DTC 29: Vehicle Speed Sensor System: Diagnosis
Required Special Tool:
- MB991502: Scan Tool (MUT-II)
- STEP 1. Check the speedometer.
Q: Is the speedometer operating properly?
YES: Go to Step 2.
NO: Check the vehicle speed sensor. Refer to Combination Meters Assembly and Vehicle Speed Sensor - How to Use Troubleshooting/Inspection Service Points - ON-VEHICLE SERVICEINSPECTION .
- STEP 2. Using scan tool MB991502, check data list item 29: Vehicle Speed Sensor. CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
- Connect scan tool MB991502 to the data link connector.
- Start the engine.
- Set scan tool MB991502 to data-reading mode for item 29, Vehicle Speed Sensor.
- Check that the speedometer and scan tool display speed match when driving at a vehicle speed of 40 km/h (25 mph).
- 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 How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .
NO: Go to Step 3.
- STEP 3. Using an oscilloscope, check the vehicle speed sensor waveform at PCM connector C-91 by backprobing.
- Do not disconnect connector C-91.
- Connect an oscilloscope probe to PCM connector C-91 terminal 80 by backprobing.
- Start the engine.
- Check the vehicle speed sensor waveform.
- The vehicle speed sensor waveform should show a pattern similar to the illustration when running the vehicle.
- Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the waveform normal?
YES: Go to Step 6.
NO: Go to Step 4.
- STEP 4. Check PCM connector C-91 and intermediate connector C-16 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Q: Are the connectors and terminals in good condition?
YES: Go to Step 5.
NO: Repair or replace the damaged components. Refer to How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .
- STEP 5. Check the harness for open circuit or short circuit to ground between combination meter connector C-02 terminal 51 and PCM connector C-91 terminal 80.
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Q: Is the harness wire in good condition?
YES: Go to Step 7.
NO: Repair or replace the harness wire.
- STEP 6. Check PCM connector C-91 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Q: Are the connector and terminals in good condition?
YES: Go to Step 7.
NO: Repair or replace the damaged components. Refer to How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .
- STEP 7. Using scan tool MB991502, check data list item 29: Vehicle Speed Sensor. CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
- Connect scan tool MB991502 to the data link connector.
- Start the engine.
- Set scan tool MB991502 to data-reading mode for item 29, Vehicle Speed Sensor.
- Check that the speedometer and scan tool display speed match when driving at a vehicle speed of 40 km/h (25 mph).
- 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 How to Use Troubleshooting/Inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .
NO: Replace the PCM.