P59 and TAC issues Please help me get this rolling

lots to cover so ill try to keep this to the point, vehicle is a 05 Colorado with 4.8l, 4l80e, 2006 express van ecu and harness with 3 bar os. i purchased a 2006 TAC module and Harness assembly. i then purchased a 2006 envoy/trailblazer pedal assembly as that's what fits in my vehicle physically. i constantly get code U0107 lost comm with tac if i go over 40% throttle or make quick blips of the throttle. ive verified tac module grounds, ignition power, battery power, etc. swapped in another known good 2006 tac module, bought a replacement pedal harness, tried other 2006 pedals. same thing happens every time. I'm at a loss at this point and only thing i can reason is that the etc limits within the tune or something else is hanging me up. it seems that the app sensors in the pedal are seeing ranges the tac doesn't like. but tracking down that info on what ranges should be has been nearly inpossible, i found data for the older 3 APP sensor pedal assemblies and tested my assemblies to see how the APP sensors read to eachother, and the numbers are all very very different. so that diag was pointless. any input or direction is much appreciated, I'm a HP forum noob so if you want my log or tune file to review just lmk how i go about posting it and ill gladly do so. thank you, matt

PS. truck runs and drives just fine and all other minor tuning tweaks have been a non-issue as long as i stay under 40% throttle.

I'd think the van pedal would be wanted because you are using the van computer with van DBW, TAC and harness.

The trailblazer pedal assembly may use different part numbers than what the van does and now you get an issue.

That problem happens when the OS in the PCM is not compatible with the TAC module.
There are 3 types of TAC modules for Gen3 truck engines. What did the TAC come from? Post a picture of the part number
For your application I would use a 03-05 metallic pedal (cut and weld to fit) with matching TAC and Throttle. This setup is the most common for Gen3 trucks.

working a double so ill get pics of everything tomorrow evening. for what ive read all TACs from 02-06 work together. i could see the pedal being an issue as its from a 06-07 trailblazer but i haven't found anything stating it wont until you all mentioned the OS. ill get that of my tuning laptop and post as well so we can see what might cause this. i have the pedal that came with the harness and ecu but when i connect it the TB and ecu doesn't even react. like its not even hooked up. however that could be a dead or bad pedal as i never verified myself it to be operational, however the APP sensors in it react and sweep through the ohms to be what ive found to be accurate, but definitely not 100% on that one either to be honest.

TAC module part number is 12590008 just looked up my ebay order here at work. have two of them identical units

2006 Trailblazer V8 uses a E40 with no separate TAC, completely different universe. You need a pedal from something designed to work with a P59/TAC.

From '06 Express Electronic Throttle 'Description and Operation':

Quote:

The accelerator pedal assembly contains 2 individual accelerator pedal position (APP) sensors within the assembly. The APP sensors 1 and 2 are potentiometer type sensors, each with the following circuits:
? A 5-volt reference circuit
? A low reference circuit
? A signal circuit

The APP sensors are used to determine the pedal angle. The control module provides each APP sensor a 5-volt reference circuit and a low reference circuit. The APP sensors then provide the control module with signal voltage proportional to pedal movement. Both APP sensor signal voltages are low at rest position and increase as the pedal is applied.

From '06 TB Electronic Throttle 'Description and Operation':

Quote:

The accelerator pedal contains 2 individual accelerator pedal position (APP) sensors within the assembly. The APP sensors 1 and 2 are potentiometer type sensors each with 3 circuits:
? A 5-volt reference circuit
? A low reference circuit
? A signal circuit

The APP sensors are used to determine the pedal angle. The engine control module (ECM) provides each APP sensor a 5-volt reference circuit and a low reference circuit. The APP sensors provide the ECM with signal voltage proportional to the pedal movement. The APP sensor 1 signal voltage at rest position is less than 1 volt and increases as the pedal is actuated. The APP sensor 2 signal voltage at rest position above 4 volts and decreases as the pedal is actuated.

2 Attachment(s)

As a Hail Mary, go to the APP connector and swap some wires around, A>C/C>A. That should reverse the output of APP2, may not be the correct value but it'll at least go the same direction as what the Express TAC is expecting.

Attachment 90816

Attachment 90817

blindquirrel, you are awesome sir, exact info i was needing. i did infact do the exact wiring swap you described about three weeks ago trying to daig this issue originally thinking my wiring was messed up. your post above that also explains why its hard to find a tac to pedal harness for a trailblazer...cause there isnt one lol. guess im hunting a truck TAC module, have a spare 05 tac harness and pedal, just need the TAC if everyone thinks that will work with my P59. buddies running a similiar setup in his colorado and he has all 04 yukon dbw parts on a P59, idk imagine 05 truck should be the same and cooperate with the OS fine...am i wrong in any of that gents? thanks a ton

also...possibly hail mary again....whats the odds of copying e40 throttle tables to my p59 tune and making the pedal assembly work? or is it the tac module reading the pedal thats the main issue. becuase it functions, just not on quick changes or above 40%. thats what made me think it was within the ecu variables/ranges to start with and post on here

You should look at 2004 Envoy/TB 5.3L parts & tune files, since that's the pedal you want to/have to use. '04 was P59 with a separate TAC module, and the same pedal mounting config.

