Up to 08/2009

TIRE PRESSURE MONITORING: TIRE PRESSURE WARNING SYSTEM: C2191/91: Vehicle Speed Signal Error (Test Mode DTC)
C2191/91 - Vehicle Speed Signal Error (Test Mode DTC)

DESCRIPTION

The tire pressure warning ECU receives a vehicle speed signal from the combination meter. This DTC is stored upon entering test mode, and cleared when a vehicle speed signal of 20 km/h (12 mph) is detected for 3 seconds or more. This DTC is output only in test mode.

HINT
The meter CPU receives vehicle speed signals from this circuit. The vehicle speed sensor detects the voltage that varies according to the vehicle speed. The skid control ECU supplies power to the vehicle speed sensor. The skid control ECU detects vehicle speed signals based on the pulses of the voltage. The skid control ECU transmits vehicle speed signals as pulses to the meter CPU. A voltage of 12 V is output from the combination meter assembly and then input to the skid control ECU. The signal is changed to a pulse signal at the transistor in the combination meter assembly. A voltage of 12 V or 5 V is output from each ECU or relay and then input to the combination meter assembly. Each ECU controls the respective system based on the pulse signal.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
- 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 Initialization after registration Registration of the transmitter IDs into the tire pressure warning ECU if the ECU has been replaced.
PROCEDURE

1. READ VALUE USING TECHSTREAM (VEHICLE SPEED)

(a) Turn the engine switch off.

(b) Connect Techstream to the DLC3.

(c) Turn the engine switch on (IG) and turn the tester on.

(d) Enter the following menus: Chassis / Tire Pressure Monitor / Data List.

(e) Check that the values indicated on the tester and on the combination meter are the same.

Tire Pressure Monitor





OK:

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

NG -- CHECK HARNESS AND CONNECTOR (ECU - COMBINATION METER)

OK -- USE SIMULATION METHOD TO CHECK How To Proceed With Troubleshooting

2. CHECK HARNESS AND CONNECTOR (ECU - COMBINATION METER)

(a) Disconnect the F53 ECU connector.





(b) Disconnect the F15 meter connector.

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

Standard resistance:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

3. INSPECT TIRE PRESSURE WARNING ECU (SPD SIGNAL)

(a) Remove the combination meter Removal.





(b) Reconnect F53 and F15 connectors.

(c) Jack up the vehicle.

(d) Shift the lever to the neutral position.

(e) Turn the engine switch on (IG).

(f) Check the waveform of the ECU connector using an oscilloscope while turning the wheel slowly.

Result:





Tool Setting





OK:

The waveform is displayed as shown in the illustration.

Text in 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.

NG -- GO TO METER / GAUGE SYSTEM

OK -- REPLACE TIRE PRESSURE WARNING ECU