LBZ: Thought I had it figured out... P2123

[Cornell]

My RCLB LBZ threw this code last week and blew the dipstick out of the tube at the same time. I attributed the dipstick to the -10* weather and my PCV reroute freezing up. I checked the wiring harness from the gas pedal for any shorts or anything goofy. Didn't find anything so I replaced the pedal. Truck was fine for 2 days and then today it threw the code again on my way to work. Should I check the wiring again? Sure seems like a wiring issue to me but it quit after I replaced the pedal this weekend and drove fine. Also any reason it would be doing it because of the cold?

It's been 0 to -15 here for the past week with windchills down to -35

 

[c20elephant]

Subscribed, did the freeze and ruin the parts in the PCV at the valve covers? Something not working to relieve the block pressure that a PCV would normally take of.

Not that it freezes where I live but up in Northern Arizona where I visit on occasion it does. My PCV was re-routed to a 8x6x2 box/can bolted below the passenger door on the frame rail.

 

[Hot COCOAL]

http://www.duramaxdiesels.com/forum/showthread.php?t=45926
Here's a link to a similar issue that you joined in on, all signs indicate a wire at the throttle pedal rheostat, as I read you've already addressed, but there may be chaffing on that wire somewhere, you were in this thread and stated you had it fixed, so was that not the issue then?

That being said, do you really think that the pcv being blocked would result in the dipstick getting blown out? Furthermore, how would there be enough moisture to completely block off the pcv due to freezing, the pcv tube is 5/8" ID isn't it?

I would be worried that there is a coincidental issue that occurred with the wire thing that is much more severe...

 

[Cornell]

Subscribed, did the freeze and ruin the parts in the PCV at the valve covers? Something not working to relieve the block pressure that a PCV would normally take of.

Not that it freezes where I live but up in Northern Arizona where I visit on occasion it does. My PCV was re-routed to a 8x6x2 box/can bolted below the passenger door on the frame rail.

Nothing seems like it was ruined. I washed the truck and sprayed the underside off in a heated shop to get the salt off then pulled it outside and I'm guessing it froze then. My reroute comes down past the drivers side fender liner and is zip tied by the frame rail, cut at a pretty good angle. But the hoses were a bit long and ran parallel with the ground.

http://www.duramaxdiesels.com/forum/showthread.php?t=45926
Here's a link to a similar issue that you joined in on, all signs indicate a wire at the throttle pedal rheostat, as I read you've already addressed, but there may be chaffing on that wire somewhere, you were in this thread and stated you had it fixed, so was that not the issue then?

That being said, do you really think that the pcv being blocked would result in the dipstick getting blown out? Furthermore, how would there be enough moisture to completely block off the pcv due to freezing, the pcv tube is 5/8" ID isn't it?

I would be worried that there is a coincidental issue that occurred with the wire thing that is much more severe...

Yeah I joined in and figured it was just a bad throttle position sensor after I looked at the harness and followed it for a bit...I replaced the pedal and it went away for 2 days like I said in the OP. This morning it was really cold and a windchill near -30. The pcv tube is 5/8" ID.

Also the dipstick wasn't blown out like there was immense pressure in it. Just was loose enough that it blew oil by. I changed the oil the same day and it could have been that I didn't push it all the way back in either.


What I did this time around:

I took my Race tune and dialed it back a good bit, swapped my CAI for the stocker and made sure the PCV tubes didn't have any kinks in them (which the drivers side was slightly) When the code was thrown the turbo would surge really bad almost like it had a huge boost leak. I checked the balance rates and nothing even came close to standing out. Truck runs great when it doesn't throw the code, engine is nice and smooth.

Since I just changed the oil would it benefit me to run it a couple hundred miles and have an analysis done? Since I've done that stuff today I've had it idling and ran it for a good hour and no code yet.

Also this weekend I made my own winter front since a 2500HD winter front won't fit anymore because I deleted the plastic spacer piece when I raised my bumper so now my engine temps are getting up to where they should be.

The dipstick hasn't come out again either. If it did I would be worried that I cracked or holed a piston but that doesn't seem to be the case yet. But if I did its time for some twins and a nice little build. :roflmao:

edit: To me it seems like a wire grounding or chaffing issue, but I didn't find anything. Coincidentally I'm ripping the entire interior out next week anyways to replace it with an SLT interior. I guess I can follow it a bit better then if I can't get it figured out now. I had an issue with my drivers side brake light not working this spring and I chased the harness a good 3' into the loom and found a broken wire so I can't rule it out.

edit 2: also today my blower motor only works in position 5. Whoever owned the truck before me has wires all cut up under the passenger footwell. It's the same genius that had a relay wired on his aftermarket radio that sent power to ground and made the dash cluster gauges work intermittently when the relay would turn off and on.

 

[Hot COCOAL]

Well gawd dam son, you'd never know your truck had ANY issues by lookin at it, I've always liked your truck, it's ridiculous. Glad to hear about the dipstick, at first read I was like, oh snap that can't be good, but further explanation made more sense, my PVC hose pinches a bit on the drivers side too :hug: I need to fab up my own makeshift air dam, it's been Down to 10*F and my heater doesn't blow to hot, my trans stays cold and my engine doesn't get to full operating temp for and hour, 15min warm up and 45 of mixed driving...negative side affects of the egr delete and heater grid delete I suppose.

