Jswfla

Bought a used, programmed (we provided VIN number to seller) ECM, and now the gauges don't work, and it dies after a couple SEC. We did installed a diagnostic tool that we bought at Walmart and gave us these codes:
P0443: Evaporative emission system purge control valve circuit
P0123: Throttle/Pedal position sensor/switch A circuit high
P0108: Manifold absolute pressure/barometric pressure circuit high
P0113: Intake air temperature sensor 1 circuit high.

Any ideas will be very much appreciated.

We have contact the seller, but another ideas wont hurt.

Thank you for your time

dave1123

If your battery wasn't fully charged or you used a jump pack to start it, you may have corrupted the programming. Ask me how I know that!

BlueRidgeMark

What is the back story? Why did you install a new ECM?

Jswfla

Vehicle was having trouble staring: the pump will kept priming unless we rotated de key in the ignition switch back and forward several time until the pump will stop, and the gauge will start working; then it will start. We went over everything for several weeks until we end up with the computer. The mechanic told my Dad the computer had 2 circuits burned, so we order one used in Ebay already programmed to our VIN. Computer arrive and it started right up, but it will die after a couple SEC and no gauges are working.

Noah911

What year is your Jeep? What year Jeep is the new used PCM from? Does your Jeep have security functions? If not, and the replacement PCM does? This probably means you need to get another PCM without SKIM. A SKIM equipped Jeep PCM needs to read the RFID chip from the original key. I think Jeeps which came with the grey colored keys are the SKIM Jeeps and the ones with the black keys are not? I could be wrong on the key color thing though, as I only know this applies to the Wranglers.

If your Jeep has security and so does the replacement PCM? This probably means you will need a dealer to program it for you via a DRBIII tool if it is an OBDII Jeep. (I cannot see nothing to know what Jeep you got because of my device)

dave1123

If you mean me, because it was covered in white aluminum "cheese" and was leaking silicone.

Jswfla

@Noah911 Jeep is a 1996. I have no idea from what year the PCM is. I will be nice to know if the computer came off a jeep with the SKIM. I asked the seller and her replies was "we dont know." We brought the jeep to a professional electrician since our head were ready to explode with some much confusion. I will post here what was the outcome. Thank you

Jswfla

OK... mechanic informed me that we need a key with the chip to be programmable. The one we have is not the original, nor has any chip in it. Spoke with a dodge dealership and I was told that the vehicle base on the last 8 digit of the VIN, does NOT have a key with the chip inside. WTF....

Noah911

If I understand you correctly? It sounds like you are saying that your 1996 Jeep per the VIN was not a SKIM equipped Jeep. It never did come with a chipped key then... And the replacement PCM per the mechanic is from out of a SKIM equipped Jeep. Does that sound right?

What you could do is figure out how to get a chipped key from online or a dealer. Go to the dealer and have them program this key to the new PCM. Instead of going through the trouble of changing out the ignition to match the new chipped key. All you would have to do is find a location to tape or secure the chipped key near to the steering wheel, and just leave it there permanently. That should work. And then you just start it normally with the key you currently have and the PCM will detect the chipped key which has been programmed to it.

Noah911

Or, exchange the new replacement PCM you have for another PCM which came out of a Jeep without having SKIM.

dave1123

WAIT!!! A 96 wouldn't have a SKIM so the alarm and immobilizer would be set with a key fob. With my 2000 XJ, a SKIM was optional. Grand Cherokees had them as standard equipment in 99 and up. The PCM you bought should have the same part number as your old one and the original programming should have been wiped and a new program for your VIN installed. This is why I hate dealing with Ebay. Bottom line, you should tow the whole rig to a dealer and have them straighten this out. Seriously, This is the only way to get it done quickly and properly.

94zj318

Usually if it starts for 5 seconds and dies, it has something to do with the Sentry-Key (SKIM) module. The SKIM comes in all 1999+ Grand Cherokees. I believe the SKIM has to be programmed to the ECM as well.

Cherryokee

" The mechanic told my Dad the computer had 2 circuits burned " This is important to note. Which circuits (wires, pins or signal_names) were burnt-up in the original PCM? The set of codes you currently are getting may point directly at those (possibly defective) circuits or sensors.

First: Identify the previously "burnt" signals/circuits and track them down, otherwise you may burn the new PCM in the exact same circuits as before.
Second: Replace the PCM with a 1996 compatible PCM - but only if you are satisfied that the cause(s) of burnt PCM circuits were found/corrected.
Third: Inspect and clean connectors/pins, clean any ground connection points that look rusted, inspect wires/harnesses for evidence of melted/cut wires and swap sensors around, wherever you can, to see if a trouble-code moves with the sensor in-question.
TIP: If you have access to the electrical diagrams and know how to use a multimeter then you will be able to troubleshoot by way of resistance and/or voltage measurements. Good Luck.

Noah911

I think you could probably do something like this and not have issues, for a 1996 Grand Cherokee?

It definitely would work for a 1999 model year and on up Grand Cherokee.. to get rid of SKIM, I would think?

dave1123

For a 99 and up Grand Cherokee, you can get a PCM programmed with your VIN, but leave the SKIM function dormant. Then remove or disconnect the SKIM module and the jeep will start, the PCM will search for the module, not find it, and set the key light, but continue to run. Then you can remove the bulb from the key light and run it forever that way, BUT the moment you reconnect the SKIM module, you'll have to use a chipped key. You should double-back the SKIM harness connector and wire tie it.

The 96 doesn't have a SKIM module or need a chipped key because the alarm and immobilizer function is controlled by the BCM (Body Control Module) and is set and disarmed with the key fob. You need a PCM that matches the part number of your original PCM and has to be reprogrammed with your VIN number. As I've already stated, this is most quickly done by a dealer with a DRBIII scan tool. This tool can scan the entire system and find the fault.

My wife's 96 Dodge Caravan did not have the SKIM feature and had a black plastic covered key that didn't have a chip in it. My 2000 WJ came with grey keys that are chipped. Any replacement keys for my WJ will be black and need a chip. The way the SKIM works is there is a ring antenna around the key switch and the module sends out an activation signal that turns on the chip in the key. The key gives out a coded number sequence that the SKIM module has to recognize as a valid key. The original keys have a "secret" code in them that only the SKIM module knows and can be used to activate additional replacement keys in a program that requires you to have BOTH original keys, otherwise a dealer must do it.

I know, clear as mud, right?