Speedometer Malfunction

METER / GAUGE / DISPLAY: METER / GAUGE SYSTEM: Speedometer Malfunction
- Speedometer Malfunction

DESCRIPTION

The meter CPU receives vehicle speed signals from this circuit. The speed sensor detects the wheel speed and sends the appropriate signals to the skid control ECU. 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. The meter CPU calculates the vehicle speed converting 4 pulses to 1 revolution.

HINT
Factors that affect the indicated vehicle speed include tire size, tire inflation, and tire wear. The speed indicated on the speedometer has an allowable margin of error. For details about testing and the margin of error, see the reference chart On-Vehicle Inspection.

WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
If the vehicle speed is outside the allowable range when tested, perform the following procedure On-Vehicle Inspection.

HINT
Before starting circuit inspection, check tire size and tire pressure.

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (SPEED METER OPERATION)

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Combination Meter / Active Test.

(e) Check the operation by referring to the table below.

Combination Meter





* *1: for U.S.A.

* *2: except U.S.A.

OK:

Speedometer indication is normal.

NG -- REPLACE COMBINATION METER ASSEMBLY Removal
OK -- Continue to next step.

2. CHECK BRAKE CONTROL SYSTEM

(a) Check if brake control system DTC is output.

Result:





B -- READ VALUE USING TECHSTREAM (VEHICLE SPEED METER, FL/FR/RL/RR WHEEL SPEED)

A -- REPLACE COMBINATION METER ASSEMBLY Removal

3. READ VALUE USING TECHSTREAM (VEHICLE SPEED METER, FL/FR/RL/RR WHEEL SPEED)

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Enter the following menus:

(1) for Combination Meter: Body Electrical / Combination Meter / Data List.

(2) for ABS/VSC/TRAC: Chassis / ABS/VSC/TRAC / Data List.

(e) Check the values by referring to the values in the table below.

Combination Meter





ABS/VSC/TRAC





OK:

When the Data List values of the ECUs match, an internal malfunction of the combination meter assembly is suspected.

NG:

When the Data List values of the ECUs do not match, a signal output error of the skid control ECU or an internal malfunction of the combination meter assembly is suspected.

NG -- INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE)

OK -- GO TO BRAKE CONTROL SYSTEM How to Proceed With Troubleshooting

4. INSPECT COMBINATION METER ASSEMBLY (OUTPUT VOLTAGE)

(a) Disconnect the A58 connector.





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

Standard Voltage:





Text in Illustration





NG -- CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - SKID CONTROL ECU)
OK -- Continue to next step.

5. INSPECT SKID CONTROL ECU (INPUT WAVEFORM)

(a) Check the input signal waveform.





(1) Remove the combination meter assembly with connector(s) still connected.

(2) Reconnect the A58 connector.

(3) Reconnect the J34 connector.

(4) Connect the oscilloscope to the terminals J34-17 (SI) and body ground.

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

(6) Turn the drive wheel slowly.

(7) Check the signal waveform according to the condition(s) in the table below.





OK:

The waveform is displayed as shown in the illustration.

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

Text in Illustration





NG -- REPLACE SKID CONTROL ECU Removal

OK -- REPLACE COMBINATION METER ASSEMBLY Removal

6. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - SKID CONTROL ECU)

(a) Disconnect the J34 and A58 connectors.





(b) 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 -- REPLACE COMBINATION METER ASSEMBLY Removal