I recently finished installing a remanufactured 4.0 engine into my 1999 Jeep Cherokee XJ (AW4 automatic). The engine runs and starts, but we are having an electrical/gauge cluster communication issue.
The issue started after installing an upgraded gauge cluster from a higher-trim Jeep. On the first startup with the new cluster, everything worked normally for a couple minutes. Then several gauges suddenly stopped working:
Tachometer/RPM gauge stopped working
Speedometer stopped working
Oil pressure gauge appears not to be working
Temperature gauge is not working
Some other cluster functions still work
After this happened, the cluster displayed a “NO BUS” message.
A scan tool sometimes communicates with the Jeep, but communication seems intermittent. When it does communicate, it shows P1698 — No CCD/J1850 message from TCM (Transmission Control Module).
The transmission itself was recently serviced:
AW4 pan was dropped
Filter replaced
Pan cleaned and reinstalled
Refilled with ATF+4
No transmission flush was performed
The Jeep runs and drives, but the missing gauges and communication issue remain.
Things already checked:
Tried swapping back to the original gauge cluster — issue remained
Checked cluster connectors visually
Scanner can sometimes connect to PCM
Transmission fluid service did not change the problem
The problem seems like a CCD bus / communication / wiring issue rather than a transmission mechanical issue. Looking for advice on where to start diagnosing:
CCD bus wiring
PCM/TCM communication
Grounds
Cluster wiring/connectors
Possible harness damage from the engine swap
Any suggestions on common failure points on a 1999 XJ would be appreciated.