C1774

SUSPENSION CONTROL: AIR SUSPENSION SYSTEM: C1774/74: Power Source Circuit

DTC C1774/74 - Power Source Circuit

DESCRIPTION

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.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK SOURCE VOLTAGE
(a) Check the positive battery voltage.
Standard voltage:
10 to 14 V
NG -- REPLACE BATTERY
OK -- Continue to next step.
2. INSPECT FUSE (AIR SUS NO.2)





(a) Remove the AIR SUS No. 2 fuse and ECU-IG fuse from the instrument panel J/B.
(b) Check fuse.
(1) Check continuity of the AIR SUS No. 2 fuse.
Standard:
Continuity
NG -- REPLACE FUSE
OK -- Continue to next step.
3. INSPECT FUSE (ECU-IG)
(a) Remove the ECU-IG fuse from the instrument panel J/B.
(b) Check fuse.
(1) Check continuity of the ECU-IG fuse.
Standard:
Continuity
Result:






C -- REPLACE FUSE
B -- INSPECT SUSPENSION CONTROL ECU
A -- Continue to next step.
4. INSPECT SUSPENSION CONTROL ECU
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch to the 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 the voltage.
Voltage:
10 to 14 V
NG -- CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - BODY GROUND)
OK -- REPLACE SUSPENSION CONTROL ECU
5. INSPECT SUSPENSION CONTROL ECU





(a) Remove the suspension control ECU with connectors being connected.
(b) Turn the ignition switch to the ON position.
(c) Measure the voltage according to the values in the table below.
Standard voltage:






NG -- CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - BODY GROUND)
OK -- REPLACE SUSPENSION CONTROL ECU
6. CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - BODY GROUND)





(a) Disconnect the suspension control ECU S15 and S16 connectors.
(b) Measure the resistance according to the values in the table below.
Standard resistance:






Result:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE SUSPENSION CONTROL ECU