent tester, go to step 3.
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch to ON position, and push the intelligent tester main switch on.
(c) Select the item below in the ACTIVE TEST, and operate it with the intelligent tester.
AIRSUS:
(d) 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 -- INSPECT HEIGHT CONTROL SOLENOID VALVE
OK -- REPLACE SUSPENSION CONTROL ECU
3. INSPECT HEIGHT CONTROL SOLENOID VALVE
(a) HEIGHT CONTROL SOLENOID VALVE FRONT:
(1) Disconnect the height control solenoid valve connector.
(2) Measure the resistance according to the values in the table below.
Standard resistance (RH): (C1737/31):
Standard resistance (LH): (C1738/32):
(3) Check the operating sound of the height control solenoid valve when positive battery voltage is applied to the terminals.
OK:
It should make an operating sound (click).
Result:
HINT: When a malfunction is found in the front solenoid valve, replace the height control valve sub-assembly No. 1.
(b) HEIGHT CONTROL SOLENOID VALVE REAR:
(1) Disconnect the height control solenoid valve connector.
(2) Measure the resistance according to the values in the table below.
Standard resistance (RH): (C1739/33):
Standard resistance (LH): (C1740/34):
Standard resistance:
12 ± 2 Ohms
(3) Check the operating sound of the height control solenoid valve when positive battery voltage is applied to the terminals.
OK:
It should make an operating sound (click).
Result:
HINT: When a malfunction is found in the front solenoid valve, replace the height control valve sub-assembly No. 2.
C -- REPLACE HEIGHT CONTROL VALVE SUB-ASSEMBLY NO.2
B -- REPLACE HEIGHT CONTROL VALVE SUB-ASSEMBLY NO.1
A -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - HEIGHT CONTROL SOLENOID VALVE)
(a) Disconnect the suspension control ECU S14 connector.
(b) Measure the resistance according to the values in the table below.
Standard resistance (Front RH): (C1737/31):
Standard resistance (Front LH): (C1738/32):
Standard resistance (Rear RH): (C1739/33):
Standard resistance (Rear LH): (C1740/34):
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
5. CHECK HARNESS AND CONNECTOR (HEIGHT CONTROL SOLENOID VALVE - BODY GROUND)
(a) Measure the resistance according to the values in the table below.
Standard resistance (Front RH): (C1737/31):
Standard resistance (Front LH): (C1738/32):
Standard resistance (Rear RH): (C1739/33):
Standard resistance (Rear LH): (C1740/34):
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE SUSPENSION CONTROL ECU