Toyota 4Runner: Diagnosis System

Toyota 4Runner Service Manual / Suspension / Tire Pressure Monitoring / Tire Pressure Warning System / Diagnosis System

DIAGNOSIS SYSTEM

1. CHECK WARNING LIGHT

NOTICE:

When there is a problem with the tire pressure warning system, the tire pressure warning light blinks at 0.5 second intervals and comes on after 1 minute.
When the malfunction has been corrected, the tire pressure warning light does not come on.
When the tire pressure warning light comes on, immediately check the tire pressures of the tires and adjust them to the specified value(s).
After the ignition switch is turned to ON, the tire pressure warning light comes on or 3 seconds and then turns off. If the warning light does not come on for 3 seconds, proceed to troubleshooting for the tire pressure warning light circuit (See page ).

(a) Turn the ignition switch to ON.

(b) Check that the tire pressure warning light illuminates for 3 seconds.

2. HOW TO PROCEED WHEN TIRE PRESSURE WARNING LIGHT COMES ON

(a) When the tire pressure warning light does not go off, or when it comes on during driving, check the tire pressure. If the tire pressure warning light comes on within several hours after adjusting the tire pressure, the tire may have a slow air leak.

(b) The system does not operate under the following conditions (when the problem is corrected, operation returns to normal).

(1) Tires without a tire pressure warning valve and transmitter are used.

(2) A tire pressure warning valve and transmitter ID is not registered in the ECU.

(3) The tire pressure is abnormally high (absolute pressure: 600 kPa (6.1 kgf/cm2, 87 psi) or higher; relative pressure: 500 kPa (5.1 kgf/cm2, 73 psi) or higher).

(4) The battery voltage of the tire pressure warning valve and transmitter has dropped (battery life: 10 years).

(c) The system may not operate under the following conditions (when the problem is corrected, operation returns to normal).

(1) Facilities or devices that use similar radio frequencies are located in the vicinity of the vehicle.

(2) A radio device of similar frequencies is used in the vehicle.

(3) A type of film that affects radio waves is attached to the windows.

(4) A large amount of snow or ice is stuck to the vehicle, especially onto the wheels and around the wheel houses.

(5) Any wheels other than the specified ones are used.

(6) Tire chains are used.

(7) A large metallic object which can interfere with signal reception is put in the luggage room.

3. TIRE PRESSURE WARNING LIGHT AND INDICATOR CHART

HINT:

The table below indicates the state of the tire pressure warning light after the ignition switch is turned to ON.

Condition	Immediately after turning ignition switch to ON	Always
	Immediately after turning ignition switch to ON	Warning light output pattern
	Comes on for 3 seconds	Goes off	Comes on	Blinks for 1 minute and then illuminates*1	Blinks*2	Blinks*3	DTC output
Normal	○	○	-	-	-	-	-
Low tire pressure	○	-	○	-	-	-	-
System failure	○	-	-	○	-	-	-
Test mode (signal check mode)	○	-	-	-	○	-	-
ECU connector poorly connected	-	-	-	○*4	-	-	-
TC ground (DTC is output)	○	-	-	-	-	-	○
TC ground (DTC is not output)	○	-	-	-	-	○	-

*1: Comes on and goes off repeatedly at 0.5 second intervals and turns on after 1 minute.
*2: Comes on and goes off repeatedly at 0.125 second intervals.
*3: Comes on and goes off repeatedly at 0.25 second intervals.
*4: When there is an open circuit, the light is off for 10 seconds. Then it blinks at 0.5 second intervals and turns on after 1 minute.

4. NORMAL MODE DTC

(a) DTCs are stored in the tire pressure warning ECU and are output by the blinking of the tire pressure warning light or by using the Techstream (See page ).

5. TEST MODE (SIGNAL CHECK MODE) DTC

(a) By switching from normal mode into test mode (signal check mode) (input signal check), it is possible to inspect the tire pressure warning antenna and receiver, each tire pressure warning valve and transmitter and each vehicle speed sensor (See page ).

6. FAIL-SAFE FUNCTION

(a) When a system malfunction occurs in the tire pressure warning system, the tire pressure warning light comes on after blinking for 1 minute and informs the driver of the system failure.

(b) Diagnostic trouble codes are stored in the tire pressure warning ECU when malfunctions occur.

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