P0503

CRUISE CONTROL: CRUISE CONTROL SYSTEM: P0500/21: Vehicle Speed Sensor Circuit

DTC P0500/21 - Vehicle Speed Sensor Circuit

DTC P0503/23 - Vehicle Speed Sensor Circuit

DESCRIPTION

Vehicles, which are equipped with ABS (Anti-Lock Brake System), detect the vehicle speed using the skid control ECU and wheel speed sensor. The wheel speed sensor monitors the wheel rotation speed and sends a signal to the skid control ECU. The skid control ECU converts the wheel speed signal into a 4-pulse signal and transmits it to the ECM via the combination meter. The ECM determines the vehicle speed based on the frequency of the pulse signal.









MONITOR DESCRIPTION

Automatic Transaxle Models:
The ECM assumes that the vehicle is being driven when the transmission counter gear indicates more than 300 rpm and over 30 seconds have passed since the Park/Neutral Position (PNP) switch was turned OFF. If there is no signal from the vehicle speed sensor, despite these conditions being met, the ECM interprets this as a malfunction in the sensor. The ECM then illuminates the MIL and sets the DTC.
Manual Transaxle Models:
The ECM assumes that the vehicle is being driven while the vehicle speed sensor signal is being transmitted by the combination meter. If there is no signal from the No. 1 vehicle speed sensor despite this condition being met, the ECM interprets this as a malfunction in the sensor. The ECM then illuminates the MIL and sets the DTC.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





M/T:





A/T:





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 be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

PROCEDURE

1. CHECK OPERATION OF SPEEDOMETER
(a) Drive the vehicle and check if 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.

NG -- CHECK SPEEDOMETER CIRCUIT
OK -- Continue to next step.
2. INSPECT ECM (SPD VOLTAGE)




(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 according to the value(s) in the table below as the wheel is turned slowly.
Standard voltage:





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

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM