The description for fault code P1698 is "No CCD Messages Received From PCM" The CCD bus is the circuit that your computer system uses to communicate between the computers. There are several Computers in your vehicle. You didn't mention year or model or engine size, so I can't be specific, but most have at least an Powertrain Control Module (PCM) computer, Transmission Control Module (TCM) computer, an Antilock Brake System (ABS) computer, a Passive Restraint (Air Bag) computer and the Instrument Panel Cluster (IPC) when one of these computers are unable to communicate through the CCD Bus, the other computers will tell on it. Thus, code P1698.
This can be an internal fault in the PCM (not very likely) it can be a shorted or open CCD Bus circuit, or it could be caused by the PCM losing one of its power or ground circuits and momentarilly shutting down. If your instrument cluster is also having problems like you described, the problem is most likely a power or ground circuit malfunction. The rest of your computers need to be scanned to assist in pinpointing the actual cause of this code. The "Generic OBD" scanners that they use to sell parts with at the auto parts stores do not have the capability to scan your ABS, IPC, Air Bag, or other modules. They can also not access the "Vehicle Specific" side of your PCM. They can only scan the "Generic" codes that are output by the PCM. Again, this is most likely caused by an open or shorted circuit or even a malfunctioning ignition switch - something is most likely causing the PCM, the TCM or the IPC to lose power while you are driving.
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