04 TJ No Start PCM?

[rikker001]

Won't be able to make it unless someone has a spare PCM laying around for an 04 tj automatic
or knows where to get one by Friday.

 

[junkpile]

What's the problem with it?

 

[rikker001]

The Jeep stated getting hard to start, gas gauge was screwy. Then Friday, I moved it about 30 ft turned it off loaded up some parts and tried to start it, it cranks fine but that’s it and only 2 volts to the fuel pump (pump comes on when 12 volts are put directly to it).

So of course went straight to Google, everything pointed the Crank sensor. It was broke so I changed it with a new one, tried to start it still cracks no start.

I then checked all the fuses and relays everything is good except no power to injector fuse. I also check that the gauges work by performing the speedo reset with key on, this is where is gets good.. There is a fault showing," B60,61 and 68 (Buss) Panel Open " and the Skim (security Key) is on steady.

This is why I think it is the PCM. Other than tearing the harness apart to find a bad wire, this I think other than cost is the easiest thing to do.

 

[smallville]

The Jeep stated getting hard to start, gas gauge was screwy. Then Friday, I moved it about 30 ft turned it off loaded up some parts and tried to start it, it cranks fine but that’s it and only 2 volts to the fuel pump (pump comes on when 12 volts are put directly to it).

So of course went straight to Google, everything pointed the Crank sensor. It was broke so I changed it with a new one, tried to start it still cracks no start.

I then checked all the fuses and relays everything is good except no power to injector fuse. I also check that the gauges work by performing the speedo reset with key on, this is where is gets good.. There is a fault showing," B60,61 and 68 (Buss) Panel Open " and the Skim (security Key) is on steady.

This is why I think it is the PCM. Other than tearing the harness apart to find a bad wire, this I think other than cost is the easiest thing to do.

u may need to do a crank relearn ?

 

[rikker001]

Whats that? Going to start a new thread.

 

[rikker001]

2004 LJ 4L, Auto

The Jeep stated getting hard to start, gas gauge was screwy. Then Friday, I moved it about 30 ft turned it off loaded up some parts and tried to start it, it cranks fine but that’s it and only 2 volts to the fuel pump (pump comes on when 12 volts are put directly to it).

So of course went straight to Google, everything pointed the Crank sensor. It was broke so I changed it with a new one, tried to start it still cracks no start.

I then checked all the fuses and relays everything is good except no power to injector fuse. I also check that the gauges work by performing the speedo reset with key on, this is where is gets good.. There is a fault showing," B60,61 and 68 (Buss) Panel Open " and the Skim (security Key) is on steady.

This is why I think it is the PCM. Other than tearing the harness apart to find a bad wire, this I think other than cost is the easiest thing to do.

 

[smallville]

i could swing by with modis and have a look

 

[junkpile]

Only if you don't mind throwing parts at it. Some or all of the codes could be related to one simple fix. If you're only getting 2v to the pump that sounds like you have some corrosion issues. I'd first trace the pump circuit. It may be as simple as a rotten wire.

 

[rikker001]

Checked all that out wiring is fine. Smallville came by last night, found that there is no communication to the computer.

 

[junkpile]

Still kinda sounds like a wiring issue. Actual PCM failure, although possible, is rare. Do you have a wiring diagram for the PCM? Make sure it's getting power and ground where it needs it. Then double check that the communication wires have continuity to the DLC.
Do you have an aftermarket remote starter or alarm system?

 

[Mlorint]

Google can be helpful but often misleading without proper diagnostic. From the information you've provided there is defiantly a corroded wire and broken one. It would be very common for the fuse box to have broken wires.


Sent from my iPhone using Tapatalk

 

[rikker001]

Not a broken wire but very close, Found a broked pin in one of the three connectors on the fire wall that was Intermittent. I bypassed the connector on that pin and it started no problem, still getting the bus issue on the cluster but at least its going under it own power going to see Smallville tomorrow and have it scan to see if he can figure it out. Thanks to everyone who had suggestions.

 

[dwcjwerfner]

Just a FYI for anybody else that might end up reading this thread. When I was reading it, I also agreed to myself that a bad PCM is rare. Well, the XJ which wouldn't start last year and then after plugging in a reader and not pulling any codes, I unplugged and plugged it back in with the power on it made a click and then started after. Earlier this spring I tried to start it again and no joy. This time when I plugged in the reader and it said that I was not connected. Hmmm, so today I finally pulled the spare off the shelf when it wouldn't start again. Fired right up, connected the old one, no go. Bolted the new one in and it works fine. I know this wasn't the problem here but thought I would just share of things to look for when diagnosing. It also helps to have a spare PCM on the shelf.

 

[rikker001]

Ah thats what I had also, no communcication to PCM, (red wire white tracer) so now I have a spare PCM. Really no big deal spares parts are always good to have.