Five problems related to emission control have been reported for the 1999 Jeep Grand Cherokee. The most recently reported issues are listed below.
The vehicle exhibits a sag/hesitation following a partial cool down restart, possibly an oxygen sensor problem. While making hard left turns at slow speeds (such as a u-turn), the airbag warning light illuminates and a audible chime is activated. The right side brake light assembly is burnt (internally) due to some kind of electrical overheating. The vehicle shifts hard, misses shifts, shifts repeatedly at constant speed and on a level grade. The rear differantial "bumps" very hard within 3-20 seconds of coming to a complete stop. An immovable "fog" has developed on the lenses of the composite headlight assemblies.
Crank sensor failed. Yh.
Gas tank was replaced mid July of 1999. After that date, the "check engine" light appeared. Service department claimed that the oxygen sensor was bad and replacing the part would fix the problem. The following day, the "check engine" light appeared again. Dealership was notified, but the service department was too busy to service us in the next few days. We went down to orlando FL, where we purchased the vehicle, and they saw the car immediately. The service department's diagnosis was the same as the dealership in jacksonville, FL. Oxygen sensor was reported as bad and replaced a second time in less than a week's period. The following day, on the way back to jacksonville from orlando, the "check engine" light appeared again and the dealership was notified in jacksonville. We are scheduled to have the car service again to correct the problem. Furthermore, the car is now running rough; indicating that the light is not just a malfunction, put a potentionally serious problem.
O2 sensors failed. Nlm.
Engine repaired eight times due to fuel pump, spark plug and oxygen sensor failures. Yh.