Technical Service Bulletin Recalls For Jeep Cherokee

Safety Recalls For Jeep Cherokee

Q: Need listing of the recalls (safety and other) for  1994 Jeep Grand Cherokee. Can you help me find this list? All I am able to find are some safety recalls and next to no Service Bulletins.

A: Any person can check on safety recalls by calling the National Highway Traffic Safety Administration at 888-327-4236 or at www.nhtsa.dot.gov. As for TSB’s (Technical Service Bulletins) that is a different story. First you have to understand that a TSB involves a problem. The first problem with a problem is its definition. In the Webster’s big book a problem is defined as 1. a question proposed for solution or consideration. 2. a question, matter situation, or person that is perplexing or difficult. 3. in mathematics (hey this doesn’t count here forget it, need the space) The problem is there is no #4. who pays to fix the problem? Is it the tech? No, he/she works for the dealership. After all you can’t feed a family or own a house if you don’t get paid. The dealership? Yea at first they’re stuck with the cost until they get the money out of the folks who designed and built the vehicle. Of course the first thing they say is there’s no problem- must be your techs. Once enough dealerships are screaming, (just like their customers) the maker realizes Oh, maybe there is a problem. In the interim the solution, or an in the field fix is found. Here’s where the cost of a TSB really jumps. The maker has to get this information out to all the other dealerships, to let their techs know how to fix the problem, which may include redesigned parts. Also if the car is new enough the repairs may be for free (eegkads!). Getting the TSB out to all the dealers and techs, not to mention any parts, costs big bucks. Loss of big bucks means loss of big bucks! There are research and development costs, warehousing, distribution costs, transportation & delivery costs, installation costs, not to mention the white shirts trying to justify their corporate existence, it just plain cost money! Then a person like you or me comes along and asks for this information for free? Right! Hey they got the investment and need a return. Even the folks at ALLDATA Information Systems  have to pay for the information and the right to reprint it. Whether it’s computers, medicine, law or cars information is not free. Someone (that is you or me) has to pay for information in its final form.

Vehicle Will Not Start After Replacing Transmission

 No Start After Transmission Replaced

No Starting Issues & Transmission Problems


Q: Dropped  transmission on Jeep Cherokee to replace the oil seals that were leaking badly. After put it back in and now it won't start. Do I have to re-calibrate the computer or something? Any help would be awesome.



A: If it cranks over good but will not run I’d be looking at the crankshaft position sensor. The crankshaft position sensor is mounted in the bell housing of the transmission. The sensor is mainly plastic with very, very small wires inside. If it is hit, the engine is a no go. The quickest test is with a scan tool. With the scan tool connected to the computer go the crankshaft signal screen and crank the engine over. The computer will say yes for a crankshaft signal and no if there is not one. If no signal, a replacement sensor is likely needed.

Engine Quits After Running Few minutes

Engine Dies After Driving Few Minutes

Q: The engine just quits on  Jeep Cherokee after driving for few  min. Already replaced the fuel filter, spark plugs & wires and the distributor cap....What else can I check?


A: First, you're not checking you're replacing parts. This is a costly way to approach a problem. If the problem is so persistent you should be able to time a drive to a repair facility for diagnosis. But then again if it is anything like what happens when a problem vehicle comes to our shop, the problem goes away. You know the dentist and the tooth ache scenario? It is unlikely that the parts or related parts to the items you've replaced are the cause for your engine just shutting down. With Jeeps I'm more inclined to inspect critical inputs to the computer. Component failures that I have seen that are heat related on Jeeps have been the crankshaft position sensor. When this sensor drops out (fails) the computer just stops doing about anything. The signal from this sensor is a critical input and without it the vehicle will not run. Why? The signal from the crankshaft position sensor allows the computer to know when to provide spark and fuel. The Jeep just becomes a boat anchor until the signal returns. A problem as persistent as you're describing should be easily diagnosed. Once you have the diagnosis and know what has to be replaced life gets simpler.

Vehicle Quits While Driving

Engine Goes Dead While driving

Q:  Jeep Cherokee runs well 99.9% of the time. However, sometimes when driving, it will go dead. Usually it cranks right up when I pull to the shoulder of the road. Sometimes it will run for days with no problems. Other times it goes dead two or three times a day. I had it in the shop for a week, but they could not find anything wrong with it. Any suggestions?

A: If your Jeep is shutting off like someone turned the key I would be critical of the crankshaft position sensor. While your Jeep is running you can unplug just about every computer sensor on the engine and it will still run, not great but run. If the signal from the crankshaft position sensor is lost on your Jeep, the curtain drops like a rock on that show. The fuel injectors, along with the ignition system, are shut right down. Just bang, end of show! While the crankshaft position sensor is off line from the rest of the vehicle, you can crank the engine over until the battery goes dead or the starter burns up, it's just not going to start. The next time this condition occurs on your Jeep, turn the ignition off and then cycle the ignition from off to on three times. On the third cycle leave the ignition in the on position. At this point watch the check engine light it should start to flash. If the code flashed is an 11 it is a good bet that the crankshaft position sensor has failed. So, the next time your Jeep drops dead, cycle the key and find out what the computer might have to share with you while you wait.

