C1779

SUSPENSION CONTROL: AIR SUSPENSION SYSTEM: C1779/79: Crankshaft Position Sensor Circuit

DTC C1779/79 - Crankshaft Position Sensor Circuit

DTC C1797/97 - Crankshaft Position Sensor Circuit

DESCRIPTION

The suspension control ECU receives the engine speed signal from ECM.





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

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - ECM)
(a) Check for open and short circuit in the harness and the connector between the suspension control ECU and ECM Electronic Circuit Inspection Procedure.
NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
2. INSPECT ECM (TACH SIGNAL)




(a) Remove the ECM with connectors being connected.
(b) Turn the ignition switch ON.
(c) Connect an oscilloscope to terminals E8-1 (TACH) and E7-1 (E1) of the ECM harness side connector.




(d) With the engine idling, check the signal waveform.
Standard:
Signal waveform appears as shown in the illustration.
HINT: As the engine speed becomes higher, the waveform cycle gets shorter.

NG -- REPLACE ECM
OK -- REPLACE SUSPENSION CONTROL ECU