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Discussion Starter #1
Hey guys -

My 7.3 Powerstroke had been rocking along without issue for a while and today my wife calls to say the truck has a check engine light. Ran AE and it came up with P1274, Cylinder #4 High to Low side open, P1298 Injector Driver Module failure. It won't complete CYL contribution tests, it says 'test failed'. I clear the codes and the P1298 comes right back.
Is this a legit IDM failure? Both the faults hang around after turning it off and back on. I did replaced UVC and glow plugs 2 years ago so they are 'newer'. Buzz test completes with #4 sounding muted - the rest sound pretty strong.

What would you recommend for the next steps in troubleshooting? I'm going to ohm out the injectors today. Part of me hopes it's a bad injector so I can upgrade them but how could I rule out the IDM? I do suspect it, it's a NAPA replacement because I turned in my factory good one because of another issue I had.

Thanks in advance!
Scott P
 

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Hey guys -

My 7.3 Powerstroke had been rocking along without issue for a while and today my wife calls to say the truck has a check engine light. Ran AE and it came up with P1274, Cylinder #4 High to Low side open, P1298 Injector Driver Module failure. It won't complete CYL contribution tests, it says 'test failed'. I clear the codes and the P1298 comes right back.
Is this a legit IDM failure? Both the faults hang around after turning it off and back on. I did replaced UVC and glow plugs 2 years ago so they are 'newer'. Buzz test completes with #4 sounding muted - the rest sound pretty strong.

What would you recommend for the next steps in troubleshooting? I'm going to ohm out the injectors today. Part of me hopes it's a bad injector so I can upgrade them but how could I rule out the IDM? I do suspect it, it's a NAPA replacement because I turned in my factory good one because of another issue I had.

Thanks in advance!
Scott P
little confused on parts used. Did you use napa brand UVCHs? if so those are the issue Napa reboxes Dorman brand and they are total junk and cause fires. Personally I love saving money but Napa, Advance Auto, Oriley, Autozone are almost always selling reboxed dorman products with their labels and causes all sorts of issues.

Have you tried pulling the IDM to check it out? It could have some water/corrosion a common issue with the 99-03 7.3ls because of pool sealing and location etc. I would replace anything from napa with Motorcraft asap personally.
 

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Discussion Starter #3
Hey Justin! No, all the parts (UVC and glow plugs) with the exception of the IDM are all motorcraft or international parts. I didn't have a choice with the IDM because I was in the road when I needed to replace it.
I also have an eBay IDM that I carry with me in case I needed it.
I haven't pulled the IDM out yet, and unless it was from a while ago I doubt water got in. It's been parked for a while and yesterday it was dry out. I'm still going to check it out eventually, of course.
I really think it's the IDM only because it's a reman and the code it's throwing. Just not sure if a failed injector actually throws an IDM code with it as a fake code. What do you think?
Thanks
Scott
 

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I see. Personally doubt its a failed injector its very uncommon for a 7.3l unless say you are 250k plus and it runs rough till warmed up. I would swap the idm and check the little wire pin connectors. I have to agree it sounds IDM related at this point and thanks for clarifying the parts used helps reduce odds of them being a culprit at this point at least. I believe a bad/failing IDM can cause false injector codes it was just way more common for the UVCH to have a loose/broken, not all the way clicked in clip or even needing shimmed on the injector (again not common and more of a band aid for high mileage units)
 

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Discussion Starter #5
Great thanks for the input on this. I will ohm things out then swap the IDM. Convenient to have a spare to try with.
What do you think of the Swamps high frequency/voltage IDM? I might spring for one from them, if that's what's at fault now I really don't trust the NAPA ones I have ...
Thanks!
Scott
 

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Discussion Starter #6
I'm at 203,000 and things have run well right up until this. Thinking that means injectors might be ok for a while. I want to do injectors eventually but I'm not in a hurry, my transmission is stock and still happy.
Scott
 

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Great thanks for the input on this. I will ohm things out then swap the IDM. Convenient to have a spare to try with.
What do you think of the Swamps high frequency/voltage IDM? I might spring for one from them, if that's what's at fault now I really don't trust the NAPA ones I have ...
Thanks!
Scott
not worth the money personally. good tune with the php hydra is a far better thing to spend the money on. Has way more customizable features for power/shifting too.
 

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Discussion Starter #8
Yeah quite honestly I've been wishing I could easily tweak my TS chip - emailed tunes would be cool!
I could probably get some loot for my TS once I converted.

So I'm troubleshooting now and can you believe my codes are gone? Buzz test on cold truck and all of them sound the same now. No more IDM code... Ugh. I love intermittent issues.

Scott P
 

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Yeah quite honestly I've been wishing I could easily tweak my TS chip - emailed tunes would be cool!
I could probably get some loot for my TS once I converted.

So I'm troubleshooting now and can you believe my codes are gone? Buzz test on cold truck and all of them sound the same now. No more IDM code... Ugh. I love intermittent issues.

Scott P
I'd bet on UVCH issues or a loose connection
 

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Discussion Starter #10
Just an update - I got under there and ohmed everything out that I could without removing the valve cover for now and it was all right at spec. Drove the truck a bit and no issue. Then I took it out yesterday and once again, SES light and a miss. Wow does it shake with a hole not firing!!!

Got home and it seems 'permanent' again. Doesn't clear - comes back right away each time. I hope it stays that way so I can actually troubleshoot. If I get a soft buzz on # 4 today with a cold engine, I'll ohm it out - if that is good then at least now I can change the IDM and see if it goes away to help isolate this issue.

Thanks again for the input - I'll keep you all posted.

Scott P
 

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Discussion Starter #11
Well, a full day of troubleshooting and I am still with issues. Pulled the inner fender, ohmed out the harness to the injectors, all reading 3.0-3.1 ohms. Cleaned everything, sprayed connectors with contact cleaner, used dielectric grease and reassembled. I even soldered in a small replacement part of the #4 injector wire where the insulation was barely worn through (i found this last year, it was all covered up with electrical tape and not damaged again) I start it up and bam - P1274 Cylinder #4 High to Low side open, P1298 Injector Driver Module failure codes come right back in after a few min of running. I hope they stay, then I'll see if I am getting a different ohm value from the #4 injector. If not... it HAS to be the IDM, right? I have a spare - I'm installing it after re-ohming. Now that i have done a lot more reading on it, it seems that when IDMs fail it's a bank at a time like you said - so I don't know what to think. I can only try it out.

Do the injector solenoids fail intermittently? I suppose the other thing to do would be to swap solenoids between #2 and 4 if it returns with the replacement IDM.

Thanks!

Scott P
 

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There are options for shimming the solenoid on injectors but more of a bandaid but worth a shot if you have it opened up already. At this point I would open up your spare and current idm and inspect and reseal and try the spare
 

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Discussion Starter #13
Well, it went as I hoped - I just hope it's fixed. 😂 still had codes, removed IDM - ohmed it out again - all good. Install spare IDM - runs great!! 👍
All I can do is drive it and see. Thanks again for the input - hope these posts help someone. I find so many posts about these codes and issues and it's rare to find 'this is what I did to fix it'

Scott
 
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