Need some help with electric fans....2002 S10 5.3L

[10S10S]

2002 S10, has a 5.3L out of a 2002 Silverado, with the Silverado ECU (red and blue connector I believe).

Everything was working fine, had just worked the bugs out of the fuel gauge, speedometer and electric fans. Last weekend on the way home, the body control module (15095334) decided to let go. This truck had already blown a BCM pre-LS swap, so this was a replacement unit, same number.

Did the vats relearn by cycling the key 10 minutes at a time 3 times, etc.

Everything seemed fine except the electric fans come on as soon as Key turns on. Re-flashed the tune thinking replacing the BCM had lost part of the tune, but the fans still come on right away. Wrote the tune to the ECU and then read it back to make sure it stuck, and everything looked proper.

Also, if anyone could enlighten me on a B1001 Air Bag code, that'd be cool. I believe it's due to a mismatch in the VIN between the ECU and BCM. VIN change wizard doesn't seem to help.

PS: Trying to figure out how to attach tune file...seems to be an issue with Chrome

s10Feb24.hpt

[blindsquirrel]

New BCM or used from another vehicle? How did you program it?

BCMs are a one-shot-only deal with VIN programming, you can only enter a VIN once then it's that one forever.

[blindsquirrel]

#02-09-41-001: Info - DTCs B1001, B1271 or B1780 Set When Replacing/Reprogramming Other Modules - (May 24, 2002)

Subject: DTCs B1001, B1271 or B1780 Set When Replacing/Reprogramming Other Modules

Models: 1999-2003 Passenger Cars and Trucks
with Class 2 Serial Data Communication Between Modules


This bulletin is being revised to add model years and reflect changes in the Tech 2 procedure and filing classification. Please discard Corporate Bulletin Number 99-06-03-010A (Section 6 -- Engine).

Class 2 Serial Data Communication allows control modules (i.e. the Powertrain Control Module (PCM), the Body Control Module (BCM), the Dash Integration Module (DIM), the Instrument Panel Cluster (IPC), the radio, the Heating, Ventilation and Air Conditioning (HVAC) Controller, and the Sensing and Diagnostic Module (SDM) to exchange information. This information may be operational information or identification information. Among the identification information exchanged and compared within these modules is the Vehicle Identification Number (VIN). Typically the one module, the master module, broadcasts the VIN and all the other modules compare the VIN stored within itself. When the broadcast VIN does not match the VIN stored within the SDM, the following actions occur:
? DTC B1001 Option Configuration Error is set and deployment of the airbags is inhibited.
? DTC B1271 or a DTC B1780 Theft Locked.
The VIN information is also used by the radio. When the VIN does not match the VIN stored within the radio, DTC B1271 or DTC B1780 is set and the radio is inoperative.

Additionally, the master module will compare the SDM's part number (last four digits) to determine if the correct SDM is installed in the vehicle. If the SDM is the wrong part, a B1001 will also set.

This situation may occur when a vehicle is being repaired. When a PCM or a body control type module is replaced, the VIN information must be programmed into the replaced (new) control module. A module which has had VIN information entered into it (for example, one taken from another vehicle) cannot be reprogrammed. VIN information can only be entered into new modules. The ignition must be ON in order to program the control module. Since the VIN information is broadcast when the ignition goes to ON from any other ignition switch position, DTCs may be set in the SDM and/or the radio. Therefore, always follow the specified control module replacement procedures.

After completing the repair, turn OFF the ignition for at least 30 seconds.
Turn ON the ignition and check for DTCs using a Tech 2? scan tool.

If DTCs B1001, B1271, or B1780 are present with a history status, DO NOT REPLACE THE SDM OR THE RADIO.
Clear the DTCs from all modules using the Tech 2 scan tool.
Remove the Tech 2? from the vehicle
Ensure the proper operation of the SDM by turning OFF the ignition and then turning ON the ignition. The air bag warning indicator should flash seven times and then go OFF.

