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Gary, Technician
Category: Car
Satisfied Customers: 17006
Experience:  GM master tech for 15 years/ASE master tech for 20 years
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Security Light Flashing Code P2948 How To Get The Light Ou

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Security Light Flashing Code P2948 How To Get The Light Out.

transman :

Hi can you tell me the model , make and year ?

JACUSTOMER-edg9bw3a- :

2000 Chev S10 Pick-up 2.2 L

JACUSTOMER-edg9bw3a- :

Has DTC B2948

transman :

ok give me two minutes

JACUSTOMER-edg9bw3a- :

You still there?

transman :

sorry for the delay was there a key replace or a body computer replace on this vehicle?

transman :

at this moment you have a problem with the body computer ascepting the key transponder located on the key.

transman :

this can happen when the transponder diode on the key is worn weak or broken ,and when the body computer or the engine controller has been replase.

transman :

to reset this you will need a new key with the new transponder key and a scanner to progranm it in to your BCM and PCM.

JACUSTOMER-edg9bw3a- :

Ok no parts have been replaced, except the timing chain had jumped.A year ago I had a DTC B2947 The passlock sensor was not getting the 12v from the BCM. I gave it 12v from an ignition on source and it worked fine untill we changed the timing chain. I have tried the other spare key same thing. You think I can change the BCM for a used one and then do the 'password XXXXX"?

JACUSTOMER-edg9bw3a- :

Hello, anybody home???

JACUSTOMER-edg9bw3a- :

Hello. where is the answer

My name is XXXXX XXXXX I will try my best to help you with your vehicle issue.

Sometimes internet connection or computer issues or converting a conversation from chat to Question & Answer bounces the expert off the site and we have to "reset".

Please hold tight for transman to get back to you.

He is automatically notified when you post a question on this thread.

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Thanks for your patience,


Hi sorry i lost you last night i don't know what happen but here i am, if you had to provide the 12volts to the key sensor then the body computer is at fault and needs replacement ,bypassing the body computer works ok until you had to disconnect the battery for more then one hour this will drain all capacitors keeping memory alive and reset everything again and at this point you would need the rolling code # XXXXX be reprogram back in to the body computer but if you have no power output from the body computer then you will need one, i will suggest to remove the bypass to the key sensor and replace the body computer and then reset the security system as follows on the next page.
wans you replace the body computer open the drivers side door and lock all other doors insert the key to the ignition turn the key to on leave the key to the on position for one hour you will need to maintain the battery charge for this period of time with a charger at low charge, then after one hour open the door turn the key to the off then turn ot start.
Customer: replied 4 years ago.

So can I use, a used BCM, and do the relearn procedure? Remember now, I'm getting a DTC B2948. When i measured the voltage on circuit 1836 i was getting 5V. So, is it the BCM, or the passlock sensor ?? Or Both. Can we use, used parts????

Customer: replied 4 years ago.

My last question was, can I use, a used BCM, and do the password XXXXX procedure?

Customer: replied 4 years ago.
Relist: Inaccurate answer.
I want to know if I can use, a used BCM, and perform the relearn procedure.
new expert here did you still need help ?
Customer: replied 4 years ago.

Yes I need some answers to my questions,


yes you can use a used BCM BUT ! the used BCM must be programed with a scan tool to the VIN number of your truck and set up with a scan tool

the VIN number and set up will not work without reprograming it to the trucks VIN number

hands down this truck either has bad wires from the BCM to the passlock sensor,bad passlock sensor or a bad BCM

the testing for the 12 volts from red/white wire testing at the passlock connector with it unplugged on the harness side wires

you must use a multi meter with a MIN MAX you need to set the MIN MAX peak to I millisecond then run the record on the meter and shut the key off see if it reads close to 0 volts the problem is the passlock sensor

if it reads more than 0 volts then either the wires to the BCM are bad or the BCM is bad

if it reads 0 all the time

Gary, Technician
Category: Car
Satisfied Customers: 17006
Experience: GM master tech for 15 years/ASE master tech for 20 years
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