ECU Power Source Circuit

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

ECU Power Source Circuit

DESCRIPTION

This circuit supplies power to the tire pressure warning ECU. The power is also supplied to the tire pressure warning antenna and receiver via the ECU.
Operation of the tire pressure warning system is terminated when this circuit has a malfunction. At this time, the tire pressure warning light on the combination meter will come on.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT BATTERY
(a) Check the battery voltage.
Standard voltage:
11 to 14 V
NG -- CHECK AND REPLACE CHARGING SYSTEM
OK -- Continue to next step.
2. INSPECT FUSE (ECU-IG NO. 1)





(a) Remove the ECU-IG No. 1 fuse from the instrument panel J/B.
(b) Check continuity of the ECU-IG No. 1 fuse.
Standard:
Continuity exists.
NG -- REPLACE ECU-IG NO. 1 FUSE
OK -- Continue to next step.
3. INSPECT TIRE PRESSURE WARNING ECU





(a) Remove the tire pressure warning ECU with the connectors still connected.
(b) Turn the ignition switch to the ON position.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- CHECK HARNESS AND CONNECTOR (BATTERY - TIRE PRESSURE WARNING ECU)
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
4. CHECK HARNESS AND CONNECTOR (BATTERY - TIRE PRESSURE WARNING ECU)





(a) Disconnect the tire pressure warning ECU T23 connector.
(b) Turn the ignition switch to the ON position.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
5. CHECK HARNESS AND CONNECTOR (TIRE PRESSURE WARNING ECU - BODY GROUND)





(a) Disconnect the tire pressure warning ECU T23 connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE TIRE PRESSURE WARNING ECU