Refer to Corporate Bulletin Number 99-09-41-001 for additional information regarding proper reprogramming of the new/replaced module.

Clearing codes from the other modules is part of the replacement and reprogramming procedure for the replaced module. The repair is not complete unless all codes have been cleared from all modules.

DO NOT SUBMIT CLAIMS FOR OTHER MODULE REPLACEMENTS OR REPROGRAMMING.

[10S10S]

New BCM or used from another vehicle? How did you program it?

BCMs are a one-shot-only deal with VIN programming, you can only enter a VIN once then it's that one forever.

Both BCMs were junkyard from other vehicles.

I don't recall it sending an Air Bag code/light with the first replacement, so that's interesting......

[TheMechanic]

Here you go. This is likely your issue
#PIC5913: Diagnostic Tip - B1001 With SIR MIL And/Or SVS MIL And/Or Locked Radio - (Sep 19, 2013)
Subject: Diagnostic Tip - B1001 With SIR MIL And/Or SVS MIL And/Or Locked Radio

Models: 1998-02 Chevrolet Astro, Venture, S10, Blazer, Trailblazer, Camaro, Cavalier, Corvette, Impala, Monte Carlo, Lumina, Malibu, Metro, Prizm, Express
1998-02 GMC Safari, Savana
1998-02 Pontiac Bonneville
1998-02 Pontiac Firebird Models, Sunfire, Grand Am, Grand Prix, Montana
2001-02 Pontiac Aztek
1998-99 Buick Riviera
1998-02 Buick LeSabre, Park Avenue, Century, Regal
2002 Buick Rendezvous
1998-99 Oldsmobile Cutlass
1998-02 Oldsmobile Bravada, Aurora, Intrigue, Alero
1998-02 Cadillac DeVille, SeVille, Eldorado, STS, SLS, Catera, Escalade Models
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern
Some vehicles may exhibit a B1001 DTC with an SIR lamp, SVS lamp on and/or radio locked, possibly after module replacement (i.e. BCM, SDM, etc.). This information is presented to clarify the failure modes that will set this DTC, as well as offer a diagnostic direction to help repair them.

DTC B1001, by definition, is a "configuration mismatch" between vehicle modules that communicate with each other over a data line. Modern vehicle systems depend upon each module storing certain vehicle information, as well as information about other modules in order to work properly together. Common causes of B1001 are:

1. An incorrect or non-existent VIN number in modules that require them.
2. A module that has been replaced but not programmed per currently published service information.
3. SDM replacement where the new SDM is a different (newer) part number than the original.
Recommendation/Instructions
A common diagnostic approach that will address most concerns with B1001 is as follows:

1. Ask the technician if a module has recently been replaced which led to the B1001 DTC. If so, determine if the service information procedure for replacing the affected module has been followed. For example, some callers mistakenly believe that a new BCM simply requires "theft deterrent relearn" to operate properly. However, many modules require a "new module setup/RPO configuration" procedure to operate properly. The process for setting up a new module varies, consult currently published service information for the correct procedure for your application.
2. If an SDM has recently been replaced, the BCM requires the last 4 digits of the SDM part number to be stored in a portion of the BCM to prevent DTC B1001. If the SDM's service part number is different than the original module, a special procedure is required to erase and re-learn this "restraints ID" code in the BCM. While the procedure varies from vehicle to vehicle, there are two standard methods as follows:
2.1 On some vehicles the Tech 2 has a function available in the BCM or SIR "Special Functions" menu. Common terminology is "setup SDM part number in BCM" or similar nomenclature. Follow on-screen instructions to complete procedure.
2.2 Some vehicles require an "SPS" method of programming the restraints ID. Perform the "Request Info" step at the vehicle and confirm the VIN number stored, then take the Tech 2 back to the terminal and down-load the appropriate file from the TIS2WEB "available modules" menu.
3. If neither of the above are successful in clearing B1001, check the following modules with the appropriate Tech 2 data list under "VIN" or "module information" to determine if the correct VIN number is stored.
PCM: If the PCM does not have a VIN stored, or the incorrect VIN is stored, it will be necessary to program the PCM using the current SPS method. If the PCM already has the latest calibration software installed, it will be necessary to contact Techline Customer Support Center (TCSC: 1?800?828?6860 English or 1?800?503?3222 French) and request a VCI number to allow reprogramming with the same calibration.

