Up to 08/2009

SUSPENSION CONTROL: AIR SUSPENSION SYSTEM: C1751: Compressor Relay Coil Malfunction
C1751 - Compressor Relay Coil Malfunction

DESCRIPTION

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





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
- Before performing troubleshooting, inspect the connectors of related circuits.
- If DTC C1782 (Power Source Voltage Malfunction) is output at the same time, perform troubleshooting for C1782 first C1782.
- Before replacing the suspension control ECU, perform all of the following again: 1) symptom simulation How To Proceed With Troubleshooting; 2) DTC inspection Reading and Clearing Diagnostic Trouble Codes; and 3) Techstream inspection (Data List or Active Test) Scan Tool Testing and Procedures. If no malfunctions are found in other areas, replace the suspension control ECU.
- If the suspension control ECU is replaced, the vehicle height offset calibration and registration of vehicle identification information must be performed Calibration and Registration)
PROCEDURE

1. INSPECT AIR SUS RELAY

(a) Turn the engine switch off.

(b) Remove the AIR SUS relay from the engine room J/B.





(c) Measure the resistance according to the value(s) in the table below.

Standard resistance:





NG -- REPLACE AIR SUS RELAY
OK -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (AIR SUS RELAY - ECU AND BODY GROUND)

(a) Disconnect the A54 ECU connector.

(b) Remove the AIR SUS relay from the engine room J/B.





(c) Measure the resistance according to the value(s) in the table below.

Standard resistance:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE SUSPENSION CONTROL ECU