Chrysler RAM50/D50/Arrow 1979-1993 Repair Guide

Crankshaft Position Sensor

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OPERATION



See Figures 1, 2 and 3

On the 2.4L and 3.0L engines, the Crankshaft Position Sensor (CSPS) is located inside of the distributor with the CPS.

The CSPS detects the crankshaft angle, therefore the position, of each cylinder, and converts this data into electrical pulses. These pulses are created by the CSPS by intermitting the flow of current applied from the ECM. The ECM analyzes the pulses and can use this information to know when and how to control the fuel injection timing and ignition timing.

If an impact is suddenly felt during driving or the engine suddenly stalls during idling, try shaking the CSPS during idling. If the engine stalls, the cause may be presumed to be improper or incomplete contact of the CSPS's connector.

If the CSPS output rpm is 0 rpm during cranking (when the engine cannot be started), the cause may be a malfunction of the CSPS or a broken timing belt.

If the indicated value of the CSPS output is 0 rpm during cranking (the engine will not start), the ignition coil's primary current may be malfunctioning to intermittently pulse correctly, so a malfunction of the ignition system circuitry, the ignition coil and/or the ignition power transistor is probably the cause.

If idling is possible even though the CSPS indicated rpm is a deviation from the standard value, the cause is usually a malfunction of something other than the CSPS. It could be a malfunction of the ECT sensor, the ISCM, or an improper adjustment of the standard idling speed.



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Fig. Fig. 1: The CPS, along with the crankshaft position sensor, is located inside of the distributor-2.4L engines



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Fig. Fig. 2: The CPS and CSPS harness connector is mounted on the firewall on Pick-up trucks equipped with the 2.4L engine



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Fig. Fig. 3: On 3.0L engines, the CPS and CSPS are located inside of the distributor

HARNESS TESTING



2.4L Engines

See Figure 4

The 1993, rear-wheel drive 2.4L (California) Pick-ups have the same engine controls as the 3.0L engines. All other 2.4L engines are listed as 2.4L engines.

  1. Disconnect the CSPS harness connector (the same as the CPS) and turn the ignition ON. Measure the power supply voltage of CPS harness terminal 3 (to ground). The voltage should be the battery voltage (i.e. 10-12 volts). If this is not the case, repair or replace the harness between CSPS terminal 3 and the ignition switch.
  2.  
  3. Turn the ignition switch OFF and check for continuity of the ground circuit, which is CSPS harness terminal 2. If no continuity is found, repair or replace the harness from CSPS terminal 2 to ground.
  4.  
  5. Turn the ignition switch back ON and check the voltage of the CSPS harness terminal 4 (output circuit). The voltage should be between 4.8-5.2 volts, if it is not, repair the harness from CSPS terminal 1 to ECM terminal 21.
  6.  
  7. If the harness passed all of the tests, it is good.
  8.  
  9. Plug all connectors back into their original components.
  10.  



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Fig. Fig. 4: The numbering of the terminals on the component (sensor) side of the CPS connector-2.4L engines

3.0L Engine See Figure 5

  1. Unplug the MFI relay harness connector and the distributor harness connector. While touching the ohmmeter probes to both ends of the harness, check for continuity between the CSPS (CPS/distributor) harness terminal 3 and the MFI relay harness terminal 5. If no continuity is found, repair the harness between these two terminals.
  2.  
  3. Plug the MFI relay harness back in, and check for continuity in the ground circuit, that is terminal 4 of the CSPS (distributor) harness to ground. If no continuity exists, repair the harness between CSPS harness terminal 4 and the ground.
  4.  
  5. Unplug the ECM harness connector. Check for an open or short-circuit between the CSPS harness terminal 1 and ECM harness terminal 22, and CSPS harness terminal 2 and ECM harness terminal 21. If a short or open-circuit is found, repair the harness between the two terminals.
  6.  
  7. Turn the ignition switch ON. Check the output circuit voltage. This is the CSPS harness terminal 2 to ground. If the output voltage is not 4.8-5.2V, replace the ECM with a new unit.
  8.  
  9. Plug all connectors back into their original components.
  10.  



Click image to see an enlarged view

Fig. Fig. 5: The numbering of the terminals on the component (sensor) side of the CPS connector-3.0L engines

COMPONENT TESTING



Dodge does not give testing procedures of the CSPS itself with an ohmmeter. To test this component an oscilloscope is needed. Due to the high cost, and special skills needed to operate the tool, have the system diagnosed by a dealer or reputable service facility.

REMOVAL & INSTALLATION



On the 2.4L and 3.0L engines, the CPS is located inside the distributor. If the CPS is found to be faulty the entire distributor must be removed and either rebuilt or replaced. Refer to Engine And Engine Overhaul for distributor removal and installation procedures.

 
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