Electrical gremlins are a bear and can happen anytime and anywhere, like the one you found 3' into the loom, I chased one in my buddy's suburban for like three days, turns out his wife climbed the console and pivoted on her heel in the same spot, for years, and that action damaged wires in the loom in the middle of the cabin more or less....PITA to figure that one out

KUDOS once again to you for the due diligence to figure out yet another electrical related issue....you must have a heated shop...

 

[02greysixer]

I battled a similar issue on a 6.0 Powerstroke at work. Come to find out Ford used a common 5v reference wire to feed the ebp, egr, icp, and app sensor. The ebp got filled with coolant and shorted out wreaking havoc on the engine control system. It all started with a random unresponsive pedal and app codes at first. We threw an app in it because it seemed cut and dry. and it ran great for a day. Then got worse with surges, vgt malfunction, no start, and stalling. Only codes were app related. Then I broke out the schematic and found that it used one 5v reference. So I unplugged every sensor I could easily reach and bam, I had the right voltages on everything till I plugged the ebp.

I realize this is on a Ford and a lot of the sensors are non-existent on the Duramax but the same principal may apply. May want to find a schematic and bust out the meter haha

Sent from my SAMSUNG-SGH-I337 using Tapatalk

 

[Cornell]

Well gawd dam son, you'd never know your truck had ANY issues by lookin at it, I've always liked your truck, it's ridiculous. Glad to hear about the dipstick, at first read I was like, oh snap that can't be good, but further explanation made more sense, my PVC hose pinches a bit on the drivers side too :hug: I need to fab up my own makeshift air dam, it's been Down to 10*F and my heater doesn't blow to hot, my trans stays cold and my engine doesn't get to full operating temp for and hour, 15min warm up and 45 of mixed driving...negative side affects of the egr delete and heater grid delete I suppose.

Electrical gremlins are a bear and can happen anytime and anywhere, like the one you found 3' into the loom, I chased one in my buddy's suburban for like three days, turns out his wife climbed the console and pivoted on her heel in the same spot, for years, and that action damaged wires in the loom in the middle of the cabin more or less....PITA to figure that one out

KUDOS once again to you for the due diligence to figure out yet another electrical related issue....you must have a heated shop...

What was your buddy's wife doing climbing over the console? :roflmao:

I don't have an intake heater grid or EGR anymore either but my truck still warms up in 5 minutes in this cold weather with the winter front on. I left the truck outside last night. It seems like I have a short somewhere because of condensation but if its frozen the code doesn't come up. As soon as my cab heats up (10 minutes into driving) it throws the damn code again.

And yes I'm lucky, my Dad's shop that I work on my trucks in has heated floors.

I battled a similar issue on a 6.0 Powerstroke at work. Come to find out Ford used a common 5v reference wire to feed the ebp, egr, icp, and app sensor. The ebp got filled with coolant and shorted out wreaking havoc on the engine control system. It all started with a random unresponsive pedal and app codes at first. We threw an app in it because it seemed cut and dry. and it ran great for a day. Then got worse with surges, vgt malfunction, no start, and stalling. Only codes were app related. Then I broke out the schematic and found that it used one 5v reference. So I unplugged every sensor I could easily reach and bam, I had the right voltages on everything till I plugged the ebp.

I realize this is on a Ford and a lot of the sensors are non-existent on the Duramax but the same principal may apply. May want to find a schematic and bust out the meter haha

Sent from my SAMSUNG-SGH-I337 using Tapatalk

I'll have to look into that. I hate dealing with wiring and this truck has been a little bit of a pain as far as that goes.

 

[Dozerboy]

This must be the problem of the month. I just got one during some WOT runs today. I looked over the wiring cleared the code and now it won't set again... I didn't get a limp mode just a CEL.

I got a long trip next weekend and I'm working out of town this week. So I won't know if this was a one time thing until I leave. Better bring some tools fingers crossed.

 

[Cornell]

That's weird, my seemed to do it once the cab warmed up

 

[Dozerboy]

I drove the shit out of it for 1hr last night and couldn't get it to do it again. I checked the the Accelerator pid with EFI and it was in spec.

Its a bit colder up there then down here, and my truck sits in a nice warm garage.

 

[Cornell]

Mine sits in a warm garage too. Mine seemed to throw the code when cruising randomly. If I drive the truck hard it didn't throw the code

 

[Cornell]

Gotta bump this up again. It's been warmer (10-35 degrees) and the truck has been fine. Went and drove it today and it is -2 degrees out and it threw this code and limped out of nowhere.

Goofy as hell, I might just replace the harness for the pedal and see if that does it.

 

[Dozerboy]

Not had any problems here. Been driving a bit in weather 35*--2*.

 

[Cornell]

Yeah mine went away again now that it's in the 20s. I don't get it