2002 Jeep Grand Cherokee



November, 6, 2013 AT 10:16 AM

Starting from the beginning. I replaced my engine about 2 weeks ago after it has been sitting for about 1.2 years. I have it up and running but I am getting a service engine light. I have received codes P1698, P0303, P0306, and I was told at one place that I had some P07? Codes(Tranny).

The vehicle also has shifting issues to go with it which did not occur before the engine swap. It will start in 3rd gear everytime. If it doesn't start in 3rd, it will jerk back into it while I am driving. It will sometimes jerk back and forth from where it should be back to 3rd gear.

I have replaced my TPS and TCM with no improvements. I have also checked all of my grounds. I need to know if a P1698 (no CCD data from TCM to PCM) is the cause of this and if so, which wire do I check to diagnose it. I have a multimeter and I am fine with schematics and diagrams but I have nothing to go off of.

Could it be another sensor? Speed sensor? I was told at aamco while they were going through a few diagnostics for free that it was coming up as going 20 mph while it was just parked. Could that be a PCM issue or is that just a sensor?

I don't want to replace anymore parts unless I have a legitimate reason to do so. Please help.


1 Answer



November, 6, 2013 AT 5:46 PM

You have a problem in the wiring between the TCM and the PCM or the TCM itself is bad. CCD is the data bus the computers talk to each other through. For some reason the TCM isn't sending required data to the PCM. As a result, the transmission doesn't know when or where to shift. What I recommend is that you check the wiring between the PCM and the TCM to see if there are any loose connections as well as damaged wires or solder joints. Check the wires for continuity. If they are all good, connections are good. Then I would recommend having the TCM checked or replaced.

PCM = Powertrain Control Module <> It's a computer that controls engine functions
TCM = Transmission Control Module <> A computer that controls transmission functions

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