Toyota Tundra Service Manual: ECU Power Source Circuit

DESCRIPTION

The IG circuit is the power source for the tire pressure warning ECU and receiver.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When replacing the tire pressure warning ECU and receiver, read the transmitter IDs stored in the old ECU using the Techstream and write them down before removal.
It is necessary to perform initialization after registration of the transmitter IDs into the tire pressure warning ECU and receiver if the ECU has been replaced.

HINT:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (TIRE PRESSURE WARNING ECU AND RECEIVER POWER SOURCE)

(a) Disconnect the P21 tire pressure warning ECU and receiver connector.

*a	Front view of wire harness connector (to Tire Pressure Warning ECU and Receiver)

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection	Condition	Specified Condition
P21-1 (IG) - Body ground	Ignition switch ON	11 to 14 V
P21-1 (IG) - Body ground	Ignition switch OFF	Below 1 V

Standard Resistance:

Tester Connection	Condition	Specified Condition
P21-12 (GND) - Body ground	Always	Below 1 Ω

REPLACE TIRE PRESSURE WARNING ECU AND RECEIVER

REPAIR OR REPLACE HARNESS OR CONNECTOR

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Toyota Tundra Owners Manual