HARNESS TESTING

2.4L Engines

NOTE: The 1993–95, 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 CPS harness connector 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 CPS terminal 3 and the ignition switch.
2. Turn the ignition switch OFF and check for continuity of the ground circuit, which is CPS harness terminal 2. If no continuity is found, repair or replace the harness from CPS terminal 2 to ground.
3. Turn the ignition switch back ON and check the voltage of the CPS harness terminal 4 (output circuit). The voltage should be between 4.8–5.2 volts, if it is not, repair the harness from CPS terminal 4 to ECM terminal 22.
4. If the harness passed all of the tests, it is good.
5. Plug all connectors back into their original components.

   Fig. 1: The numbering of the terminals on the component (sensor) side of the CPS connector — 2.4L engines

3.0L (12 Valve) Engines

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

   Fig. 2: The numbering of the terminals on the component (sensor) side of the CPS connector — 3.0L (12 valve) engines

3.0L (24 Valve) and 3.5L Engines

1. Unplug the MFI relay harness connector and the CPS harness connector. Insert the probes of the circuit tester into both ends of the harness. Check for continuity between the CPS harness terminal 3 and MFI relay terminal 3. If there is no continuity, repair the harness between these two terminals.
2. Plug the MFI relay connector back in. Check for continuity in the ground circuit, which is CPS terminal 1 to ground. If no continuity in the circuit, repair the harness between CPS harness terminal 1 to ground.
3. Unplug the ECM harness connector. Check the CPS harness terminal 2 and ECM terminal 68 for an open or short-circuit to ground. If there is a short or open-circuit, repair the harness between the two terminals.
4. Turn the ignition switch ON. Measure the applied voltage of CPS harness terminal 2 to ground. The voltage should be between 4.8–5.2 volts, if it is not, replace the ECM with a new unit. If the harness passed all of the tests, the harness is good.
5. Plug all connectors back into their original components.

   Fig. 3: The numbering of the terminals on the component (sensor) side of the CPS connector — 3.0L (24 valve) and 3.5L Engines