Mopar 4707839AA Sensor-Vehicle Speed

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Remove the cable terminal from a negative terminal of the battery. If the model comes with a manual transaxle, then safely lift the car and put it on stands, then remove the wire harness from the VSS. Then, take out the VSS from the transaxle after which, the VSS drive gear can be withdrawn together with the old O-ring which has to be disposed off. I leave a new O-ring inside the housing of the VSS before I refit the drive gear as well as the VSS while using the retaining bolt. The process of installation is vice versa to removal process. If the car model has an automatic transaxle, there is the need to remove, in that order, the air filter housing, battery, battery tray and bracket. Remove the input shaft VSS electrical connector and then remove the input shaft VSS from the transaxle and throw the old O-ring before installing the new one then tighten the VSS. Second, disconnect the VSS electrical connector of the output shaft VSS, disconnect the VSS of transaxle, and throw the old O-ring away, and then insert a new O-ring and fasten down VSS tightly.

All models post 1988 have the OBD-II system enabling the owner to read engine codes, however early models need the ignition key while later models need a SCAN tool issued by the manufacturer. Should component checks fail in identifying a problem, a dealer or a qualified repair shop should attempt to determine the problem. After this test the OBD-II components, erase the PCM of trouble codes by removing the negative terminal of the battery for approximately ten minutes. Control of the PCM is accomplished with the compressor clutch engagement through a relay; this relay should have voltage when the A/C is on. It informs the PCM that there is an application of brake so as to sustain a certain level of engine speed. The camshaft position sensor codes cylinder information for purposes of fuel and ignition timing; the voltages must be specific: 0.1v for 4 cylinders and 0.3v for v6 cylinder. In the function of crankshaft position sensor, fuel injector sequence and ignition timing are significant, as for the similar voltage checks. The ECT sensor is the coolant temperature sensor; it should be tested at both cold and hot resistance. The IAC motor controls the idle speed and the IAT sensor measures the intake air temperature; it must undergo the resistance test at cold and hot conditions. With the knock sensor, engine knock is detected, and ignition timing is adjusted for it, with voltage checks required on both the old and the new models. MAP sensor is used to measure intake manifold pressure and delivers constant inputs used by the engine control module for fuel delivery and ignition timing; voltage testing is done on the supply as well as on the output signal. The oxygen sensors are used to monitor exhaust gases and are therefore dependent on some factors such as electricity and heat. These two switches include the PARK/NEUTRAL position switch and the power steering pressure switch since they impact the engine and must be scanned if they are faulty. The TPS watches the throttle position for change in the rate of fuel delivery and therefore must have voltage check while running. Located on the manual transaxles is the VSS which and gives out pulsing voltage to measure the speed of the vehicle; the system requires checks on supply voltage and output voltage for proper functioning. Every part replacement has its own protocol to guarantee correct affixation to the car part and proper working.

The Mark 20e Antilock Brake System (ABS) is designed to maintain the steerability of the car, the stability of its direction and the ability of the car to slow down on a particular road surface, to release or reduce the pressure on the brake line to avoid the lock-up of each wheel. It consists of three main components: the wheel speed sensors, the Hydraulic Control Unit or the HCU, and the Integrated Control Unit or the ICU; the latter receives input signals from four wheel speed sensors in order to detect near lock-up scenarios with tweaks hydraulic pressure by the use of solenoid valves. An 'ABS' warning light on the car's dashboard notifies the driver of system problems; these problems may be ascertained by inspecting the wiring harness for the ABS near each wheel for damages. Heating should be turned off before any of the electrical connections are loosened, and the ignition should not be on. If this warning light is on during operation, initial tests to check should include checking the brake fluid, make sure that electrical connectors are properly connected and properly inspect fuses and connects of wiring harnesses. However, if the above checks fail, one should seek help from professionals mainly because the system is complex. In order to have wheel speed sensor removal, the lug nuts must be loosened and the vehicle raised for the removal of the wheel. Check whether the ignition is off, find out the position of the sensor and remove the wires connected to the sensor and also remove the electrical connector, also take out the bolt holding the sensor and then, take out the sensor. Installation is done in the reverse sequence and always, there should be tightness on the mounting bolt and lug nuts before putting down the car.

To remove the camshaft reference sensor on 3.3L and 3.8L models, detach the sensor lead, loosen the bolt, and remove the sensor. If reusing, clean the sensor face and replace the spacer and O-ring. To install a new sensor, ensure it has a paper spacer and mount the O-ring. For the charge temperature sensor, unplug the connector, replace the sensor, and secure it with tape. For the coolant sensor, replace the cap, and the sensor, and check the coolant level. For the crankshaft sensor, unplug the connector, loosen the bolt, remove the sensor, and replace the spacer if reusing. For the TPS, check resistance readings, and replace if it is incorrect.

For models with a manual transaxle, unplug the VSS electrical connector, remove the retaining bolt, and take out the VSS. Then, remove the pinion driven gear and discard the old O-ring. Install a new O-ring coated with clean oil, then reinstall the drive gear and VSS, securing it with the retaining bolt tightened to the specified torque.