engine code..... HELP!!!

[Swagger]

So, 04 Grand Cherokee, has been running pretty bad for about a week now.  I have ruled out bad gas (it's been through a tank and a half now), i replaced the spark plugs five days ago,  and just replaced the fuel injector today for cylinder #2.  each time i do something to it it runs beautifully for about ten miles, then the check engine light comes on and the engine starts spuddering like its missing on one or more cylinders.  i have had the trouble code read by a hand held code reader three separate times and each time it throws the same thing P0202: injector two circuit open/malfunction.   I am my witts end on this.  if the coil pack was messed up, both cylinders on that coil would be misfiring, right? i'm starting to think its a problem in the ECM? i hope not.  $339 bucks im not really wanting to spend right now.  Any advice?

[Bill3753]

Sounds like a good question for Bob.  I'd think ECM based what your saying now though.

[WillC]

P0202

Fuel injector circuit condition- Injector number 2
– The powertrain control module monitors the fuel injection electrical circuit for opens, shorts and system overload conditions.

Probable Cause

1. Open or shorted fuel injector's
2. Open or short in electrical circuit
3. High fuel pressure-pressure regulator defective-fuel return line blocked
4. Check TPS and circuit for failure

??

[Mr Rock]

I had a similar problem in my sons S-10 Blazer, it drove me nuts for about two weeks. it ended up being a shorted out o2 sensor that was nowhere near the injectors. The only relationship was that they shared a common wire. If I remember correctlly it was a 12v+ shared wire. In my experience it is never the ecm, they hardly ever fail.

[skibum]

x2 on what Will said except on the TPS sensor. Your problem is somewhere in #2 injector circuit. This code rules out the ignition system. First make shure that #2 injector has a good conection. Then make shure that there is no wire harness issue between the injectors & the PCM. A wire scamatic is good for this because you can do an Ohms test on the wires from injector #2 to the PCM to make shure there is a good conection. Sounds like you might have a bad PCM but you must be shure the wires have a good conection from the PCM to the injector. Swapping a PCM is not that simple on the 04 WJ because it needs the VIN# transfered for the antitheft security system. The SKIM module that reads the code in your Key needs to see the correct VIN# in the PCM to let the Engine start. The only way I no how to do this is with Dealer scan tools. Im shure there is aftermarket scan tools out there that will do this like SNAP ON, MAC, MATCO & some others but these scan tools are $3000 & up.  Hope this helps you.

[Swagger]

Took it to the dealer a couple of days ago. back probed and ohm tested the harness. final call- skunked PCM. F*** My life, i'm out 700 bones for this one and it's on back order from Chrysler until god knows when.  work schedule wouldn't let me get to it anyways.   But now there is a new variable.  I'm hearing a very loud, very prominent "hissing" noise (almost like the whatever it is that's wrong with it, is drawing a vacuum)  near my gas tank up a around the top where i believe the fuel pump goes in it.  Any ideas. i am almost done with this thing

[zjchef25]

hey i would just find a company who will flash over your current computer and give you better gas milage and some more power...