Air Conditioner Vacuum Doors Close with Acceleration

Jeep Cherokee, A/C Vacuum Doors Close with Acceleration

Q: Its 1988 Jeep Cherokee with a 4.0 engine. The problem is with the air conditioning doors changing position to vent upon acceleration. The engine and accessories feel good and are running great cruising down the road, except during acceleration. When the engine drops the vacuum level, the A/C unit controls lose vacuum supply and the doors shift to their neutral positions. When we reach cruising speed with traffic, the vacuum comes back in and pulls the doors to the intended position to get that good cold air back in your face. We've visually checked the main vacuum lines from the intake manifold port through the reservoir under the front bumper up to the firewall. Thought I would ask if this is a recognized problem before I bend over and go through the dash, emissions lines or 4X4 systems.

A: If the vacuum lines and vacuum reservoir are not damaged, you have a sticking or missing check valve in the vacuum supply to the vacuum reservoir. The vacuum reservoir is just what its name implies, a storage device for vacuum. The engine creates vacuum. The vacuum is an energy that is used as a power source to operate different emission controls and accessories like the controls for the ventilation system. There are times that an engine does not create a good supply of vacuum. Because of this the vehicle manufacturers install reservoirs to store vacuum. The hose from the engine or the reservoir itself will have a check valve that blocks the loss of vacuum back to the engine. Why is this? When accelerating, the amount of vacuum created by the engine drops to a level that will no longer power any emission controls or provide for control of the ventilation system. The reservoir is designed to hold enough vacuum in storage to maintain control under most driving conditions. If the check valve fails the vacuum reservoir will lose vacuum so quickly that there will be none left in reserve. The result? A loss of control of vacuum operated devices.

Violent Shaking Noticed on Jeep

Vehicle shakes violently while driving

Q: I just bought an ‘87 Jeep Cherokee from a guy I know and while driving it home it began to shake violently almost to the point of losing control. It will stop and restart again but does not seem to be at any particular speed. Any suggestions?

A: I would suggest inspecting the steering and front end components of the vehicle. There is one part in particular, called the steering stabilizer that should be checked over closely. The steering stabilizer is basically a shock absorber for the steering. This not to be confused with the shock absorbers for the suspension. The mass (steering and suspension) in the front end of Jeeps has a frequency problem, meaning that as the vehicle is being driven down the highway a sort of vibration develops. The steering stabilizer absorbs/deadens this vibration so it is not delectable. If the stabilizer is worn it can no longer prevent the front end shake from happening. The shake from a failed stabilizer can be speed related when the steering is turned slightly or when the wheels hit a small bump, just right. With a little time most people figure out just how to induce the shakes. Once the shake starts it will not end until you virtually stop the vehicle. Start driving again and the condition will return it will return at the right speed or bump in the road.

Jeep CJ-7, Water Problems

WATER MIXING WITH OIL ISSUES ON JEEP


Question: I've got an '84 CJ-7, 258 straight six. There is quite a bit of water-oil mixture in the valve cover. I've notice just a tiny bit on the dip stick. But, when I drop the oil there is no water. Also, there is lots of water-oil accumulation in the air cleaner. And I notice the radiator is short on water about every two months. I get the feeling I have either a cracked block or a blown head gasket but the engine is actually running under temp during normal operation.?

A:There's no need to get physical. I don't believe that you're cooling loss is related to the watery-oil problem in the valve cover and air cleaner. It's not uncommon for a vehicle of that age to have small leaks that could account for the loss. The accumulation of water-oil in the air cleaner is a good indicator that the Positive Crankcase Ventilation (PCV) system is not functioning properly. Next, you're going to ask, "Where did the water come from that's in the engine?"

Have you seen condensation on a glass of water? Well, the same thing happens to engines. With temperature change, moisture will condense and collect inside an engine. But, that's only a small part of the picture. The greatest source of water in an engine is the combustion process, the burning of gasoline. How do you get water from gasoline? Gasoline is a hydrocarbon (HC). When gasoline is mixed with oxygen and heat, a thermal-chemical reaction occurs, it burns. Am I scaring you yet?

As the gasoline (HC) and oxygen (O2) burn, they break apart and re-join becoming water (H2O) and carbon dioxide (CO2). Of course there are other chemicals but these two are the main players. The remains of combustion (exhaust) H2O, CO2 and other chemicals are supposed to exit the tail pipe, but that doesn't happen. A portion of the combustion gases leak by the pistons in the engine, into the crankcase.

The job of the PCV system is to pull these gases H2O, CO2, and other chemicals out of the crankcase so as not to contaminate the engine oil. If the PCV system is not operating properly H2O will collect in the valve cover and be forced into the air cleaner assembly. Cold weather will make matters worse.