Engine Control System

2AZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0500: Vehicle Speed Sensor "A"

DTC P0500 - Vehicle Speed Sensor "A"

DESCRIPTION

The speed sensor detects the wheel speed and sends the appropriate signals to the skid control ECU. The skid control ECU converts these wheel speed signals into a 4-pulse signal and outputs it to the ECM via the combination meter. The ECM determines the vehicle speed based on the frequency of these pulse signals.

MONITOR DESCRIPTION

If there is no speed signal from the combination meter even though the ECM determines that the vehicle is being driven, the ECM interprets this as a malfunction in the speed signal circuit. The ECM then illuminates the MIL and sets the DTC.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

Automatic transmission:

Manual transmission:

TYPICAL MALFUNCTION THRESHOLDS

WIRING DIAGRAM

INSPECTION PROCEDURE
HINT: Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

1. READ VALUE USING TECHSTREAM (VEHICLE SPEED)
(a) Drive the vehicle and check whether the operation of the speedometer in the combination meter is normal.
HINT:
- The vehicle speed sensor is operating normally if the speedometer reading is normal.
- If the speedometer does not operate, check it by following the procedure described in speedometer malfunction.
(b) Connect the Techstream to the DLC3.
(c) Turn the ignition switch to the ON position.
(d) Turn the tester on.
(e) Select the following menu items: Powertrain / Engine and ECT / Data List / Vehicle Speed.
(f) Drive the vehicle.
(g) Read the value displayed on the tester.
OK:
Vehicle speeds displayed on tester and speedometer display are equal.
OK -- CHECK FOR INTERMITTENT PROBLEMS
NG -- Continue to next step.
2. CHECK COMBINATION METER ASSEMBLY (SPD SIGNAL WAVEFORM)

(a) Inspect the combination meter using an oscilloscope.
(1) Shift the transmission gear selector lever to the neutral position.
(2) Jack up the vehicle.
(3) Turn the ignition switch to the ON position.
(4) Measure the voltage between the terminal of the combination meter and body ground while the wheel is turned slowly.
Standard voltage:

HINT: The output voltage should fluctuate up and down, similarly to the diagram, when the wheel is turned slowly.

NG -- CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM)
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM)

(a) Disconnect the F2 combination meter connector.
(b) Disconnect the A24 ECM connector.
(c) Measure the resistance between the terminals of the wire harness side connectors.
Standard resistance (Check for open):

(d) Reconnect the combination meter connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM
4. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM)

(d) Reconnect the combination meter connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- GO TO SPEED SIGNAL CIRCUIT