Checking Powertrain Control Module (PCM) Power & Ground Circuits (Cherokee)
- Turn ignition off. Disconnect PCM Black C1 connector. PCM is located in engine compartment on left front fender, near radiator support. Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, measure voltage between ground and terminal No. 22 (Dark Green/Black wire) at PCM C1 connector. See Fig 1
. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open fused B(+) circuit (Dark Green/Black wire) between fuse No. 22 (15-amp) in Power Distribution Center (PDC) and PCM. PDC is located in right side of engine compartment, next to battery. See WIRING DIAGRAMS article.
- Turn ignition on, with engine off. Measure voltage between ground and terminal No. 2 (Dark Blue/White wire) at PCM C1 connector. See Fig 1
. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open fused ignition switch output circuit (Dark Blue/White wire) between fuse No. 11 (20-amp) in fuse block and PCM. Fuse block is located behind glove box.
- Turn ignition off. Measure resistance between ground and terminal No. 31 (Black/Tan wire) at PCM C1 connector. If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, repair open in Black/Tan wire between PCM and ground. Ground location is located on right rear of cylinder block (2.5L) or right front of cylinder block, near generator (4.0L).
- Measure resistance between ground and terminal No. 32 (Black/Tan wire) at PCM C1 connector. If resistance is less than 5 ohms, ground circuit is okay. Test is complete. If resistance is more than 5 ohms, repair open in Black/Tan wire between PCM and splice S117. Splice S117 is located near take out in wiring harness for PCM. See WIRING DIAGRAMS article.
Courtesy of DAIMLERCHRYSLER CORPORATION