DBW to DBC Conversion 03+ HarnessesWWW.LT1SWAP.COMVisit mypage for a lot of New Pictures & Harness Guideschannel for How Tovideos - E-Mail:This page is going to outline what is required when converting from a DriveBy Wire to Cable Throttle control. Most of the time I would see no reasonNOT using the drive by wire, unless you simply don't have all the parts.With programming, throttle response can be made better with the removal oftorque management. If you are dead set on CABLE throttle, then here yougo. The info covered on this page pertains to the Gen 3 truck engines, 2003 to2007 specifically.Drive by wire uses a separate module, called a TACmodule. This module goes in-between the Gas Pedal and the Throttle Body.The TAC module communicates with the PCM via two dedicated wires. Otherthen that, and Power/Ground, The throttle body wiring and gas pedal wiring ALLgo to the TAC module. So removing the Drive By Wire wiring is not toodifficult.
Pin 14,15 of the BLUE PCM connector are the two dedicatedcommunication wires.What makes things nice, is GM still used a Cable throttle body in the ExpressVans with the 4.8/5.3/6.0L engines until 2005 and the GTO in 2004. Toallow cable throttle, the PCM has to be able to control the IDLE AIR CONTROL (IAC)motor. This is simply a stepper motor.
DBW value in dBm is always 30 more because 1 watt is 1000 milliwatts, and ratio of 1000 (in power) is 30 dB, eg 10 dBm (10mW) is equal to -20 dBW (0.01 W). Input a value above, select the type of unit you wish to convert, and click the ‘Convert My Power’ button. All calculated values will be shown.
As the stepper motor turnsone way or another, it opens or closes a valve, and controls air flow into theengine. I have identified the PCM's 2003-2007 that WILL SUPPORT the idlestepper motor required for Cable Throttle Control. (MOST PICKUP TRUCKPCM's DO NOT SUPPORT DBC) If your number is 1 digit off, it won't work.1999-2002 Serv. 09354896, 12200411 - All BLUE/RED connector PCM will workwith either drive by wire, or drive by cable, the PCM simply needs programmedcorrectly.2003: Serv.
12576106 with Hwd. 12570558 - Most all 2003 trucks shouldhave this PCM2004: Serv. 12586243 with Hwd.
12583659 - Mostly GTO and Express vansgot this PCM, as well as Caddy CTS-V. MIGHT be in trucks.2005-2006: Serv. 12589462 with Hwd. 12589161 - I think you'll onlyfind this in Express Vans. Maybe in some pickups.2007: Serv. 12602801 with Hwd. 12589161 - Found only in ExpressVans (even if the VAN was DBW, it supports cable throttle)Also, a tip on finding these.
Any 4.3L V6 Pickup or S10-S10Blazer/Jimmy will have the above computer, and can be programmed for the V8 Gen3 LS engine.Okay. So there are some numbers to go off of. One final check tosee if your PCM can support it, if its not listed here. Remove the coverof the PCM (4 torx screws). What you are looking for is if the chip thatcontrols the stepper motor is there or not. Look for the pins stickingthrough the circuit board at the marking 'B67U1'. See pictures here:Removal of circuit board not required or recommended to check.
I only did thisto show you what is under those pins. The info above I've now used for a fewyears and is rock solid info.circled is the stepper motor driver, and an extra capaciter that is found in DBC able pcm's. WORKS WITH CABLE THROTTLEnotice the pins from that chip stick through the circuit board. WORKS WITH CABLE THROTTLEclose up of the pins. WORKS WITH CABLE THROTTLEno chip installed. WILL NOT WORK WITH CABLE THROTTLEno pins through circut board. WILL NOT WORK WITH CABLE THROTTLEclose up of no pins.
WILL NOT WORK WITH CABLE THROTTLEOnce you know you have the right PCM, I can program it for your application.You tell me the engine, trans, etc and I can fix you up. For those using4L60E trans, I use a base Pontiac GTO calibration, and make changes to matchyour configuration.
For those with a 4L80E trans, I use a base Express vancalibration.As for the wiring, you need to add wiring for the IAC motor and THROTTLEPOSITION SENSOR (TPS). You can use the 2003+ Oil Pressure sensor plug as a TPSplug, (computer does not need to know oil pressure) You will need to finda IAC plug. Almost any older GM vehicle will have this plug, check localparts yard or maybe a parts counter can get a replacement plug. Typicallythe IAC has two light green, and two light blue wires, one each with blackstripe and a white stripe.Here is a chart that will show the wire color, description,and where the wire needs to go in the PCM plugs.
The wire color andlocation shown match 2003+ express vans that had mechanical drive by cablethrottle bodies. You CAN use the oil pressure sensor plug from a 2003+harness for the throttle position sensor. Pay attention that the 5v ref and low ref areopposite between oil pressure and tps. If you use the oil pressureplug for tps, you need to do one or the other; switch the BLACK and GRAY wires at the TPS plug,or switch the BLACK and GRAY wires at the PCM.
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If you don't switch theblack & gray, the TPS will work backwards. Finally move the Oil Pressure Signalwire (TAN/WHT) FROM GREEN 58 to GREEN pin 24.Another note, the EXACT location the TPS gets its 5 VOLTREFERENCE from does not matter, it could come from pin 7 or 8. Same goesfor the LOW REFERENCE, it could come from pin 60 or 63.
What IS important isthat the TPS has 5 VOLT REFERENCE and LOW REFERENCE at the correct locations atthe sensor.