ECU Power Source Circuit

TIRE AND WHEEL: TIRE PRESSURE WARNING SYSTEM: ECU Power Source Circuit

ECU Power Source Circuit

DESCRIPTION

This is the power source for the tire pressure warning ECU.

WIRING DIAGRAM





INSPECTION PROCEDURE
NOTE: It is necessary to register the transmitter IDs after replacing a tire pressure warning valve and transmitter and/or the tire pressure warning ECU Programming and Relearning.

PROCEDURE

1. INSPECT FUSE (ECU-IG1)
(a) Remove the ECU-IG1 fuse from the instrument panel junction block.
(b) Measure the resistance of the fuse.
Standard resistance:
Below 1 Ohms
NG -- REPLACE FUSE
OK -- Continue to next step.
2. INSPECT IG1 RELAY





(a) Remove the IG1 relay from the instrument panel junction block.
(b) Measure the resistance of the relay.
Standard resistance:






NG -- REPLACE IG1 RELAY
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (ECU - BATTERY AND BODY GROUND)





(a) Disconnect the E56 ECU connector.
(b) Measure the voltage of the wire harness side connector.
Standard voltage:





(c) Measure the resistance of the wire harness side connector.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE