2017 l5p: P0204, p0300

[chessy56]

I have a P0204 which seems to be fairly consistent, along with an occasional P0300. Looks like this is pointing to Injector #4. I haven't looked at the misfire PID (on my Edge CTS-2) yet, but I'd bet that it'll confirm what I am hearing/feeling. A little poking around on the web suggests that there may be a harness rub situation near the FICM to consider as well. Questions:
1. Exactly where is the FICM located? I read that a harness may be rubbing against something close by, possibly grounding out a line to the Injector.
2. Can I see this injector #4 from the wheel well without dropping the liner?
3. I've read previously that the pigtails used by the LBZ are a direct fit and a better option than the stock L5P pigtails. If so, does anyone have a part number?

After hearing of so many issues related to these pigtail harnesses from L5P owners, I'm betting initially that this may be my culprit rather than the injector itself. With 130K on her, it would appear that it's my turn in the barrel, so I'll try some contact cleaner to see if that buys me a few days of run time before being forced into a dealership for help. If I'm replacing one, I may as well buy and eventually replace all 8. Maybe I'll buy an injector as well. Looks like p/n 12698552 (advise if I'm mistaken).

Can anyone lend some advice on the location of the FICM, the LBZ pigtail part number and the access to the #4 injector harness?
Thanks!

[DmaxMaverick]

I don't recall the L5P has an FICM. I think they went with the wind after the LLY. The injectors are micro-piezo fired, and don't require a driver, in the traditional sense. Regarding the harness, and note I am not certain, the opposite bank harness should be the same. If you can, try swapping them to find out if the problem follows the harness, or stays with the cylinder/injector. L5P diagnostics is difficult, so far. Although there are a bunch of them around, they just don't seem to be having many specific problems. Most issues I've seen apply to most late model Diesels. Almost all issues I've seen are cured by removing or resetting power adding modules, restoring the (modified) PCM calibration, or involve the after-treatment systems.

[chessy56]

Thanks 'Maverick for the tips. Pigtail replacement connector ordered. I noted a couple of YouTube vids on replacing this connector (#7 on one, #4 on another). Looks like the wires are not polarity dependent. ACD #PT3739; GM #19368140 Little over $60 through Amazon. Noted an article that documented 3 common problems with the L5P, one being the #4 injector- but not so much the injector itself, but the connector. Same article stated a connector pigtail for an LBZ would be better, but aren't those injectors Bosch? Wouldn't a connector intended for a Bosch be different from the (Denso), or do they use the same connect interface? Curious to know as the same article referenced both the LB7 pigtails and the gold plated ones.

[DmaxMaverick]

I don't recall common issues with the LB7 harness, which are very different than later models. LB7 injectors are under the valve cover, and are connected with eyelets and nuts. The LLY #2 and #7 harnesses had chafing issues, which was addressed with a recall. I don't know if the L5P and LBZ connectors are compatible, either directly or with modification, but it wouldn't be a surprise if they were, either way. If one is more reliable than the other, and they are compatible, it's a no-brainer. I haven't seen enough of them, and haven't had a reason to follow this issue, so I'm just giving it my best guess.

[chessy56]

Repair pigtail installed on #4 injector. Put 75 miles on her- mostly highway- and no codes. Spliced/soldered the wires, a more reliable repair IMO. One thing I did notice was an oily residue on the inside of the hot pipe, post turbo. This might explain some of the oil I see collecting around the discharge port of the CAC. Question is, would this be considered normal or might I have an issue in the making?

[DmaxMaverick]

That sounds great. Hopefully that's a real fix. Did you take some pics?

Some oil in the CAC and plumbing is normal. The engine has a PCV that vents into the intake, so there will be some over time. You may even find a few oz. to drain if you pull a hose off the CAC. Residue is nothing to be concerned about. If you're seeing external oil around the lower CAC pipes, you may want to clean that up and tighten the clamps before they unclamp themselves.

[chessy56]

There is a couple of drops of oil around the exit port of the CAC and it's been my hunch that there is a poor connection of the return pipe at that joint- maybe enough to allow seepage but not enough to trigger a low pressure/air flow malf just prior to the TB valve (which has been identified as a potential cause for the P026D DTC). That's a connection I've yet to look into; I've been seeing a few drops of oil at that point for quite some time now.

Sorry, no pics of the fix with the connector/pigtail. I based my repair on youtube videoes done on a couple of L5P injectors and/or connectors. The guy seems to be a DIYer who has videoed about 3 different times he's done an injector issue on the L5P, on either side, capturing the event step by step. Interesting stuff even if the specs on bolt tightening are missing. Here's one of them: https://www.youtube.com/watch?v=QxLAK0wQp8s. The dude also covers how to change the cal data when the injector is replaced on a L5P that hasn't undergone "weight loss". He uses an Autel MaxiCheck MX808 BT (different video, same guy: https://www.youtube.com/watch?v=7RqGA3lXGyI). He also shows how he got the EGR pipe out to get to the #3 injector too.

If you view the one he did on the #7 injector you'll see exactly what I did- only he used the crimp butt slices whereas I soldered mine. Given the propensity of these OEM connectors eventually failing, I'm certain I'll revisit this task again, at which time I'll snap some pics and post them. Beats shelling out $$ to the local dealership even if it does take me longer! Thanks again!

[DmaxMaverick]

Thanks for the info.

I recommend moving the CAC connection up the priority list a bit. If it's leaking externally, it's leaking through the connection. The oil can penetrate the connection, allowing it to blow off under pressure. A lot of bad things can happen during that short period before the computer cuts the fuel. Turbo overspeed is one, but enough to kill a turbo.

[chessy56]

Thanks for the info.

I recommend moving the CAC connection up the priority list a bit. If it's leaking externally, it's leaking through the connection. The oil can penetrate the connection, allowing it to blow off under pressure. A lot of bad things can happen during that short period before the computer cuts the fuel. Turbo overspeed is one, but enough to kill a turbo.

Sorry for the late reply. Looking for the O-ring seals for that CAC connection. Doesn't look like too bad of a job- just like everything else that requires removal of a few things to make access easier. Thought there might be a kit (2 O-rings and a spring clip) but not finding it. Agreed- it needs to be addressed, although it's been slowly leaking for 5 years now with 130K on her. If anyone viewing this knows of an O-ring kit available, I'd appreciate a p/n if one's available. And, wondering how much of a PITA installing the cold air pipe to the CAC will be....
Thanks All-