Check Engine Light Comes ON again n again

Jeep Cherokee Check Engine Light Will Not Reset

Q: Problem noticed on 1996 Grand Cherokee Lorado has 97K on it. I have taken care of the vehicle pretty well. Recently driving in upstate NY the check engine light came on. When I shut the it off and started it after a few minutes, the light remained on. I went on to remove the battery cable in order to reset the computer; this worked for a little while maybe 3 weeks. Within that time, I was getting very bad gas mileage, so I changed the O2 sensor. The one near the exhaust manifold was fouled and checking the one on the converter was ok . Also I’ve poured Textron additive because it was sluggish on initial take off from a stop. At times I’d lose power when I accelerated hard in overdrive. The light went on again, even when I reset it again by removing the battery cable it came on within the hour and the mileage is still bad. What do you think could be the cause of this problem, or do I need to go to the dealer for a diagnostic check up.


A: Yes you need to go to a dealer or and independent repair facility to get the answer to your vehicle’s problem. Also, whatever you do, "do not" unhook the battery before you go! Unhooking the battery causes the computer not only to reset, but in the process all information that the computer has to share, with the technician servicing your vehicle, is lost. An empty computer file will have no diagnostic information and you will get a bill for telling you there is nothing wrong. So, make the appointment, drive the vehicle and leave the battery alone. With the Check Engine Light on the computer will have the information you need to get your Jeep back to good running order.

Vehicle Goes Opposite direction at Sharp Turns

Turning Issues and Thumping Problem


Q: While engage the 4WD on 1996 Jeep Grand Cherokee, and turn to sharp corner, the front wheels sort of take me in the opposite direction and a thumping takes place...it is also really hard to steer. This only happens when I take a sharp turn doing 5 mph or when I turn at a green light, turning sharp while accelerating in the turn. Others have told me that they have the same problem with their Jeep. Is it true that Chrysler Corp had a recall for this problem in 1996?


A: Did you know that many 4x4 or All Wheel Drive (AWD) vehicles are not really 4x4/AWD? Many of these vehicles are either a front or rear wheel drive. It’s the technology designed into the drivetrain of these vehicles that allows them to transform, in merely a second, into a 4x4 or AWD vehicle, and you’ll never feel it happen, unless there is a problem with a device called a Viscous Coupler. A Viscous Coupler compares front wheel speed to rear wheel speed. If a difference is noted (rear or front wheels spinning) the Viscous Coupler engages and directs power to the wheels that are not spinning as well, making them all work together. If your vehicle is feeling jerky, and acting as if something is binding while turning sharp at low speeds, then the Viscous Coupler should be inspected. Diagnosis of the coupler takes a whole 5 minutes, but the repair will put a sizable dent in your checking account.

Vehicle Shudders while going Uphill

Jeep Grand Cherokee, shuddering

Q: Its the 1996 Jeep Grand Cherokee with 72K. All routine maintenance performed regularly without any missed. The vehicle is in great working order except for the following problem. Our check engine light keeps coming on when accelerating up hills at 55+mph. When we are about at the crest of a hill the light starts flashing then when the vehicle starts to down shift it starts shuddering real bad. This shuddering will last until you back off the gas and slow down. We have had the valve springs replaced, then had the mechanics do some work (because of the codes thrown) and this last week a new computer was installed. Two days after the computer was replaced the check engine light came back on under these same conditions. What could be the problem?

A: ALL DATA IS GREAT SOURCE. Join ALLDATA.The ALLDATA Information System shows several Technical Service Bulletins (TSB’s) that are related to driveability problems with check engine lights coming Here is the procedure explained for you to understand.
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The computer will report information to the technician that is not valid and send him/her down the wrong diagnostic path. With the recent replacement of the vehicle’s computer I would hope you got the latest and greatest software update. No, your Jeep isn’t running on Windows 98. If the computer is up to speed then the concerns move to the ignition and fuel system. If the problem is happening as the transmission down shifts and the engine RPM jumps higher than the norm, there may be a problem with the ignition wires. Strange as it may seem, we’ve found that under load and high engine RPM tired spark plug wires will introduce an immensely confusing engine skip that will not only turn the check engine light on, it also sends the computer into the high alert mode causing the check engine light to blink. The blinking check engine light on most ‘96 and up vehicles is the computer attempting to alert the driver to the pending doom of the catalytic converter. In closing, do not ignore the fuel system as a possible cause. A fuel pressure gauge should be installed and the vehicle driven in a manner that causes the engine to go into convulsions. Only then could you be sure of the abilities of the fuel pump. The fix will likely be simple. It’s finding the cause that will drive you nutz.

