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BOBBYSS
BOBBYSS, Master Technician
Category: Chevy
Satisfied Customers: 17200
Experience:  ASE MASTER CERTIFIED, AA DEGREE AUTO/DIESEL TECH
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I had the same problem and I can't get it to clear. Any

Customer Question

I had the same problem and I can't get it to clear. Any advice? Also, when the battery was still week the locks flipped Locked/Unlocked. A full charge on the battery and that has gone away but Im getting the following codes.
P2138, P0641, P0452, P2135
Submitted: 1 year ago.
Category: Chevy
Expert:  BOBBYSS replied 1 year ago.

Hello, my name is Bobby. Thank you for the question. Can you tell me how the vehicle is running besides the light being on?

Customer: replied 1 year ago.
It's in limp mode. Shifts hard, doesn't accelerate well, won't go over 45mph.... the usual.
Expert:  BOBBYSS replied 1 year ago.

Thank you. Does it run like this every time you try to drive it or is it intermittent?

Customer: replied 1 year ago.
All the time.
Customer: replied 1 year ago.
It's all the time. I have an obd2 scanner and I am able to get the code cleared to where it doesn't show up the dash information, but the car still runs in limp mode. Also when I turn the key off and then start the car again it comes right back up on the dash reduced engine power. This all started after the battery got weak and I had to jump the car. I have tried unhooking the battery for 24 hours. I have actually tried a new battery but I took the new battery back because it didn't fix the problem and the one I have holds a full charge. I'm thinking is the body control module but because of the fact that it was fine until the battery got weak I want to make sure before I forkout that kind of money to the dealership. I've been told that the BCM has to be programmed by the dealership because they are VIN specific.
Expert:  BOBBYSS replied 1 year ago.

Thank you. It does sound like a BCM issue. This is common especially after a voltage failure. If you have a voltage meter we can run through some test before replacing this.

Customer: replied 1 year ago.
I do have a voltage meter
Expert:  BOBBYSS replied 1 year ago.

Great. That will help I also forgot to ask if your code reader also reads live engine data?

Customer: replied 1 year ago.
No. I just have a cheap Actron CP9125. It scans and erases, that's it. More than willing to buy a better one if need be.
Expert:  BOBBYSS replied 1 year ago.

Don't worry about that right now. The first thing I need you to do is unplug the connection at the throttle body and turn the key on and tell me which wires have voltage. I would then reconnect it and do the same at the throttle pedal under the dash.

Customer: replied 1 year ago.
sorry for the delay...I've been out of town. I am a little unsure if I used the Multimeter correctly. I had it set to DC and 2 V? If I need to redo this I will but will need instructions. Anyway, the results that I got were approx.(some of them were bouncing a little prob due to the cheap multimeter):Throttle pedal:Black/white: 1
Dark blue:.009
Brown: .004
Tan :.004
Light Blue:.199
Purple: .209Throttle BodyBrown:.026
yellow:.026
tan: .004
light blue: 1
purple: 1
Gray: .211
Tan/white: .004
Green .007
Expert:  BOBBYSS replied 1 year ago.

It looks like you did the test right, but you need to have it set on the 10v scale if it has one. The key needs to be on also.

Customer: replied 1 year ago.
I have a 200m,2,20,200,600
Customer: replied 1 year ago.
the key was on but the engine was not running
Expert:  BOBBYSS replied 1 year ago.

Thanks. Set it to 20 and retest.

Customer: replied 1 year ago.
OK same test set to 20
Black/white: 5.02
Dark blue: 0
Brown: 0
Tan : 0
Light Blue: 0.2
Purple: 0.2Throttle BodyBrown: 0.02
yellow: 0
tan: 0
light blue: 5.02
purple: 4.3 - 4.8
Gray: 0.20
Tan/white: 0
Green: 0
Expert:  BOBBYSS replied 1 year ago.

From those readings it looks like it is a bad switch.

Customer: replied 1 year ago.
Switch?
Customer: replied 1 year ago.
Do you mean the BCM?
Expert:  BOBBYSS replied 1 year ago.

Sorry. One more test just to verify the throttle body operation. If you place your meter between the brown wire and the yellow wire and then turn the key on and move the accelerator pedal do you get a voltage reading?

Customer: replied 1 year ago.
Do you mean making connection with the yellow and brown wire at the same time? If so how do I do this as the wires are sealed in the connector? Or did you mean to put the positive probe between the two wires where they are insulated to try to measure for bleed-through?
Expert:  BOBBYSS replied 1 year ago.

Let me clarify. Unplug the connector. Place one probe on one of the terminals and the other on the other terminal and tell me what the voltage reading is.

Customer: replied 1 year ago.
No voltage reading.
Expert:  BOBBYSS replied 1 year ago.

The fact that you are not getting any voltage there tells me that the PCM is not trying to operate the throttle body. If your scan tool has the capability then you need to see if you have a reading from the accelerator pedal position sensor.

Customer: replied 1 year ago.
My scanner can only read and clear codes.