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Discussion Starter · #1 ·
My DBW doesn't respond, and it's because I don't have the C1-14 & 15 wires hooked up. Where do they go? I have searched, but no luck.
The only drawing I have shows them going to the TAC, but the only wires I have is the short harness from the TAC on the pedal to the TB plug-in.

Thanks...
 

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The TAC module has 2 connectors. One is for the wires going to the pedal. The other is for the wires going to the PCM and the Throttle Body.

Are you saying you have the wires from the pedal going to the TB? What did your engine harness start life as?
 

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Discussion Starter · #3 ·
After further investigation, let me ask: howdo you "power" DBW if you don't use Cruise Control?
It looks like the TAC is used for DBW and CC together.
??

thanks...
 

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Discussion Starter · #4 ·
The engine, w/DBW, pedal assy. wiring harness.. everything all came off of a 2004 Silverado 2500 6.0L.

I have the harness from TB to pedal assy. but I don't know what actually "powers" it all. I don't have the TAC that mounts on the firewall, and I have the C!-14&15 wires from the PCM that go to ??.

thanks...
 

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How can the DBW function w/o a TAC.
Gas pedal is a sensor, that feeds to a TAC Module (Throttle Actuator Control) The TAC module monitors the gas pedal sensor, then commands the throttle body motor to set the desired throttle setting.
What number PCM are you using? 6242?
 

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What I'm saying is the wires don't go directly from the Throttle Body to the pedal. The TAC module is between them. PCM, TB, cruise, and power/ground wires go into one connector. The pedal wires go into the other.

You will need the TAC and will need to decide how to power it from your existing wiring. If your truck has the wiring for the cruise control module there are circuits in that connector that should cover all of your needs. I like to mount the TAC in the same location as the cruise module too. It has the same bolt pattern as the S10 cruise module and it's a good location for all the wiring needs.

Yes the TAC does both CC and throttle. If you don't want cruise you don't have to wire it up, but it's only a couple more wires on a truck setup for cruise.
 

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Discussion Starter · #7 ·
Is the TAC module a "reliable" component? I mean, can you buy a used one or just suck it up and buy the new one?
Also, does anyone have the harness that goes between the pedal and the TAC module? I only have the one from the TB.

I have the C!-14 & 15 wires from the PCM to power it, so it looks like the truck I got everything had the TAC module, they just didn't give it to me....RATS!
 

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All mine have been used and had no issues. I've sold about a dozen on eBay with pedals and had no complaints or returns.

Buy used. They're as reliable as the PCM from my experience. $30 is the price I'd try to beat if I were buying on eBay. They're about $15 at the pick n pull here. I'm sure they could be found cheaper depending on what the yard thinks it is.
 

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Discussion Starter · #9 ·
Just occurred to me. The TAC module isn't specific to the pedal assembly, is it?
If you just buy the TAC there isn't any "re-programming" involved, right?

Dumb question... ? But, I had to ask...
 

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Just occurred to me. The TAC module isn't specific to the pedal assembly, is it?
If you just buy the TAC there isn't any "re-programming" involved, right?

Dumb question... ? But, I had to ask...
Nope...plug & play.
 
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Better as @Harley on that. I thought there was more than one model TAC. If you pull one yourself at a yard try to get the connectors and as much harness as possible.
 

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Discussion Starter · #15 ·
OK, I have retrieved the original TAC module and pedal to TAC cable. (guy still had the “remains” of the truck everything else I have, came from). WOW!

Anyway, I installed everything and verified TAC wiring from PCM and “power” from UBEC –C2 was connected.

The engine will start, but will idle very low RPM and then dies. Fuel Pressure is 58psi. Throttle did not respond.

I did get a Po357 G code indicating a primary open, so I checked out the wiring and, just to see if maybe I had a bad coil, I switched the #3 & #7 coils and no more code. Good!

However, I then got a U0107 “Lost Communication with Throttle Actuator (TAC) Module”. I have the UBEC - C2 “power” wire plugged into the E7 position, which says, on the C2 pinout I have, it is an “ignition 1 Voltage” connection. I’m not sure I believe that. I thought I1V was a “hot on start/run” connection, but my suspicion is this is a “hot on start” (not run) connection.

Can someone briefly differentiate the terms, such as “ignition 1 Voltage”, “ignition”, etc., as far as when they’re “hot”? I’ve seen several C2 pinouts and they’re not all the same (seems possible).

Thanks …
 

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I suspect ignition 1 is from ENG 1 fuse.
Do you have the ground and brake pedal position (12V) wires connected to the TAC?
Click pic to see it larger.
352216
 

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E7 is a grounding pin on the S10.

@oldfogey47 remember that the Silverado and full size truck UBEC - C2 connector is not the same as the S10. You need to pin out your C2 to match the fuse panel you are using. I sent you over the right one (2003 2.2) and you should have permission to view it now. I'm looking at the Silverado pin out and that is where E7 is listed as ignition.
 

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Discussion Starter · #18 ·
Back when I had the initial "No-Crank" problem, I had the PCM ground in E7. I moved it to F7 and It then would crank, my headlights started working, and it was "trying" to run.
I've been looking at the C2 pinouts for several hours and this is what I now have:

A1 - A7 - not being used
A8 - Orn Batt (pcm C1 - 20&57)
A9 - MAF
A10 - PCM (C1-19)
B3 - not being used
B4 - DBW (TAC)
B5 - not being used
B7 - Fuel Pump Relay
B8 - B9 - not being used
B10 - coil packs 1 & 2
B11 - Gry Trans Range Sw(bkup lghts)
B12 - Lt Grn Trans Range Sw (P/N Pos sw signal)
C8 - Trans (pin 11)
C10 - Injectors (6 & 8)
C12 - Stop lamp Sw (C101 (D))
D3 - D4 - not being used
D10 - Injectors (2 & 4)
D11 - PPL Starter Solenoid
D12 - not being used
E2 - Trans. Crank Voltage (pin 12 NSS) <----------not sure about this one
E8 - Trans Power (pin 1 “round connector”)
E9 - not being used
E10 - Injectors (5 & 7)
F4 - not being used
F5 - not being used
F7 - PCM Ground
F9 - H02 Sensors (both)
F10 - Injectors (1 & 3)
F11 - Trans Range Sw (pin L NSS) (Strtr Relay coil sply voltage)

These are all the terminals in my C2
I've made several changes to try to "match" up. As you all know, I'm "challenged" in this area....

Thanks...
 

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After looking it over this is what I suggest you change. Some of it cleans it up and better packages the items on each circuit. The rest are what I see needing to be fixed. I put these in bold.

A9 - Coils Passenger Side
B9 - Coils Driver Side
B10 - MAF
B12 - NSS (9)
C8 - NSS (11)
E2 - NSS (12)
E7 - This needs to be spliced with the engine grounds and grounded to the engine - See schematic below
E8 - Don't get power for Trans here. Transmission Round Connector needs an Off/Run/Crank Voltage. This can be found in the C101 Connector Pin G. Splice together PCM - C1 (75) and Transmission Pin E together and terminate in C101 (G).
F7 - Ground to Engine - See schematic below
F11 - NSS (1)

352273


352272
 

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Discussion Starter · #20 ·
Just a quick one...
Does anyone have a pinout for both ends of the DBW cable from the pedal to the TAC unit? (2004 Silverado, 6.0L)
My pedal pinning doesn't exactly match the TAC end...

Thanks...
 
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