BCM: If the BCM does not have a VIN stored, or the incorrect VIN is stored, it will be necessary to install the correct VIN using the appropriate line under the BCM's "special functions" menu. Follow on-screen prompts to complete programming.

Radio: If the Radio does not have a VIN stored, or the incorrect VIN is stored, it will be necessary to install the correct VIN using the appropriate line under the radio's "special functions" menu. Follow on-screen prompts to complete programming.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

[TheMechanic]

Long story short it is likely the VIN needs to be programmed into the BCM

[TheMechanic]

#02-09-41-001: Info - DTCs B1001, B1271 or B1780 Set When Replacing/Reprogramming Other Modules - (May 24, 2002)

Subject: DTCs B1001, B1271 or B1780 Set When Replacing/Reprogramming Other Modules

Models: 1999-2003 Passenger Cars and Trucks
with Class 2 Serial Data Communication Between Modules


This bulletin is being revised to add model years and reflect changes in the Tech 2 procedure and filing classification. Please discard Corporate Bulletin Number 99-06-03-010A (Section 6 -- Engine).

Class 2 Serial Data Communication allows control modules (i.e. the Powertrain Control Module (PCM), the Body Control Module (BCM), the Dash Integration Module (DIM), the Instrument Panel Cluster (IPC), the radio, the Heating, Ventilation and Air Conditioning (HVAC) Controller, and the Sensing and Diagnostic Module (SDM) to exchange information. This information may be operational information or identification information. Among the identification information exchanged and compared within these modules is the Vehicle Identification Number (VIN). Typically the one module, the master module, broadcasts the VIN and all the other modules compare the VIN stored within itself. When the broadcast VIN does not match the VIN stored within the SDM, the following actions occur:
? DTC B1001 Option Configuration Error is set and deployment of the airbags is inhibited.
? DTC B1271 or a DTC B1780 Theft Locked.
The VIN information is also used by the radio. When the VIN does not match the VIN stored within the radio, DTC B1271 or DTC B1780 is set and the radio is inoperative.

Additionally, the master module will compare the SDM's part number (last four digits) to determine if the correct SDM is installed in the vehicle. If the SDM is the wrong part, a B1001 will also set.

This situation may occur when a vehicle is being repaired. When a PCM or a body control type module is replaced, the VIN information must be programmed into the replaced (new) control module. A module which has had VIN information entered into it (for example, one taken from another vehicle) cannot be reprogrammed. VIN information can only be entered into new modules. The ignition must be ON in order to program the control module. Since the VIN information is broadcast when the ignition goes to ON from any other ignition switch position, DTCs may be set in the SDM and/or the radio. Therefore, always follow the specified control module replacement procedures.

After completing the repair, turn OFF the ignition for at least 30 seconds.
Turn ON the ignition and check for DTCs using a Tech 2? scan tool.

If DTCs B1001, B1271, or B1780 are present with a history status, DO NOT REPLACE THE SDM OR THE RADIO.
Clear the DTCs from all modules using the Tech 2 scan tool.
Remove the Tech 2? from the vehicle
Ensure the proper operation of the SDM by turning OFF the ignition and then turning ON the ignition. The air bag warning indicator should flash seven times and then go OFF.

Refer to Corporate Bulletin Number 99-09-41-001 for additional information regarding proper reprogramming of the new/replaced module.

Clearing codes from the other modules is part of the replacement and reprogramming procedure for the replaced module. The repair is not complete unless all codes have been cleared from all modules.

