Chrysler Repair: P1698 Error Code, powertrain control module, 1997 chrysler concorde

Question
I have a 1997 Chrysler Concorde LX.  The OBD II error code reads P1698, which means that the powertrain control module is not receiving data from the transmission control module.  The car is exhibiting the following symptoms:  when the key is in the 'on' position, the instrument cluster is functional and the fuel gauge reads the fuel level, however, as soon as the engine is started the instrument cluster is non-functioning, including the tachometer and speedometer.  In addition, the car does not want to drive at high speeds, it feels as if the transmission is not engaging in the highest gear.  How would I start to diagnose what the problem is?  What specific wires should I check for continuity?  Thank you.

Answer
First, this type of BUS diagnostic is somewhat difficult to do even under the best of circumstances. It requires that no other BUS failure DTC's are present and that the DTC you have is active. With that said, I'll need to get a bit more info first. From your description you indicate that there is a communication problem between the PCM and TCM. The communication network also involves the BCM, cluster and to some extent the ABS module as well as the wiring between them all. The first thing I need to know is wether or not the odometer displays a "no bus" message. If it does then you're looking at checking the PCI BUS wiring for a short to ground or power or and open circuit between any of the modules. If it does not display the message the next step would be to check for a P1695 DTC. If that is not present then you're back to checking the PCI wiring for shorts or opens. If it is present then you need to check voltage at pin 59 of the PCM connector. If no voltage is present then you need to check....

As you're stating to see, there is no clear cut or quick answer to your question. It will take a clear understanding of the BUS architecture, a good wiring schematic and a clearly defined diagnostic manual to locate the problem with your vehicle. I'll try to help you as best I can.