Toyota Tundra. Manual — part 2777

DTC C2178/78: BATTERY VOLTAGE MALFUNCTION

DESCRIPTION

DTC DETECTION CONDITION TABLE

INSPECTION PROCEDURE

If DTC C2178/78 is output, inspect the battery and charging system for 1GR-FE (See ON-VEHICLE
INSPECTION ), 2UZ-FE (See ON-VEHICLE INSPECTION ) or 3UR-FE (See ON-VEHICLE
INSPECTION ). If the battery and charging system are normal, perform INSPECTION PROCEDURE .

TIRE PRESSURE WARNING RESET SWITCH CIRCUIT

DESCRIPTION

The tire pressure warning ECU enters the initialization mode and performs initialization automatically. Then it
receives the signal from the tire pressure warning reset switch. If the ECU receives the signal, the tire pressure
warning light blinks 3 times (1 second on, 1 second off).

WIRING DIAGRAM

Fig. 32: Tire Pressure Warning Reset Switch Circuit - Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

INSPECTION PROCEDURE

DTC

Code

DTC Detection Condition

Trouble Area

C2178/78

With ignition switch ON, when IG voltage of less than 10 V continues
for 20 minutes or more, or IG voltage of over 16 V continues for 0.5
seconds or more



Battery



Charging system



Tire pressure
warning ECU

2009 Toyota Tundra

2009 SUSPENSION Tire & Wheel - Tundra

1. CHECK TIRE PRESSURE WARNING RESET SWITCH FUNCTION

a. Perform the tire pressure warning reset switch test in TEST MODE PROCEDURE ).

OK

SWITCH CONDITION SPECIFIED CONDITION TABLE

NG: Go to step 2

OK: USE SIMULATION METHOD TO CHECK (See HOW TO PROCEED WITH
TROUBLESHOOTING )

2. INSPECT TIRE PRESSURE WARNING RESET SWITCH

a. Remove the tire pressure warning reset switch (See REMOVAL ).

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

Standard Resistance

TESTER CONNECTION SPECIFIED CONDITION TABLE

NOTE:



When replacing the tire pressure warning ECU, read the transmitter IDs
stored in the old ECU using the Techstream and note down before
removal.



It is necessary to perform INITIALIZATION after REGISTRATION of the
transmitter IDs into the tire pressure warning ECU, after the ECU and/or
tire pressure warning valve and transmitter has been replaced.

Switch Condition

Specified Condition

Tire pressure warning reset switch on Tire pressure warning light turns on.
Tire pressure warning reset switch off Tire pressure warning light blinks.

Tester Connection

Switch Condition

Specified Condition

1 - 2

ON (Switch is pressed and held)

Below 1 ohms

OFF (Switch is not pressed)

10 kohms or higher

2009 Toyota Tundra

2009 SUSPENSION Tire & Wheel - Tundra

Fig. 33: View Of Tire Pressure Warning Reset Switch
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

NG: REPLACE TIRE PRESSURE WARNING RESET SWITCH (See REMOVAL )

OK: Go to next step

3. CHECK HARNESS AND CONNECTOR (RESET SWITCH - ECU AND BODY GROUND)

a. Disconnect the J43 reset switch connector.

b. Disconnect the J31 ECU connector.

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

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION TABLE

Tester Connection

Condition Specified Condition

J31-1 (CLSW) - J43-1

Always

Below 1 ohms

J31-1 (CLSW) - Body ground Always

10 kohms or higher

J43-2 - Body ground

Always

Below 1 ohms

2009 Toyota Tundra

2009 SUSPENSION Tire & Wheel - Tundra

Fig. 34: Identifying J43 Reset Switch Connector & J31 ECU Connector
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE TIRE PRESSURE WARNING ECU (See REMOVAL )

TIRE PRESSURE WARNING LIGHT CIRCUIT

DESCRIPTION

If the tire pressure warning ECU detects a disconnected connector or an open circuit between the tire pressure
warning ECU and combination meter, the tire pressure warning light turns off 10 seconds after the ignition
switch is turned ON, blinks for 1 minute, and then remains on. Connecting terminals TC and CG of the DLC3
makes the tire pressure warning light blink and output the DTC.

WIRING DIAGRAM

2009 Toyota Tundra

2009 SUSPENSION Tire & Wheel - Tundra