FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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P0500

Vehicle Speed Sensor Circuit:




Connectors:





CIRCUIT OPERATION
- A 5-volt voltage is applied to the vehicle speed sensor output terminal (terminal No.3) from the ECM (terminal No.80). The vehicle speed sensor generates a pulse signal when the output terminal is opened and grounded.

TECHNICAL DESCRIPTION
- The vehicle speed sensor converts the vehicle speed into pulse signals and inputs them to the ECM.
- The vehicle speed sensor outputs a pulse signal while the vehicle is driven.
- The ECM checks whether the pulse signal is output.

DTC SET CONDITIONS

Check Conditions
- 2 seconds or more have passed the starting sequence was completed.
- Engine speed is at between 2,100 and 4,000 rpm.
- Volumetric efficiency is at between 40 and 70 percent.

Judgement Criteria
- Vehicle speed sensor output voltage has not changed (no pulse signal is input) for 2 seconds.

TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Vehicle speed sensor failed.
- Open or shorted vehicle speed sensor circuit, or loose connector.
- ECM failed.

DIAGNOSIS

Required Special Tool:
- MB991502: Scan Tool (MUT-II)





STEP 1. Using scan tool MB991502, check data list item 24: Vehicle Speed Sensor.

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF.) position before connecting or disconnecting scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector.
2. Start the engine.
3. Set scan tool MB991502 to the data reading mode for item 24, Vehicle Speed Sensor.
- Check that the speedometer and MUT-II display speed match when traveling at a vehicle speed of 40 km/h (25 mph).
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the sensor operating properly?

YES: It can be assumed that this malfunction is intermittent.
Refer to INTRODUCTION, How to Use Troubleshooting/Inspection Service Points.
NO: Go to Step 2.

STEP 2. Check speed meter.

Q: Is the speed meter functioning?

YES: Go to Step 3.
NO: Go to Step 8.











STEP 3. Using the oscilloscope, check the sensor output voltage at ECM connector C-122.

1. Do not disconnect the ECM connector C-122.
2. Disconnect the combination meter connector and auto- cruise control-ECU connector.
3. Connect the oscilloscope probe to terminal No.80 of the ECM by backprobing.
4. Start the engine.
5. Check the waveform.
- The waveform should show a pattern similar to the illustration while the vehicle is being moved.
6. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the waveform normal?

YES: Go to Step 4.
NO: Go to Step 6.





STEP 4. Check connector C-122 at ECM for damage.

Q: Is the connector in good condition?

YES: Go to Step 5.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 17.





STEP 5. Using scan tool MB991502, check data list item 24: Vehicle Speed Sensor.

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector.
2. Start the engine.
3. Set scan tool MB991502 to the data reading mode for item 24, Vehicle Speed Sensor.
- Check that the speedometer and MUT-II display speed match when traveling at a vehicle speed of 40 km/h (25 mph).
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the sensor operating properly?

YES: It can be assumed that this malfunction is intermittent. Refer to INTRODUCTION, How to Use Troubleshooting/Inspection Service Points.
NO: Replace the ECM. Then go to Step 17.








STEP 6. Measure the sensor supply voltage at ECM connector C-122 by backprobing.

1. Do not disconnect the ECM connector C-122.
2. Disconnect the vehicle speed sensor connector B-109.
3. Turn the ignition switch to the "ON" position.
4. Measure the voltage between terminal No.80 and ground by backprobing.
- Voltage should be between 4.8 and 5.2 volts.
5. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the measured voltage between 4.8 and 5.2 volts?

YES: Go to Step 7.
NO: Replace the ECM. Then go to Step 17.





STEP 7. Check connector C-122 at ECM for damage.

Q: Is the connector in good condition?

YES: Check connector B-106 at intermediate connector for damage, and repair or replace as required. Refer to Harness Connector Inspection. If intermediate connector is in good condition, repair harness wire between vehicle speed sensor connector B-109 (terminal No.3) and ECM connector C-122 (terminal No.80) because of open circuit. Then go to Step 17.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 17.





STEP 8. Check connector B-109 at vehicle speed sensor for damage.

Q: Is the connector in good condition?

YES: Go to Step 9.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 17.








STEP 9. Measure the power supply voltage at vehicle speed sensor harness side connector B-109.

