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I fixed "P0093" code on 01 Lb7 FINALLY!

PawPawtruck01

PawPawtruck01

Member
Messages
35
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80
Location
Pilot Mountain N.C.
Howdy yall. I bought my dream truck about 3 months ago. 01 Lb7 dually. Along with it, the dreaded "P0093" code, and limp mode mainly while going up a hill or towing. Lomg story short, after doing everything but injectors, "I was told they were done bot even a year ago" it STILL put me in limp mode. I done fuel lines, filters, bypass filter housing, FPR, FPRV mod, tuning, lift pump etc, still no luck...I was frustrated and dome some reading on the 'bugs" that the 01's have in the tuning. So, the other day I read about the BARO sensor, and what it does. It supposedly adjusts fuel trim depending on the readings it gets, and they can get wonky sometimes. I unplugged the sensor, and FINALLY, the actual rail pressure would keep up with the desired pressure..blew my mind. But, the baro sensor is tied in with the map sensor "boost gauge" and they didn't work. So, I made a splice in the oarngish/ red wire, and put it on a switch so I could cut the signal of it, but still have it plugged in and the baro gauge work along with the map sensor....works like a charm..with the switch off, the truck runs like it should, no issues, no limp, no de fueling, etc. Blows my mind why or how this worked, but it did! Maybe it will help someone with this issue. I will include some pics of what I done to get rid of the limp mode. Maybe a new baro sensor would fix it, maybe it's bad. Maybe it's "Maybelline" lol but it worked for me. And I'm leaving it ALONE! LOL By the way, my EGT'S are down also on average 100 degrees. And I'm running an edge tuner on tow mode, and using the monitor to watch parameters. I also have an analog boost gauge and pyrometer I installed. Hope this helps somebody. Much respect.
 

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Cutting that sensor is putting you in to engine protection mode, so it is not fueling as much, that is why your rail pressure is now holding. Has the ECM been updated? There was many problems with early OS's setting rail pressure and boost codes for no reason. Otherwise you need to have a return rate test done to see where the fuel is bypassing.

And "new injectors" does NOT mean good injectors. So many "remans" are worse than 150k mile worn out injectors it's unreal.
 
Well. As I said, now, when it demands 21k, it will hold 21k. When it wants 22.5k it'll hold 22.5k. No engine light, no codes. Pulls like a train. Whatever the TPS tells it to do it will do. If it's indeed in engine protection mode, there will be "thresholds" on all parameters. I'd like to know what they are if so. Cause it does what it's asked to do now. At times, I can mat it, it'll demand 22kish and it'll do 22kish. Till I let out. I ain't arguing, it's just weird. It's like the TPS is not sending riggt signal, or communication is being lost somewhere, whether it be at the FPR and it thinks it's at the number it's supposed to be. Either way, now it runs as normal as my 03 LB7. That truck never commanded 21k rail pressure at not even quarter throttle like this one when I have the switch in normal mode. I flip switch, cut that one circuit, and all is well. Digital boost gauge still works, baro sensor still works and reads as it should etc. Thanks.
 
I am curious if when these systems are put into protection mode if there is a code set or something to look for in the data stream to tell when it is.

you should be able to bring up the ecm info on the scanner to read the programming code serial number or whatever it's called and run it by the dealers info to see if that's the problem child software and needs to be updated.
 
dbrannon79 said:
I am curious if when these systems are put into protection mode if there is a code set or something to look for in the data stream to tell when it is.

you should be able to bring up the ecm info on the scanner to read the programming code serial number or whatever it's called and run it by the dealers info to see if that's the problem child software and needs to be updated.
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Me too. Like I say, there are no codes "that I know of" in the tuner etc. I should go by a dealer and have it checked for any codes with their big fancy scanner. Could be. Who knows lol.
 
look around your area for an individual or mom n pop shop who has a GM Tech 2 scanner. if they have one great, if they are subscribed to GM's services they'll also be able to check if there is an update and flash the update for you at a fraction of the cost the stealership would charge! unless of course you have a buddy working at a local chevy house lol
 
dbrannon79 said:
look around your area for an individual or mom n pop shop who has a GM Tech 2 scanner. if they have one great, if they are subscribed to GM's services they'll also be able to check if there is an update and flash the update for you at a fraction of the cost the stealership would charge! unless of course you have a buddy working at a local chevy house lol
Click to expand...
Ok will do.
 
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