Toyota Tundra Service Manual: IG Power Source Circuit

DESCRIPTION

When the ignition switch is turned ON, positive (+) battery voltage is applied to the air conditioning amplifier.

WIRING DIAGRAM

PROCEDURE

1.	INSPECT FUSE (ECU-IG1 NO.3)

(a) Remove the ECU-IG1 NO.3 fuse from the driver side junction block.

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

Standard resistance:

Tester Connection	Condition	Specified Condition
ECU-IG1 NO.3 fuse	Always	Below 1 Ω

REPLACE FUSE

2.	CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BATTERY AND BODY GROUND)

(a) Disconnect the J19 air conditioning amplifier connector.

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

Standard resistance:

Tester Connection	Condition	Specified Condition
J19-14 (GND) - Body ground	Always	Below 1 Ω

Standard voltage:

Tester Connection	Switch Condition	Specified Condition
J19-1 (IG+) - Body ground	Ignition switch ON	11 to 14 V

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

REPAIR OR REPLACE HARNESS OR CONNECTOR

Toyota Tundra Service Manual > Occupant Classification System: Front Occupant Classification Sensor LH Circuit Malfunction (B1780)
DESCRIPTION The front occupant detection sensor LH circuit consists of the occupant classification ECU and the front occupant detection sensor LH. DTC B1780 is set when a malfunction is detected in the front occupant detection sensor LH circuit. DTC Code DTC Detection Condition Trouble Area B1780 On ...

Toyota Tundra Owners Manual