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Help P2101 Code

16K views 7 replies 2 participants last post by  IT_Pro 0115 
#1 ·
OK so I was working on my 2006 Envoy 4.2 today and disconnected the Bat. When I reconnected the Bat. it put its self into "limp" mode and now I can't get it out of it. I have both onstar and my local Advance Auto Parts running a OBDII scan. They have come up with about 10 diffrent codes indicating low voltage on almost ever component of my Envoy. The code that I can remember the most is P2101, they have me doing "run temp" cyles now. Any other suggestions??? I am racking my brain out and can't figure this out for the life of me.

Please HELP!!!:crazy:
 
#2 ·
What were you working on? Anything near the throttle body or fan clutch? "Reduced Engine Power" or limp mode usually happens when the accel pedal or throttle body sensors (2 are on each of those items) don't agree with each other. To prevent a runaway vehicle, there's redundancy in the sensors.

The reference voltage for those sensors also runs the fan clutch speed sensor, and a fa clutch or wiring harness short can also cause that sort of problem.

Or the ignition switch could have chosen to fail at this exact time, which can cause all sorts of erratic fault conditions involving low voltage.

Sure wish you had written down those codes. Now we're just guessing in the dark. You may need a trained mechanic with a good scan tool to talk to the vehicle and ask the systems what's wrong.
 
#3 ·
Codes I can get from Onstar (best $12 a month I spend for instances like this lol) Friday I did an oil change and a Sea Foam "hot soak" to the motor. I used the vacum port right next to the throttle body to inject the sea foam into the motor. It ran fine untill I disconnected the bat to install under body lights that were never installed I disconnected the bat but thats basiclly as far as I got as my 3 yr old would stop bouncing around so I scrapped the project, and reconnected the bat and was given the nice suprize of "limp" loss of power mode. I can get the other codes when I get home tonight and post in the AM. Hopefully this is a little more information that can assist you help me. I do tech support and I always tell my callers help me help you lol so I will do anything needed to help you help me lol :(
 
#4 ·
Ok so I called into Onstar this morning and here are the list of codes I have on the ECM.

P2101
P0973
P0976
P2764
C0240
P0443
P0787
P1682
P2769

Most of these codes are due to low voltage the esclation point in diagnostics told me. Hope this helps someone try to figure out what issue I am having

Thank you for any and all help with this!:crazy:
 
#6 ·
The orginal bat tested at 12.5 volts and 770 cca. I use to he a Parts Pro for Advance so I know someone of the people in the store so they swaped the bat out for me and tested the new one at 13.5 volts and 850 cca when I put it in. Just as a note the one on meter on the dash is reading around 11 when off and 13-14 when on (which should be alt reading). So I know there might me some inconsistancy there if that helps any.
 
#7 ·
Most of the DIY repairs of this sort require a meter and some electrical experience. Sounds like you don't own a hand held meter. On sale at Harbor Freight, they're sometimes as low as $1.99.

Your last post was the first time you mentioned you swapped batteries.

Anyway, that's a lot of codes. If you don't have a bad ignition switch (cheap and easy to replace) you have something deeper that will require a trained mechanic with a high-end scan tool to diagnose, I predict.

Start with the ignition switch.
 
#8 ·
The only reason the Bat was swapped was because the Onstar tech though I might have a bad bat but it was swapped after the whole issue appeared. I thought I would have to end up going to the dealer or mechanic but was just hopping there was something I over looked (one can wish lol).

Thank you for your help I will def be getting my own meter and look at the ingnition switch.

I will post once I know more from the dealer.
 
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