tommygards

Hello all,

I am a new member and am hoping to become an active member of your site. I have a 2003 Grand Cherokee limited Auto. I will post up pics of my car this evening when I take some as a hello thread but in the mean time was hoping for some help in diagnosing a fault.

I have had the car a couple of weeks and now when I start the car in the morning or after it has been stood for a few hours the engine management light illuminates and the car goes into limp mode and wont change gear. however once the car is warmed up I can turn the car off and back on again and the light goes out and works fine and will continue to do so until it has been left standing for a few hours and cooled down again. I can't get the garage to read the fault code because it is several miles away and I only have 1st gear in limp mode, and by the time I get there the car has warmed up and when the engine is started again the light goes out.

Any suggestions? Thanks for your time, I will put up a hello thread this evening. Please dont think I only want help in diagnosing a problem and then will leave again because I won't.

Thanks

tommygards

I have just managed to get the codes from the off/on of the ignition and have codes P0620 and P0700. Which of these will more likely cause the intermittent problems I am having?

ol"blue

Welcome to CF. I checked your codes on wwjjeeps.com, and got the results shown below. The code 0700 looks like the most important one, and the cause of your issue. You need to take it to a dealer and drop it off, so they can have it first thing in the morning when it's cold. That way they can diagnose it when it's acting up as you claim. They may be able to fix your Transmission Control Module, or "reflash" it as they did to the one in my '04 twice when it was under warranty. They connect their computer to it and erase it, then reprogram it.

**The output speed sensor is a cheap part to replace if that proves to be the cause.

Good luck, and keep us informed.

P0620
Generator Control Circuit

P0700 (M)
Check Transmission DTC's
This code indicates that the EATX (Transmission controller) has an active fault and has illuminated the MIL via a BUS message. The specific fault must be acquired from the EATX via a DRBIII tool. (Input or Output Speed Sensor failures often cause this code and are a common failure part on WJ Grand Cherokees).

tommygards

thanks for all your help.

The only thing I find strange is that when the MIL does illuminate it is when I first start the car when I'm not moving, so I would find it surprising it is picking up a fault with the transmission unless it is a dodgy sensor.

I assume that code 0620 - generator control circuit, relates to the alternator??

I will get it dropped off to the local jeep, shame that they want £102 for just plugging it into the diagnostic machine

ol"blue

Yes I think that is the alternator.
I agree, but in some cases it must be done.

tommygards

hello again,

just as feedback for everyone what the issue was. The P700 fault was the transmission control unit was registering as excessive slip due to to not having a software update that it required. This has now been done by the dealership and has cleared the fault codes.

The P620 fault was due to a small hole in a fuel line that meant fuel drained out when the car when it was left for a while. When the car was then started it took a while for fuel to get to the engine and start the car. During this time the battery was getting drained by turning the engine over that brought up the fault of a low battery voltage.

dave1123

Bingo! Ol' Blue strikes again! Blue, don't ever go away. We need you.

ol"blue

Glad to hear the issue has been resolved.


You're a pistol Dave.