Toyota Tundra. Manual — part 704

Fig. 14: Identifying A28 Security Horn Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to Next Step

7. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - SECURITY HORN RELAY)

a. Remove the security horn relay from the engine room relay block.

b. Disconnect the J1 main body ECU connector.

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

Standard resistance

MAIN BODY ECU - SECURITY HORN RELAY

Tester Connection

Condition

Specified

Condition

Engine room relay block security horn relay terminal 2- J1 -6

(SH)

Always

Below 1 ohms

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Theft Deterrent - Tundra

Fig. 15: Identifying J1 Main Body ECU Connector
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE MAIN BODY ECU

IGNITION SWITCH CIRCUIT

DESCRIPTION

The main body ECU determines the ignition switch position (OFF, ON, ACC or engine running) based on
signals from the IG circuit.

WIRING DIAGRAM

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Theft Deterrent - Tundra

Fig. 16: Ignition Switch - Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

INSPECTION PROCEDURE

1. READ VALUE OF TECHSTREAM (IGNITION SWITCH)

Using Techstream, read the Data List.

Techstream

Main Body

TECHSTREAM MAIN BODY REFERENCE CHART

OK: When the ignition switch is operated, "ON" is displayed on the Techstream screen.

NG: Go to step 2

OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS
TABLE

Tester Display Measurement Item/Range

Normal Condition

Diagnostic Note

IG SW

Ignition switch / ON or OFF

ON: Ignition switch ON
OFF: Ignition switch OFF

-

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Theft Deterrent - Tundra

2. INSPECT FUSE (AM1, ECU-IG No. 2)

a. Remove the AM1 and ECU-IG No. 2 fuses from the main body ECU.

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

Standard resistance

FUSE (AM1, ECU-IG No. 2)

NG: REPLACE FUSE

OK: Go to Next Step

3. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - BATTERY)

a. Disconnect the DA main body ECU connector.

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

Standard voltage

MAIN BODY ECU - BATTERY

Fig. 17: Identifying DA Main Body ECU Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

Tester Connection Condition Specified Condition

AM1 fuse

Always

Below 1 ohms

ECU-IG No. 2 fuse

Tester Connection

Condition Specified Condition

DA-1 (IG) - Body ground Always

11 to 14 V

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Theft Deterrent - Tundra