E-450 7.3 powerstroke PCM issues?

#1
Hey all, hoping someone might have some experience that can help me out here.

I have a 2001 E-450 (shuttle bus) with the 7.3l power stroke. I had check engine light on and bought the Kiwi 3 bluetooth dongle and used Forscan app to read the error codes. The codes (Code: P1316 - Injector Driver Module Codes Detected) and subsequent research led me to running a buzz test, the result of which was:
Code:
===  DTC  ===

P1272 - Cylinder #2 High To Low Side Fault

Diagnostic Trouble Code details

Injector circuit high to low side open

    - cylinder #2


--Possible Causes--

    - Open injector circuit.

    - Damaged injector.

    - Damaged IDM.

    - Damaged PCM.


Note: To clear this code, Clear Codes then Retest must be performed.



P1273 - Cylinder #3 High To Low Side Fault

Diagnostic Trouble Code details


Injector circuit high to low side open

    - cylinder #3


--Possible Causes--

    - Open injector circuit.

    - Damaged injector.

    - Damaged IDM.

    - Damaged PCM.


Note: To clear this code, Clear Codes then Retest must be performed.
After some additional research, it was apparent that some electrical issue was likely the culprit.

The next thing to try was just a simple checking of connection on the PCM... so I disconnected the batteries, then located and disconnected the PCM. A visual inspection revealed that while it seemed to be in fine shape (all pins looked ok), it did have a lot of dust and dirt all up in the connection area. So I blew it out with air.

I cleared the codes via Forscan, reconnected up the PCM, turned on the rig and what do you know, engine fires up and after a few minutes of idling the codes have note reappeared (like they had previously after just clearing them and restarting engine).

BUT.... now when I open up Forscan, it says "Powertrain Control Module: Unable to read DTC"

I can't seem to find any information if this is good, bad or otherwise... however, I thought/hoped to see "Successful DTC reading, no error codes found" like it says for OBDII & Antilock braking system (see screenshot below).

Other information that might be helpful:
  • vehicle starts w/ PCM attached
  • vehicle turns over but does not start with PCM detached
  • Forscan is showing error codes for Electronic Crash sensor (see below) but no dash/check-engine lights are on
If anyone has any thoughts I would appreciate it! Hoping I've missed something simple and I won't have to continue down the path of pulling off valve cover and checking injector wiring. Thanks in advance!

IMG_C9CFE9A04F20-1.jpeg
 
#2
I am skeptical of the injector harness as you have faults on both sides. I would start with checking fuses, wiring harness, and then IDM. The fact that messing with the pcm plug changed things has me thinking it’s a wiring thing. Check continuity of the wiring pigtail between the pcm and engine. You would know if the idm is faulty, runs rough and Smokey.
 
#3
"Powertrain Control Module: Unable to read DTC"

You may have blown the fuse that allows you to read codes.
I have owned close to 50 7.3 diesels and none have ever had a bad PCM or IDM.
Some have had them replaced due to bad troubleshooting.
UVCH is likely bad. It is a pain to change but parts are cheap at your local international dealer
Some of the CPS will throw the "injector side low errors" but they are usually 1 & 6
My local international dealer has the best parts at a good price and they will adjust prices in needed.

Time to get out the volt meter. This test will tell you where you need to focus your attention. It is also easy.

www.gbreman.com/techbulletin_103.html

if you are extremely strapped for money the "50 cent trick" will work but it is better to fix the harness. The valve cover is a pain to remove so do everything the first time..

Thanks
 
#4
I am skeptical of the injector harness as you have faults on both sides. I would start with checking fuses, wiring harness, and then IDM. The fact that messing with the pcm plug changed things has me thinking it’s a wiring thing. Check continuity of the wiring pigtail between the pcm and engine. You would know if the idm is faulty, runs rough and Smokey.
I've seen fuses mentioned in a few other threads as well so I'll definitely double check all those... engine fires up and seems to run fine.


"Powertrain Control Module: Unable to read DTC"

You may have blown the fuse that allows you to read codes.
I have owned close to 50 7.3 diesels and none have ever had a bad PCM or IDM.
Some have had them replaced due to bad troubleshooting.
UVCH is likely bad. It is a pain to change but parts are cheap at your local international dealer
Some of the CPS will throw the "injector side low errors" but they are usually 1 & 6
My local international dealer has the best parts at a good price and they will adjust prices in needed.

Time to get out the volt meter. This test will tell you where you need to focus your attention. It is also easy.

www.gbreman.com/techbulletin_103.html

if you are extremely strapped for money the "50 cent trick" will work but it is better to fix the harness. The valve cover is a pain to remove so do everything the first time..

Thanks
Thanks for that link! and the additional info. Any chance you can recommend how to get at the uvch? I can find info on the trucks all day long but finding van-specific info seems to be much harder to come by. Cheers!
 
#5
You have to remove the dog house inside.
I usually remove the alternator or AC compressor....but I leave everything connected to the AC and move it over.
Drivers side, Removing seat makes it easier.
I am assuming you don't have a passenger side front seat.
The worst bolt on each side can be removed from the tire well. It is easier if you remove the tire.

Run the test first that I posted the link to, it will tell you if you have electrical problems.
 
#6
You have to remove the dog house inside.
I usually remove the alternator or AC compressor....but I leave everything connected to the AC and move it over.
Drivers side, Removing seat makes it easier.
I am assuming you don't have a passenger side front seat.
The worst bolt on each side can be removed from the tire well. It is easier if you remove the tire.

Run the test first that I posted the link to, it will tell you if you have electrical problems.
so after running the test, most circuits tested at ~4 ohms EXCEPT 23 & 7 which came it at a whopping 147 ohms and 24 & 8 at about 5.5 ohms.

test 2 & 3 checked out fine.

I moved the coolant reservoir over to disconnect the IDM and behind it noticed some wires that look to have been rubbed pretty raw... *guessing* perhaps this could be the culprit but I'm not 100% sure where these wires are coming from or going to...
IMG_2983.JPG
 
#8
You can repair those wires. The voltmeter is saying that you likely need two UVCH, if those wires are inline they are likely causing the readings. All of your readings exceeded specs.

Inspect the wires extremely closely, if the copper is all intact you may be able to repair the wire insulation with some liquid electrical tape. There isn't much room or wire there to work with for splicing in new wire. Re-run the test after you make the repairs. If everything is under 2.7 ohms protect the wires moving forward and you should be good to go. (plastic wire wrap and electrical tape)

At least you have some real data and you can move away from the PCM and IDM.
 
#9
You can repair those wires. The voltmeter is saying that you likely need two UVCH, if those wires are inline they are likely causing the readings. All of your readings exceeded specs.

Inspect the wires extremely closely, if the copper is all intact you may be able to repair the wire insulation with some liquid electrical tape. There isn't much room or wire there to work with for splicing in new wire. Re-run the test after you make the repairs. If everything is under 2.7 ohms protect the wires moving forward and you should be good to go. (plastic wire wrap and electrical tape)

At least you have some real data and you can move away from the PCM and IDM.
Really appreciate all the help and advice. Thank you!


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#10
No problem.
I am not sure how far along you are with your build but you may want to consider a short school. They are a lot more rugged. The shuttle buses fall apart from abusive road use. I have both and the short buses are leaps and bounds better for getting off the pavement.
 
#11
My suggestion is to change those harnesses as soon as you can. If you pick the time and place to make the change it’s a lot better than waiting for them to fail.

Parts are relatively cheap and while they are a bit of a PITA to do there is no rocket science involved.

Also consider doing the fuel filter orings while you are under there.
 
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