Chrysler Front Wheel Drive Cars 6-CYL 1988-1995 Repair Information

Vehicle Speed Sensor

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The 1988-90 and early 1991 Premier and Monaco vehicles use a combined crankshaft position sensor/vehicle speed sensor. Refer to the CPS procedures for this particular sensor in these vehicles. All other models use a vehicle speed sensor.

OPERATION



See Figures 1, 2 and 3

The vehicle speed sensor supplies the vehicle speed and distance inputs to the engine computer. The speed sensor is located in the transaxle extension housing to sense vehicle motion.



Click image to see an enlarged view

Fig. Fig. 1: Vehicle speed senor location on the transaxle-3.0L engines, except Premier and Monaco



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Fig. Fig. 2: The vehicle speed sensor on 4-speed automatic transaxles-3.3L and 3.8L engines



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Fig. Fig. 3: Vehicle speed sensor location-Premier and Monaco

The speed and distance signals, along with a closed throttle signal from the TPS, determine if a closed throttle deceleration or normal idle condition (vehicle stopped) exists. Under deceleration conditions, the PCM/SBEC adjusts the idle air control motor to maintain a desired MAP value. Under idle conditions, the PCM/SBEC adjusts the idle air control motor to maintain a desired engine speed.

TESTING



  1. Unplug the vehicle speed sensor wiring connector.
  2.  
  3. Turn the ignition ON .
  4.  
  5. Using a voltmeter, measure the voltage from the light green wire with the white tracer terminal of the wiring harness connector to a good ground. The power supplied to the sensor should be at least 4.0 volts; if it is not, then a problem lies with the circuit, the transaxle control module or the powertrain control module. These systems should be inspected before proceeding with this test.
  6.  
  7. Remove the distance sensor from the transaxle.
  8.  
  9. Connect an ohmmeter between the terminals of the sensor.
  10.  
  11. Rotate the sensor shaft while observing the ohmmeter. For each complete rotation there should be eight distinct pulses. Each pulse should not exceed 0.5 ohms.

    If sensor failed to perform as specified, replace the sensor and retest.
     
    If sensor was within specifications, check for a fault in the wiring, cable or drive mechanism.
     

  12.  

REMOVAL & INSTALLATION



Except Premier and Monaco

See Figures 1 and 2

When the vehicle speed sensor is removed for any reason, a new O-ring must be installed on its outside diameter.

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and support the front of the vehicle safely on jackstands.
  4.  
  5. Remove the speedometer cable (if so equipped) from the transaxle.
  6.  
  7. Unplug the harness connector from the sensor. Make sure that the weatherseal stays on the harness connector.
  8.  
  9. Remove the bolt securing the sensor in the extension housing or unscrew the sensor from the transaxle.
  10.  
  11. Place a pan under the sensor to catch any transaxle fluid which may leak out of the sensor mounting hole (not much, if any, will leak out unless the vehicle is now moved).
  12.  
  13. Carefully pull the sensor and pinion gear assembly out of the extension housing.
  14.  
  15. Remove the pinion gear from the sensor.
  16.  

To install:
  1. Clean the extension housing and sensor flange mounting surfaces. Install a new O-ring to the sensor.
  2.  
  3. Install the pinion gear back onto the sensor.
  4.  
  5. Carefully slide the sensor/pinion gear assembly back into the transaxle housing. Make certain that the pinion gear engages the gear inside of the transaxle correctly.
  6.  
  7. Install and tighten the retaining bolt, or sensor itself, to 60 inch lbs. (7 Nm).
  8.  
  9. Plug the sensor connector back into the wiring harness.
  10.  
  11. Install the speedometer cable and tighten the cable nut to 35 inch lbs. (4 Nm).
  12.  
  13. Lower the vehicle.
  14.  
  15. Connect the negative battery cable.
  16.  

Late Premier and Monaco

See Figures 3 and 4

If you are not sure whether your Premier or Monaco is designated as an early or late model, please refer to the model differentiation portion of this section.

When the vehicle speed sensor is removed for any reason, a new O-ring must be installed on its outside diameter.

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and support the front of the vehicle safely on jackstands.
  4.  
  5. Remove the under splash shield.
  6.  
  7. Remove the sensor cap bolt and washer.
  8.  
  9. Pull the sensor out of the transaxle.
  10.  
  11. Cut the tie strap securing the sensor harness.
  12.  
  13. Place a pan under the sensor to catch any transaxle fluid which may leak out of the sensor mounting hole (not much, if any, will leak out unless the vehicle is now moved).
  14.  
  15. Unplug the sensor connector from the engine wiring harness, then remove the sensor.
  16.  



Click image to see an enlarged view

Fig. Fig. 4: Installing a new O-ring to the vehicle speed sensor-late Premier and Monaco 3.0L engines

To install:
  1. Plug the new sensor's connector into the engine wiring harness.
  2.  
  3. Install a new O-ring onto the sensor.
  4.  
  5. Secure the new sensor's wiring with tie straps.
  6.  
  7. Slide the new sensor into the transaxle case.
  8.  
  9. Install and tighten the sensor bolt to 7 ft. lbs. (10 Nm). Make sure to install the washer as well.
  10.  
  11. Install the splash shield and lower the vehicle.
  12.  
  13. Connect the battery cable.
  14.