Having problems with your Jeep Grand Cherokee ?
ASD relay dosen't get ground signal from PCM. ASD relay has B+ and ignition +, ground wire from ASD socket to PCM is OK. When ASD circuit is jumped, PCM still has no 5v reference or communication to data link. PCM has ASD output acknowledgment when ASD is jumped. PCM has fused B+ and ignition + and both grounds. All diagnostics pointed to bad PCM. Got a used PCM and had it properly programmed right down to the VIN and mileage. Same results. I'm running out of options.
You say two wires have power and the other two would go (one is ground from computer the other to the fuel pump ect after the relay is grounded.When you jumped the relay did the jeep start or have fuel pressure .The no voltage to the obd2 connecter does not get it from the asd relay i am sure you checked all the fuses and fuse lnks correct.Worse comes to worse run a ground wire from the ground point on the asd relay wire that goes to the ecm. the relay still will not be activated with out the key on BUT please recheck all the fuse links..
Ignition switch or major wiring issue get schematic and trace out!!!!
Repair Help & Product Troubleshooting for Jeep Grand Cherokee
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