All Gauges Not Working

Troubleshooting Gauges Issues On Jeep

Jeep Cherokee, Gauge Problems 

Q: All gauges: The speedometer, tachometer, and gas gauge on 1996 Jeep Cherokee not working.Tried replacing the instrument cluster pod and still have the same problem. When they went out they would work off and on and the needles bounced around at times, then went out for good. Any suggestions?


A: Start with checking the fuses. The number 7 fuse in the fuse panel is a main player in powering up the instrument cluster in your Jeep. You should also realize that the action of the instrument cluster displays (speedometer, tachometer, gas gauge, etc.) are primarily a result of information processed by a computer called a Body Control Module (BCM). Because so many of your gauges are acting strangely the BCM is suspect. The BCM does have built in diagnostic abilities that can be accessed with a scan-tool. Virtually all of the lights and gauges on your dash can be operated via the scan-tool, through the BCM, for confirming function. Before replacing any more costly instrument clusters or installing a replacement BCM (the cost of a replacement BCM will create respiratory problems), be sure to check the fuses and electrical connectors. Proper diagnosis will save you money.

A/C blows on High Mode Only

Hi Speed A/C Blower Only For Jeep Cherokee

Q: Suddenly, Air condition will only work on the HI setting on my 1995 Jeep Grand Cherokee. If  set  to any other setting, no air will blow out. This sounds like an electrical problem but I’m not sure. Any ideas?

A: A very common problem.Your Jeep may be in need of a blower resistor. When you turn the blower speed control you’re directing electricity though different paths, all of which go to the blower motor. When you select low speed through mid speed you are really directing the electricity through a part called a resistor block. The resistor block has different resistors that control the amount of electricity that goes to the blower motor. But why only high speed? When the blower speed selected is high the resistor block is by-passed and full electrical power is directed straight to the blower motor. In most cases all that is needed is a new blower resistor block to return blower speed control.

Vehicle Stalls At Idle

Jeep Wrangler, Stalling Problems Troubleshooting

Q: Its a Jeep Wrangler 4.0L with an automatic transmission.

The Problem Noticed is :------ At cold start up it revs to fast idle then as it comes down to regular idle it stalls out. Restarting it may or may not stall again. When it reaches operating temperature, it runs fine.

Parts Replaced :----  The plugs, ignition wires, rotor and distributor cap were replaced at 2k-2.5k miles before stalling started and they still look good. Fuel pump pressure is normal. This vehicle has 143k mile on it and has given excellent service.

A: Take the air inlet hose off where it enters the throttle body and take a look at the throttle plates. It is likely that they’re dirty and have a build-up of carbon deposits. That is the most common cause for stalling that we see in the shop for your vehicle. Sometimes all it takes is a good cleaning to cure the stalling problem. There is an idle speed setting on your Jeep, but to check and/or perform this service step requires the use of a computer scan tool for your vehicle. If the cleaning doesn’t help ask a repair facility to check and reset, if needed, the minimum idle speed on your Jeep.

Ignition Coils Burning

Jeep Grand Cherokee Ignition Coil Burns Again n Again



Q: For Jeep Grand Cherokee. Idling very slow. I replaced the plugs wires and fuel filter but, still idled slow. I sent it to a mechanic who replaced the ignition coil and distributor pick up and it ran fine for one day. I took it to work and when I went to leave it wouldn’t start. I checked it and there was no spark so I took it back to the mechanic and he said the new coil went bad. He replaced it and it ran for 2 days then I went to drive it home from work and it wouldn’t start. I purchased another coil myself installed it and it fired right up. Do you have any idea why it’s burning up the coils?


A: Before replacing the coil too many more times you may want to go the Jeep dealer and buy an updated ignition coil and harness. The ignition coils were known for shorting internally, causing a variety of running problems. The update called for a lower internal resistance coil and a modification to the wiring harness that included an external resistor. If you’re installing an aftermarket coil that has a lower internal resistance without the wiring harness modification you’ll just keep burning out ignition coils.