1. Disconnect the connector B-109 and measure at the harness side.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No.1 and ground.
- Voltage should be battery positive voltage.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is battery positive voltage (approximately 12 volts) present?

YES: Go to Step 10.
NO: Check connectors B-106, C-25, C-141, C-312 and C-311 at intermediate connector for damage, and repair or replace as required. Refer to Harness Connector Inspection. If intermediate connectors are in good condition, repair harness wire between ignition switch connector C-202 (terminal No.2) and vehicle speed sensor connector B-109 (terminal No.1) because of open circuit or short circuit to ground. Then go to Step 17.








STEP 10. Check the continuity at vehicle speed sensor harness side connector B-109.

1. Disconnect the connector B-109 and measure at the harness side.
2. Check for the continuity between terminal No.2 and ground.
- Should be less than 2 ohms.

Q: Is the continuity normal?

YES: Go to Step 11.
NO: Check connector B-106 at intermediate connector for damage, and repair or replace as required. Refer to Harness Connector Inspection. If intermediate connector is in good condition, repair harness wire between vehicle speed sensor connector B-109 (terminal No.2) and ground because of open circuit or harness damage. Then go to Step 17.








STEP 11. Measure the sensor supply voltage at vehicle speed sensor harness side connector B-109.

1. Disconnect the vehicle speed sensor connector B-109 and measure at the harness side.
2. Disconnect the combination meter connector and auto-cruise control-ECU connector.
3. Turn the ignition switch to the "ON" position.
4. Measure the voltage between terminal No.3 and ground.
- Voltage should be between 4.8 and 5.2 volts.
5. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the measured voltage between 4.8 and 5.2 volts?

YES: Go to Step 12.
NO: Check connector B-106 at intermediate connector for damage, and repair or replace as required. Refer to Harness Connector Inspection. If intermediate connector is in good condition, repair harness wire between vehicle speed sensor connector B-109 (terminal No.3) and ECM connector C-122 (terminal No.80) because of short circuit to ground or harness damage. Then go to Step 17.

STEP 12. Check the vehicle speed sensor.
Refer to Instrument Panel Systems - Combination Metre - Vehicle Speed Sensor Check.

Q: Is the vehicle speed sensor normal?

YES: Go to Step 13.
NO: Replace the vehicle speed sensor. Then go to Step 17.





STEP 13. Check connector C-122 at ECM for damage.

Q: Is the connector in good condition?

YES: Go to Step 14.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 17.





STEP 14. Check for harness damage between ignition switch connector C-202 (terminal No.2) and vehicle speed sensor connector B-109 (terminal No.1).

NOTE: Check harness after checking intermediate connectors B-106, C-25, C-141, C-312 and C-311. If intermediate connectors are damaged, repair or replace them. Refer to Harness Connector Inspection. Then go to Step 17.

Q: Is the harness wire in good condition?

YES: Go to Step 15.
NO: Repair it. Then go to Step 17.





STEP 15. Check for harness damage between vehicle speed sensor connector B-109 (terminal No.3) and ECM connector C-122 (terminal No.80).

NOTE: Check harness after checkThg intermediate connector B-106 If intermediate connector is damaged, repair or replace them. Refer to Harness Connector Inspection. Then go to Step 17.

Q: Is the harness wire in good condition?

YES: Go to Step 16.
NO: Repair it. Then go to Step 17.





STEP 16. Check for harness damage between vehicle speed sensor connector B-109 (terminal No.2) and ground.

NOTE: Check harness after checking intermediate connector B-106 If intermediate connector is damaged, repair or replace them. Refer to Harness Connector Inspection. Then go to Step 17.

Q: Is the harness wire in good condition?

YES: Check for harness wire between vehicle speed sensor connector B-109 (terminal No.3) and other system because of short circuit to ground. Then go to Step 17.
NO: Repair it. Then go to Step 17.





STEP 17. Using scan tool MB991502, check data list item 24: Vehicle Speed Sensor.

CAUTION
To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector.
2. Start the engine.
3. Set scan tool MB991502 to the data reading mode for item 24, Vehicle Speed Sensor.
- Check that the speedometer and MUT-II display speed match when traveling at a vehicle speed of 40 km/h (25 mph).
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the sensor operating properly?

YES: The inspection is complete.
NO: Retry the troubleshooting.