ISO on C2 pin 19 information for a 2001 Chevy Silverado 1500 4x4

[Roadstar01]

Can anyone tell me where the black and white stripe wire that is supposed to be assigned to PCM C2/red connector pin number 19 goes to or comes from? I cannot find a spaghetti one line diagram for the PCM for either C1 or C2 connectors. Thank you for any help you can provide.

[Jsdirt]

Not sure on a '01, but on a '99 that is circuit 1695 for the 4x4 front axle switch. Good chance it;s the same.

[Roadstar01]

15 hours ago, Roadstar01 said:

Can anyone tell me where the black and white stripe wire that is supposed to be assigned to PCM C2/red connector pin number 19 goes to or comes from? I cannot find a spaghetti one line diagram for the PCM for either C1 or C2 connectors. Thank you for any help you can provide.

Yes indeed 1695 is the circuit. I just need to know the routing of that circuit. I have the Black/ White stripe wire located at the Front Actuator as one the 4 wire connections and it appears to be coming from the Transfer Case Control Module Pin E14 which is addressed as 4WD WHL Lock and is part of 1695 Circuit.

However on the PCM C2/Red connector there is no Black/WHT Stripe wire landed on Pin 19 which is also 1695 circuit.  Where does that leg too the PCM pin originate from or land too?

 

Update...

What I found when doing research on the 1695/Blk and wht stripe wire at actuator and this is why I need to get the #19 PIN connected to complete the circuit for this system to perform:

        On a 2001 Chevy Silverado, a black and white signal wire will typically receive 12 volts when the front actuator is engaged, signifying that the front axle is now in four-wheel drive mode, meaning the front wheels are actively powered.
• Signal Wire Function: This black and white wire acts as a "switch" signal, sending voltage to the vehicle's computer when the actuator is activated, allowing it to display the appropriate information on the dashboard (like a 4WD light) and potentially adjust other vehicle systems accordingly.
• Voltage Indication: When the wire receives 12 volts, it means the actuator has engaged, and the front axle is now connected to the drivetrain, enabling four-wheel drive.
 

Edited January 2, 2025 by Roadstar01

[newdude]

11 hours ago, Roadstar01 said:

Can anyone tell me where the black and white stripe wire that is supposed to be assigned to PCM C2/red connector pin number 19 goes to or comes from? I cannot find a spaghetti one line diagram for the PCM for either C1 or C2 connectors. Thank you for any help you can provide.

 

 

Which transfer case do you have?  Floor shift?  Push button with 2HI, 4HI and 4LO?  Or the Autotrac with AUTO mode?  

[Roadstar01]

1 hour ago, newdude said:

 

 

Which transfer case do you have?  Floor shift?  Push button with 2HI, 4HI and 4LO?  Or the Autotrac with AUTO mode?  

I wish the answer was simple.

I am using the 4 button control panel from donor truck, do not believe the NP246 TC is of the Autotrac family. Would be nice to wire in the Auto 4WD button capability but the more I read the more I see Chevy/GM did no favors in the design of A4WD and often causes a catastrophic loss to the the 4x4 system.

So I have swapped a NP246 Transfer Case and TCC Module and associated wiring from a 2001 Chevy Silverado donor. The front differential is from a 2003 ZR2 Chevy S10 which uses a Vacuum Actuator and is installed. I have the vacuum electric solenoid connected to the 3 of the 4 wires meant for the Silverado front diff. The wires I am using so far from the Silverado front actuator motor which is successfully triggering the S10 front differential vacuum solenoid are: Brown = ignition 12v, Black = Ground, Light blue is a signal wire which I used for the ground signal on a relay which is closing the relay to send 12 volts to the electric solenoid when put in 4WD. The wire I am not using "yet" is the Black and white 1695 circuit wire. Everything worked great until my Check AWD service light came on and now the front diff is not receiving power from the Transfer case.  The encoder motor is still working and 4H, 4L, 2H and Neutral is still online. So without a complete 1695 circuit, I now assume the clutch pack in the TC is not locking up to send the torque through front drive shaft to differential. Also the Safari has a V8 swap and using a 2001 Chevy Tahoe PCM.  Clear as Mud?