DO NOT SUBMIT CLAIMS FOR OTHER MODULE REPLACEMENTS OR REPROGRAMMING.

Looks like we hit reply at the same time. Hahahaha

[10S10S]

Long story short it is likely the VIN needs to be programmed into the BCM

Will the VIN also affect the Fan problem I'm having? The Fans seemed to work normally with the previous BCM, which was also from a different truck.

[TheMechanic]

It is possible. Don't have my laptop with me today to check your RPO's. Possible you have something without A/C or other option that does not have electric fans. As in viscous clutch arrangement.

[blindsquirrel]

I'm having a hard time finding any docs in eSI for a Silverado PCM, in a S10, with electric fans.

[TheMechanic]

I'm having a hard time finding any docs in eSI for a Silverado PCM, in a S10, with electric fans.

Was thinking of using "investigate vehicle history" and going off of both VIN's to see RPO's of both, compare them and see if a potential programming fix may cure the issue. I was figuring that possibly a configuration error between the original BCM and the used one may shed some light. Just a guess on my part since this is new territory.

[10S10S]

If I’m following correctly....

Would HP be able to scan the VIN that’s stored in the BCM and reprogram the ECU to match?

Or am I better off getting ahold of a new BCM and programming it to match the truck. I will admit I figured all the BCM were the same so long as the numbers matched.

[blindsquirrel]

There are two separate things here, one is the SDM Key mismatch thing which I think is easily fixable (with the right scan tool). The overall BCM setup/config/programming is what I have no clue about. You have a S10 BCM which is expecting to find a S10 VIN on the other end of the line, and it's never going to be there. And the PCM is expecting to find a Silverado VIN at the BCM, that ain't going to happen either since the BCM is plugged into S10 hardware throughout the truck, not Silverado hardware.

[2xLS1]

E-fans would have been added to a 02 S10. This is a swap vehicle too. The S10 BCM would have nothing to do with added E-fans. !00% controlled by the PCM.

[10S10S]

E-fans would have been added to a 02 S10. This is a swap vehicle too. The S10 BCM would have nothing to do with added E-fans. !00% controlled by the PCM.

This was my understanding as well, and everything fan wise was working prior to BCM swap. So I'm puzzled as to why the fans power up instantly with keyed power now.

[2xLS1]

Fans are 100% independent of the BCM.

[blindsquirrel]

So it's just a coincidence then? I suppose it's possible there was some common fault/failure that affected both the fan operation and killed the BCM* at the same time. That's more plausible than a real true actual coincidence where two totally unrelated things happen at the exact same time.

*BCM 'failures' can be tricky things, most of the time there's no way to know anything other than 'it doesn't work anymore'. I got into the habit of opening the case and inspecting the board & components for any modules where that was possible (snap-together case, non-potted).

[blindsquirrel]

Do the fans power up at key-on with the PCM unplugged? How about with just the BCM unplugged?

[2xLS1]

OP, describe your fan harness. GM or aftermarket? If aftermarket, 2 trigger wires going to PCM or one wire to PCM and one wire to AC compressor? Using 3 relays for both low speed and high speed fan control?

[10S10S]

Do the fans power up at key-on with the PCM unplugged? How about with just the BCM unplugged?

Ok, had a chance to do some further investigating.

PCM unplugged nothing powers up. BCM unplugged, fans still power up when key turned on.

OP, describe your fan harness. GM or aftermarket? If aftermarket, 2 trigger wires going to PCM or one wire to PCM and one wire to AC compressor? Using 3 relays for both low speed and high speed fan control?

It's an aftermarket harness made by Current Performance Wiring. Custom made for this truck, for this swap, with these options. Only, two fan relays on the firewall. Not sure about the trigger wires.

Fan relay 1 is the one that is powering up. Control circuit pink wire seems to be constant power continuity tests to PCM blue connector, pin 19. Ground is a blue wire, pin 17, also seemingly constant.

If I pull the Ignition A (40 Amp maxi in the fuse box), the fans don't power up.