When there is both P1694, and P1698, suspect a CPS issue. You can test/diagnose each code separately, but the most common cause for both to appear is a faulty CPS or CPS wire harness issues.
When the CPS short circuits, the engine computer (PCM) shuts down to prevent damage to itself. As a result, there is no communication (P1694).
Disconnect your crankshaft position sensor then put the ignition key in the on position. If the instrument cluster voltage and fuel gauges start to work once the CPS is disconnected, then you know the CPS or CPS wires are shorted and is the root cause of the codes. You can verify this by testing the CPS and checking continuity and voltage on the CPS wires.
http://www.naxja.org/forum/showthread.php?t=63167
http://wiki.answers.com/Q/What_does_code_p1694_mean_for_a_2000_Jeep_Cherokee
P1694 Fault In Companion Module. No CCD/J1850 bus messages received at the power train control module (PCM) from the AisinWarner Transmission Control Module (TCM).
P1694 will set if no CCd bus messages are received from PCM for 20 seconds or invalid messages are received for 20 seconds.
Possible Causes
-CCD Bus (-) circuit open between PCM and TCM.
-CCD Bus (+) circuit open between PCM and TCM.
-Transmission CCD bus wiring damaged.
-Faulty TCM
P1698 No CCD Messages Received From PCM. Bus communication failure to PCM. A "Companion DTC" was set in both the ECM and PCM.
Possible Causes:
- Faulty Engine control Module (ECM)
- Engine control Module(ECM) harness is open or shorted
- Engine control Module (ECM) circuit poor electrical connection
P1694 Diagnostic Procedure
1. Using scan tool, clear TCM DTCs. Start engine and let idle for at least 2 minutes. Using scan tool, retrieve TCM DTCs. If DTC P1694 returns, go to next step. If DTC P1694 does not return, go to step 5.
2. Check instrument cluster gauges for proper operation. If fuel gauge and speedometer operate properly, go to next step. If fuel gauge and speedometer do not operate properly, see appropriate INSTRUMENT PANELS article.
3. Turn ignition off. Disconnect Gray PCM harness connector. PCM is located at left front of engine compartment. Disconnect TCM harness connector. Measure resistance of CCD BUS (-) circuit (White/Black wire) between TCM harness connector and Gray PCM harness connector. If resistance is more than 5 ohms, repair open in CCd BUS (-) circuit (White/Black wire). If resistance is 5 ohms or less, go to next step.
4. Measure resistance of CCD BUS (+) circuit (Violet/Brown wire) between TCM harness connector and Gray PCM harness connector. If resistance is more than 5 ohms, repair open in CCd BUS (+) circuit (Violet/Brown wire). If resistance is 5 ohms or less, replace TCM.
5. Conditions necessary to set DTC P1694 are currently not present. Inspect related wiring and harness connectors. See WIRING DIAGRAMS. Repair as necessary. If no problem is found, check for broken, bent, backed-out or corroded terminal pins. Check for chafed, pierced or partially broken wires inside insulation. Repair as necessary.