Edited January 2, 2025 by Roadstar01

[newdude]

48 minutes ago, Roadstar01 said:

I wish the answer was simple.

I am using the 4 button control panel from donor truck, do not believe the NP246 TC is of the Autotrac family. Would be nice to wire in the Auto 4WD button capability but the more I read the more I see Chevy/GM did no favors in the design of A4WD and often causes a catastrophic loss to the the 4x4 system.

So I have swapped a NP246 Transfer Case and TCC Module and associated wiring from a 2001 Chevy Silverado donor. The front differential is from a 2003 ZR2 Chevy S10 which uses a Vacuum Actuator and is installed. I have the vacuum electric solenoid connected to the 3 of the 4 wires meant for the Silverado front diff. The wires I am using so far from the Silverado front actuator motor which is successfully triggering the S10 front differential vacuum solenoid are: Brown = ignition 12v, Black = Ground, Light blue is a signal wire which I used for the ground signal on a relay which is closing the relay to send 12 volts to the electric solenoid when put in 4WD. The wire I am not using "yet" is the Black and white 1695 circuit wire. Everything worked great until my Check AWD service light came on and now the front diff is not receiving power from the Transfer case.  The encoder motor is still working and 4H, 4L, 2H and Neutral is still online. So without a complete 1695 circuit, I now assume the clutch pack in the TC is not locking up to send the torque through front drive shaft to differential. Also the Safari has a V8 swap and using a 2001 Chevy Tahoe PCM.  Clear as Mud?

 

 

Actually that was pretty helpful haha.  So an 01 Tahoe PCM and then t-case and TCCM from an 01 Silverado.  

 

Let me see what I can come up with.  

[Roadstar01]

52 minutes ago, newdude said:

 

 

Actually that was pretty helpful haha.  So an 01 Tahoe PCM and then t-case and TCCM from an 01 Silverado.  

 

Let me see what I can come up with.  

The LS swap happened a couple years back, and i figured why stop there, as if that was not a large enough headache, so more self inflicted pain,,, hey let's get 4WD Low capability to help pull loads out of the bottom of hills.  So now having a cast iron cased front diff with a truck Transfer case.  now just have one last thing to complete and that is fool the PCM, transfer case and control module to believe there is a OEM front 4 wire differential actuator motor at the end of the circuits BLK/Whit wire 1695 and light blue wire 1296.

Edited January 2, 2025 by Roadstar01

[Jsdirt]

This right here is why I LOATHE electronics. Just one big PITA.

[Roadstar01]

makes 2 of us.  but when "everything" is 100% it runs hard.  unfortunately all my pain and suffering is self inflicted,, i can't leave well enough alone, call it school of hard knock,, maybe my dad was onto something haha

[newdude]

4 hours ago, Roadstar01 said:

I wish the answer was simple.

I am using the 4 button control panel from donor truck, do not believe the NP246 TC is of the Autotrac family. Would be nice to wire in the Auto 4WD button capability but the more I read the more I see Chevy/GM did no favors in the design of A4WD and often causes a catastrophic loss to the the 4x4 system.

So I have swapped a NP246 Transfer Case and TCC Module and associated wiring from a 2001 Chevy Silverado donor. The front differential is from a 2003 ZR2 Chevy S10 which uses a Vacuum Actuator and is installed. I have the vacuum electric solenoid connected to the 3 of the 4 wires meant for the Silverado front diff. The wires I am using so far from the Silverado front actuator motor which is successfully triggering the S10 front differential vacuum solenoid are: Brown = ignition 12v, Black = Ground, Light blue is a signal wire which I used for the ground signal on a relay which is closing the relay to send 12 volts to the electric solenoid when put in 4WD. The wire I am not using "yet" is the Black and white 1695 circuit wire. Everything worked great until my Check AWD service light came on and now the front diff is not receiving power from the Transfer case.  The encoder motor is still working and 4H, 4L, 2H and Neutral is still online. So without a complete 1695 circuit, I now assume the clutch pack in the TC is not locking up to send the torque through front drive shaft to differential. Also the Safari has a V8 swap and using a 2001 Chevy Tahoe PCM.  Clear as Mud?

 

 

 

246 is the Autotrac case.  261 and 263 are regular 4x4.  

[newdude]

3 hours ago, Roadstar01 said:

The LS swap happened a couple years back, and i figured why stop there, as if that was not a large enough headache, so more self inflicted pain,,, hey let's get 4WD Low capability to help pull loads out of the bottom of hills.  So now having a cast iron cased front diff with a truck Transfer case.  now just have one last thing to complete and that is fool the PCM, transfer case and control module to believe there is a OEM front 4 wire differential actuator motor at the end of the circuits BLK/Whit wire 1695 and light blue wire 1296.

 

 

Here's the schematics for NVG246 Autotrac setup for 2001.  Two PDFs below, hopefully they open for you okay.  

 

TCASE POWER, GROUND AND SIGNALS.pdf

 

PCM DATA SHOWING TCASE LOW RANGE SIGNAL.pdf

Edited January 2, 2025 by newdude

[Roadstar01]

36 minutes ago, newdude said:

 

 

Here's the schematics for NVG246 Autotrac setup for 2001.  Two PDFs below, hopefully they open for you okay.  

 

TCASE POWER, GROUND AND SIGNALS.pdf 85.72 kB · 0 downloads

 

PCM DATA SHOWING TCASE LOW RANGE SIGNAL.pdf 93.68 kB · 0 downloads

TY so much for looking into this.  Not finding many to engage with me on this.  Here is the one line NP246 TC wire diagram and I marked those areas to look at at it relates to circuit 1694, I landed the grey/Black wire on C2 #16 and TCCM F7 4WD Low circuit 1694. The second attachment hopefully is the PCM pinout for a 2001 Sierra/Silverado etc. Please look specifically at the C2/Red colored pin out and pin #19 is specifically for circuit 1695.  Also pin 16 is 1694. I wish I could find the PCM wire diagrams showing specifically the PCM interface with the TCCM and front actuator and Transfer case.

NP246 Wire Diag .docx C1 and C2 PCM Pinouts for 2001 Chevy Silverado.docx

[Roadstar01]

13 minutes ago, Roadstar01 said:

TY so much for looking into this.  Not finding many to engage with me on this.  Here is the one line NP246 TC wire diagram and I marked those areas to look at at it relates to circuit 1694, I landed the grey/Black wire on C2 #16 and TCCM F7 4WD Low circuit 1694. The second attachment hopefully is the PCM pinout for a 2001 Sierra/Silverado etc. Please look specifically at the C2/Red colored pin out and pin #19 is specifically for circuit 1695.  Also pin 16 is 1694. I wish I could find the PCM wire diagrams showing specifically the PCM interface with the TCCM and front actuator and Transfer case.

NP246 Wire Diag .docx 501.41 kB · 0 downloads C1 and C2 PCM Pinouts for 2001 Chevy Silverado.docx 1.4 MB · 1 download

To no surprise, I am finding a conflict in diagrams from different sources. The one you sent me is the 1st time I seen that PIN 19/1695 was for a different TC model.  Not say it was not written in the other hundreds of diagrams I have sifted through.  At my age I can look right at something and not see it.  Called Olditis I think

[newdude]

2 hours ago, Roadstar01 said:

To no surprise, I am finding a conflict in diagrams from different sources. The one you sent me is the 1st time I seen that PIN 19/1695 was for a different TC model.  Not say it was not written in the other hundreds of diagrams I have sifted through.  At my age I can look right at something and not see it.  Called Olditis I think

 

 

These are right from the GM service manual.

Edited January 3, 2025 by newdude

[Jsdirt]

Wouldn't be the first time the manual was wrong. Seems to be very common lately!

 

I think they do this on purpose sometimes - they'll issue updates to replace certain pages of a wiring diagram (or other error) to dealerships, so if a private, non-dealer shop isn't right on top of it, or a consumer buys a manual for himself, you'll never get the notification that there was a correction. Then down the rabbit hole everyone goes. It's infuriating!!

 

Everything is electronic these days so they probably only issue corrections to dealers.

 

Another of MANY reasons I got out of the industry. 

Edited January 3, 2025 by Jsdirt