Main Power Supply and Ground Circuit Testing
TROUBLE DIAGNOSIS FOR POWER SUPPLYAT - MAIN:
TCM TERMINALS AND REFERENCE VALUE:
Diagnostic Procedure
1. CHECK TCM POWER SOURCE
1. Turn ignition switch to ON position.
(Do not start engine.)
2. Check voltage between TCM harness connector M77 terminals 10 (W/R), 19 (W/R) and ground.
Voltage:............Battery voltage
3. Turn ignition switch to OFF position.
4. Check voltage between TCM harness connector M78 terminal 28 (R/Y) and ground.
Voltage: Battery voltage
OK or NG?
OK >> GO TO 2.
NG >> Check the following items:
- Harness for short or open between ignition switch and TCM terminals 10, 19 and 28 (Main harness)
- Ignition switch and fuse.
2. CHECK TCM GROUND CIRCUIT
1. Turn ignition switch to OFF position.
2. Disconnect TCM harness connector.
3. Check continuity between terminals (25, 48) and ground. Refer to "Wiring Diagram AT-MAIN"
Continuity should exist.
If OK, check harness for short to ground and short to power.
OK or NG?
OK >>INSPECTION END.
NG >>Repair open circuit or short to ground or short to power in harness or connectors.