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This page will list all the Check Engine Light questions and answers asked of us pertaining to Jeep vehicles. Some models include the Liberty, Grand Cherokee, Wrangler, Compass, and Patriot.


2006 Jeep Liberty CRDQuestion: 2006 Jeep Liberty CRD auto trans I recently had to have my car boosted when it would not start in cold weather. After this my engine light has been on with no apparent problems in vehicle operation. The OBDII code is P0610 but would not reset? Your comments would be appreciated Thanks in advance - Gord, January 2009

Answer: Hi Gord. A P0610 code is Control Module Vehicle Options Error. I have not come across that code personally so I did a little digging on that code. It appears it pertains to the PCM (powertrain control module). That's basically the computer that is the "brain" for your Jeep, it controls a lot. I found two articles that are helpful and both pertain to the P0610 code - One Two. It sounds like the PCM will have to be reflashed or replaced. Your best bet is to get it into the dealer for proper diagnosis, they may have additional troubleshooting steps to follow. Good luck!


2001 Jeep CherokeeQuestion: 2001 Jeep Cherokee - 97500, 4.0L S6, replaced air filter and serpentine belt. Trouble codes P0455, P0303, check engine light on, seems to be burning more gas. - Ron, September 2008

Answer: Hi Ron. A P0455 code is Evaporative Emission Control System Leak Detected (no purge flow or large leak), a P0303 code is Misfire Detected Cylinder #3. P0455 is an emmissions-related code and the P0303 is categorized as an ignition/misfire code. I found great articles here - [P0455] [P0303]. Basically the P0455 means you have a leak in the EVAP system. Possible causes could include a faulty gas cap (or inferior replacement cap), a vacuum hose broken / worn, etc. The ideal method to diagnose is using a special smoke testing machine. Without that you could visually check all EVAP hoses from under the hood to the gas tank and inbetween. Then replace the gas cap with a new Mopar/Jeep one. As for the misfire, it could be a few things. If the spark plugs & wires are original, start by replacing those. A P0303 could be caused by a bad spark plug or wire, bad ignition coil, bad fuel injector, etc. The link I put in there earlier gives more causes. Good luck!


2003 Jeep Wrangler Check Engine LightQuestion: 2003 / Jeep Wrangler / 4.0L engine / manual transmission / 42000 miles / P0204 MIL on and was flasking at first, engine runs rough and would cutback at 3K RPMS. On advice, changed gas cap. pulled battery for approx 30 min. After that, MIL stays on steady (no more flashing). Engine still runs rough, but DOES NOT cutback at 3K RPMs anymore. Took it to Autozone and had them check OBD code. It read P0204. Had them clear the code and restarted vehicle. Initially, no MIL light. After 1-2 minutes, MIL came back on steady. Checked code again... P0204 again. Could this be caused by TPS module? Matt - September 2008

Answer: Hi Matt. A P0204 code is Injector Circuit Malfunction Cylinder 4. Who advised you to change the gas cap? That's advice for emission related codes, not injector codes. The TPS (throttle position sensor) won't fix this either. This P0204 code refers the the fuel injector circuit (circuit meaning the electrical wiring). Take a look at the wiring and connectors leading to/from the fuel injector for cylinder #4. Make sure it's connected. Inspect for broken or frayes wires. It sounds to me like your problem lies in the wiring to that injector. Good luck!


2005 Jeep Grand Cherokee Check Engine LightQuestion: Hello, 2005 6cyl jeep grand cherokee. 15,800 miles. check engine light stayed lit-up when i started car. next morning was normal. 5 days later,stayed lit-up again. jeep was 4 weeks past orig.3yr warranty period. took to dealer and they ran diagnostic test. fault code was u0404. said i needed to replace shifter/electronic control module. since it was past warranty, it would cost me $657.00. i said i'd let them know. called jeep to find out if they would help on cost to replace. jeep talked to service manager at dealer and manager told me they would replace for $190.00 as per jeep. offer is good for 30 days. engine light has not stayed on since i told dealer i'd let them know which is now 22 days. should i believe i neeed to replace module and accept offer? thanks - Ron, September 2008

Answer: Hi Ron. The description for a U0404 code is Invalid Data Received From Gear Shift Control Module. Since a Jeep factory-trained technician has looked at your specific problem, given you the code and diagnosis, I'd say, YES, definitely take them up on the offer and get it fixed. The reality is if you don't fix it now it may wind up costing you the full $657 a year from now. Do you see what I'm saying? I guess the other option would be to take it to a different shop and get a second opinion. But honestly since they've already looked at it and are willing to give you a discount on the repair, I say let them do it! Thanks for the question.


2004 Jeep LibertyQuestion: 2004 Jeep Liberty ,mileage-65000. trouble code - p0073 , p0073pd. - Oklo, August 2008

Answer: Hi Oklo. There's not much info there in your question but I'll help with what I can. The P0073 OBD-II trouble code is described as Ambient Air Temperature Sensor Circuit High Input. That refers to the circuit of the outside air temperature sensor. The sensor will be mounted in front of the radiator, behind the grille. Likely the problem is that the sensor has failed, or the wiring has a short in it or it's frayed. Inspect the wiring & connectors leading to the sensor. You can also refer to a Jeep Liberty repair manual for specific information, but you can also use a DVOM (digital volt ohm meter) to verify the Ohms of the sensor. If in doubt as to your ability to perform the above, please contact a trusted, qualified technician. Thanks for your question.