Engine Control System - SFI 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

The ECM assumes that the vehicle is being driven, when the indicated engine speed is more than 2000 rpm and 30 seconds have elapsed since the Park/Neutral Position (PNP) switch was turned OFF. If there is no speed signal from the combination meter, despite these conditions being met, 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 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. CHECK OPERATION OF SPEEDOMETER
(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" (Speedometer Malfunction).

NG -- GO TO SPEEDOMETER MALFUNCTION
OK -- Continue to next step.
2. READ VALUE USING TECHSTREAM (VEHICLE SPD)
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Turn the tester on.
(d) Select the following menu items: Powertrain / Engine and ECT / Data List / Vehicle Speed.
(e) Drive the vehicle.
(f) 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.
3. CHECK COMBINATION METER ASSEMBLY (+S VOLTAGE)





(a) Disconnect the combination meter connector.
(b) Turn the ignition switch to the ON position.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:





(d) Reconnect the combination meter connector.
NG -- CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM)
OK -- Continue to next step.
4. CHECK COMBINATION METER ASSEMBLY (SPD SIGNAL WAVEFORM)





(a) Shift the transmission gear selector lever to the neutral position.
(b) Jack up the vehicle.
(c) Turn the ignition switch to the ON position.
(d) Measure the voltage between the terminal of the combination meter and body ground while the wheels are turned slowly.
Standard voltage:





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

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





(a) Disconnect the combination meter connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):





Standard resistance (Check for short):





(d) Reconnect the combination meter connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM