Inspection Procedure

NOTE:

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

READ VALUE USING TECHSTREAM (VEHICLE SPEED)

Turn the ignition switch off.
Connect Techstream to the DLC3.
Turn the ignition switch on (IG) and turn the tester on.
Enter the following menus: Chassis/Tire Pressure Monitor/Data List.
Check that the values indicated on the tester and on the combination meter are the same.

Tire Pressure Monitor

TESTER DISPLAY REFERENCE

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Vehicle Speed	Vehicle speed/ min.: 0km/h (0mph) max.: 255 km/h (158 mph)	Almost same as actual vehicle speed	Speed indicated on combination meter

OK:

Vehicle speed indicated on the tester and on the combination meter are the same.

NG: Go to step 2

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

CHECK HARNESS AND CONNECTOR (ECU - COMBINATION METER)

Disconnect the D33 ECU connector.
Disconnect the E1 meter connector.
Measure the resistance according to the value (s) in the table below.

Standard resistance

STANDARD RESISTANCE SPECIFICATION

Tester Connection	Condition	Specified Condition
D33-2 (SPD) - E1-9 (+S)	Always	Below 1 Ω
D33-2 (SPD) - Body ground	Always	10 kΩ or higher

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig 1: Identifying D33 ECU And E1 Meter Connectors

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to next step

INSPECT TIRE PRESSURE WARNING ECU (SPD SIGNAL)

Remove the combination meter (See REMOVAL ).
Reconnect D33 and E1 connectors.
Jack up the vehicle.
Shift the lever to the neutral position.
Turn the ignition switch on (IG).
Check the waveform of the ECU connector using an oscilloscope while turning the wheel slowly.

Result

RESULT REFERENCE

Tester Connection	Switch Condition	Specified Condition
E1-9 (+S) - Body ground	Ignition switch on (IG)	Correct waveform appears as shown

Tool Setting

TOOL SETTING REFERENCE

Item	Contents
Tool Setting	5 V/DIV., 20 ms/DIV.
Vehicle Condition	Driving wheel rotating slowly

OK:

The waveform is displayed as shown in the illustration.

HINT:

When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows.

Fig 2: Identifying E1 Combination Meter Connector

NG: GO TO METER/GAUGE SYSTEM (See SPEED SIGNAL CIRCUIT )

OK: REPLACE TIRE PRESSURE WARNING ECU (See REMOVAL )