1996+ XJ has a CMP sensor inside the distributor housing. Failure causes intermittent no-start and P1391. Mopar 56026882; requires distributor pull.
On 1996-2001 XJ, the distributor no longer triggers spark - it spins the camshaft position sensor inside. Failure of this CMP sensor causes intermittent no-starts, stumbles, and P1391 (intermittent loss of CMP or CKP) codes. Replacement requires removing the distributor (or at least pulling its cap and rotor and reaching the sensor under). Mark the rotor position before removing the distributor so it goes back in the same orientation; if you spin the engine with the distributor out, you will need to re-time it. Mopar 56026882 is the OE sensor. Some owners replace this any time they have CPS replacement done because the symptoms overlap so heavily. Pre-1996 XJs do not have a separate CMP - the cam is timed indirectly through the distributor's HEI pickup.
| Part | Vendor | Est. price |
|---|---|---|
| CMP sensor | Mopar/RockAuto | ~$50 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.