BTW, '04 & '06 TB pedals have different part numbers but the same bolt pattern (different electrically inside, same outside).

EDIT: No, sorry! Same p/n.

TAC module #12588922 and a '04 5.3L Envoy/TB/Rainier/Bravada/whatever OS and you should be good to go (as long as your PCM is compatible). Go back and verify connectors are pinned to match GMT360 diagrams.

thanks again blindsquirrel, every search I've done today is showing 2004 envoy as E38 ecu. is there a specific part/model number you have for the tac model I'm in need of? because i have everything else if its P59 compatible. I also have a spare truck pedal and harness so i ordered a 2005 tac module as backup, model 12573059. so if i cant find a bolt in option...then a little fab, heat and weldin to the pedal will have to suffice. function is the main priority!

nvm, I'm an idiot...or coffee hasn't fully kicked in, i just now saw your most recent post showing model number....let the hunt continue lol

E38 was never used in any of the GMT360s. P59 for '03-04, E40 '05-06, E67 '07-09 when they went to 58x motors. Wherever you're getting that info from you should probably delete that bookmark.

and i now have a tac module model 12588922 enroute to me. ill try that one first after verifying harness pinout is proper. if that doesn't jive then well switch to the truck setup and see if the OS agrees with it. fingers crossed. thanks a ton blindsquirrel, even if this isn't a for sure fix it atleast offered me direction on things to check and try. i was getting to a dead spot with the info i had just yesterday.

also for record and future lookers....the pedal assembly i have is specifically part number 15145758

I can post '04 Trailblazer diagrams/pinouts if you need, don't want to clutter up everything if you already have them.

Yes if you don't mind, it'll help me verify tac to pedal harness is pinned properly for when the new tac arrives. Hopefully Monday or Tues

5 Attachment(s)

Code:

Powertrain Control Module (PCM) Connector C1 Pin Wire Color Circuit No. Function 1 BK 450 Ground 2 L-GN 1867 12-Volt Reference 3 PK/BK 1746 Fuel Injector 3 Control 4 L-GN/BK 1745 Fuel Injector 2 Control 5-6 -- -- Not Used 7 GY 705 5-Volt Reference 8 GY 597 5-Volt Reference 9-10 -- -- Not Used 11 L-BU 1876 Knock Sensor 2 Signal 12 D-BU/WH 1869 CKP Sensor Signal 13 OG/BK 463 Requested Torque Signal 14 OG/BK 1061 UART Serial Data 15 D-BU/WH 774 UART Serial Data 16 -- -- Not Used 17 D-BU 1225 Transmission Fluid Pressure Switch Signal B 18 RD 1226 Transmission Fluid Pressure Switch Signal C 19 PK 439 Ignition 1 Voltage 20 OG 440 Battery Positive Voltage 21 YE/BK 1868 Low Reference 22 -- -- Not Used 23 BK 2759 Low Reference 24 BK 450 Heater Ground - Heated Oxygen Sensor (HO2S) Bank 1 Sensor 1 25 TN 1671 HO2S Low Signal - Bank 2 Sensor 2 26 TN 1667 HO2S Low Signal - Bank 2 Sensor 1 27 BK 450 Heater Ground - Heated Oxygen Sensor (HO2S) Bank 1 Sensor 2 28 TN/WH 1669 HO2S Low Signal - Bank 1 Sensor 2 29 TN 1664 HO2S Low Signal - Bank 1 Sensor 1 30-31-- -- Not Used 32 BK/WH 771 Transmission Range Switch Signal A 33 PU 420 TCC Brake Switch/Cruise Control Release Signal 34 WH 776 Transmission Range Switch Signal P 35 -- -- Not Used 36 BK 1744 Fuel Injector 1 Control 37 YE/BK 846 Fuel Injector 6 Control 38 -- -- Not Used 39 YE/BK 625 Starter Enable Relay Control 40 BK 450 Ground 41 -- -- Not Used 42 WH/BK 2366 Cooling Fan Clutch Control 43 RD/BK 877 Fuel Injector 7 Control 44 L-BU/BK 844 Fuel Injector 4 Control 45 GY 2700 5-Volt Reference 46 GY 2709 5-Volt Reference 47 -- -- Not Used 48 GY 2704 5-Volt Reference 49-50-- -- Not Used 51 D-BU 496 Knock Sensor 1 Signal 52 -- -- Not Used 53 BK 2762 Low Reference 54 OG/BK 469 Low Reference 55-56-- -- Not Used 57 OG 440 Battery Positive Voltage 58 D-GN 1049 PCM Class 2 Serial Data 59 YE 710 Class 2 Serial Data 60 GY 2365 Low Reference 61 PK/BK 632 Low Reference 62 -- -- Not Used 63 BK 407 Low Reference 64 BK 450 Heater Ground - Heated Oxygen Sensor (HO2S) Bank 2 Sensor 1 65 PU 1670 HO2S High Signal - Bank 2 Sensor 2 66 PU 1666 HO2S High Signal - Bank 2 Sensor 1 67 BK 450 Heater Ground - Heated Oxygen Sensor (HO2S) Bank 2 Sensor 2 68 PU/WH 1668 HO2S High Signal - Bank 1 Sensor 2 69 PU/WH 1665 HO2S High Signal - Bank 1 Sensor 1 70-71-- -- Not Used 72 YE 772 Transmission Range Switch Signal B 73 BN/WH 633 CMP Sensor Signal 74 YE 410 ECT Sensor Signal 75 PK 1020 Ignition 0 Voltage 76 BK/WH 845 Fuel Injector 5 Control 77 D-BU/WH 878 Fuel Injector 8 Control 78 -- -- Not Used 79 WH 687 3-2 Shift Solenoid Valve Control 80 GY 720 Low Reference Powertrain Control Module (PCM) Connector C2 Pin Wire Color Circuit No. Function 1 BK 450 Ground 2 BN 418 TCC PWM Solenoid Valve Control 3-4 -- -- Not Used 5 TN/BK 464 Delivered Torque Signal 6 RD/BK 1228 PC Solenoid Valve High Control (Sol. A) 7 -- -- Not Used 8 L-BU/WH 1229 PC Solenoid Valve Low Control (Sol. A) 9 D-GN/WH 465 Fuel Pump Relay Control 10 WH 121 Engine Speed Signal 11-13-- -- Not Used 14 RD/BK 380 A/C Refrigerant Pressure Sensor Signal 15 RD 225 Generator Turn-On Signal 16 GY/BK 1694 4WD Low Signal 17-19-- -- Not Used 20 L-GN/BK 822 VSS Low Signal 21 PU/WH 821 VSS High Signal 22-24-- -- Not Used 25 TN 472 IAT Sensor Signal 26 PU 2121 IC 1 Control 27 RD 2127 IC 7 Control 28 L-BU/WH 2126 IC 6 Control 29 D-GN/WH 2124 IC 4 Control 30 D-BU 2364 Cooling Fan Speed Signal 31 YE 492 MAF Sensor Signal 32 L-GN 432 MAP Sensor Signal 33 -- -- Not Used 34 D-GN/WH 428 EVAP Canister Purge Solenoid Control 35-38-- -- Not Used 39 RD 631 12-Volt Reference 40 BK 450 Ground 41 -- -- Not Used 42 TN/BK 422 TCC Solenoid Valve Control 43 D-GN/WH 459 A/C Compressor Clutch Relay Control 44 -- -- Not Used 45 WH 1310 EVAP Canister Vent Solenoid Control 46 BN/WH 419 MIL Control 47 YE/BK 1223 2-3 Shift Solenoid Valve Control 48 L-GN 1222 1-2 Shift Solenoid Valve Control 49 YE/BK 1827 Vehicle Speed Signal 50 D-GN/WH 817 Vehicle Speed Signal 51 YE/BK 1227 TFT Sensor Signal 52 BN 2391 HO2S Heater Low Control - Bank 1 Sensor 2 53 RD/WH 3223 HO2S Heater Low Control - Bank 2 Sensor 2 54 PU 1589 Fuel Level Sensor Signal 55-56-- -- Not Used 57 BK 2760 Low Reference 58 TN/WH 332 Oil Pressure Sensor Signal 59 PU 806 Crank Voltage 60 BN 2129 Low Reference 61 BN/WH 2130 Low Reference 62 GY 773 Transmission Range Switch Signal C 63 PK 1224 Transmission Fluid Pressure Switch Signal A 64 D-GN 890 Fuel Tank Pressure Sensor Signal 65 -- -- Not Used 66 PU/WH 2128 IC 8 Control 67 RD/WH 2122 IC 2 Control 68 D-GN 2125 IC 5 Control 69 L-BU 2123 IC 3 Control 70-71-- -- Not Used 72 BK/WH 3113 HO2S Heater Low Control - Bank 1 Sensor 1 74 L-GN 3212 HO2S Heater Low Control - Bank 2 Sensor 1 75 GY 23 Generator Field Duty Cycle Signal 76-79-- -- Not Used 80 BK 2751 Low Reference