Drive By Wire (DBW) to (DBC) Cable Throttle Conversion
This page explains the steps needed to switch from Drive by Wire to Cable Throttle control. Usually, using Drive by Wire is recommended unless you lack the necessary parts. By adjusting the programming, you can improve throttle response by removing torque management. If you insist on using CABLE throttle, this information applies specifically to Gen 3 truck engines from 2003 to 2007.
Drive by wire is a system that uses a separate module called a TAC module. This module is placed between the Gas Pedal and the Throttle Body. It communicates with the PCM (Powertrain Control Module) using two specific wires. All the wiring for the throttle body and gas pedal goes to the TAC module, except for the Power and Ground wires. Removing the Drive by Wire wiring is relatively simple since you just need to disconnect the two dedicated communication wires, which are Pin 14 and 15 of the BLUE PCM connector.
GM used a cable throttle body in their Express Vans with the 4.8/5.3/6.0L engines until 2005, as well as in the GTO in 2004. In order for the cable throttle to work, the PCM (Powertrain Control Module) needs to be able to control the idle air control (IAC) motor. This motor is simply a stepper motor that opens or closes a valve to control the flow of air into the engine. I have identified PCM models from 2003-2007 that support the required idle stepper motor for cable throttle control. If the PCM's number is off by one digit, it won't be compatible. Most pickup truck PCM's do not support drive by cable (DBC).
1999-2002 Serv. No. 09354896, 12200411 - All BLUE/RED connector PCM will work with either drive by wire, or drive by cable, the PCM simply needs programmed correctly.
2003: Serv. No. 12576106 with Hardware No. 12570558 - Most all 2003 trucks should have this PCM
2004: Serv. No. 12586243 with Hardware No. 12583659 - Mostly GTO and Express vans got this PCM, as well as Caddy CTS-V. MIGHT be in trucks.
2005-2006: Serv. No. 12589462 with Hardware No. 12589161 - I think you'll only find this in Express Vans. Maybe in some pickups.
2007: Serv. No. 12602801 with Hardware No. 12589161 - Found only in Express Vans (even if the VAN was DBW, it supports cable throttle)
GM PCM’s with IAC drivers (needed for “Drive by Cable”)
SERV. NO.- HWD NO. –
12200411 – xxxxxxxx – 2002 F-Body, Corvette, S10, IAC DRIVERS INSTALLED
09354896 – xxxxxxxx – IAC DRIVERS INSTALLED.
12576106 – 12570558 – 2003 G-VAN, LM7, IAC DRIVERS INSTALLED. ALSO, C-TRUCK LM7
12581565 - 12575502 - 2003 M/L Vans, S/T Trucks
12582605 – 12580786 – 2003 C-MPV, L59
12586242 – 12583660 – 2004 C/K-TRUCK, LM7
12586243 – 12583659 – 2004 GTO LS1, IAC DRIVERS INSTALLED
12589463 – 12589162 – 2005 C/K-TRUCK/MPV, LM7, LQ4
12589462 – 12589161 – 2005 G-VAN, LQ4, IAC DRIVERS INSTALLED
12589463 – 12589162 – 2006 C-PICKUP, LM7
12602802 – 12589162 – 2006 C-PICKUP, L59
12602801 – 12589161 – 2006 – 2007 Express, Drive by Wire, IAC DRIVERS INSTALLED
Green = IAC Driver Circuit Present
Red = IAC Driver Circuit NOT SUPPORTED
Also, a tip on finding these. Any 4.3L V6 Pickup or S10-S15 Blazer/Jimmy Astro/Safari will have the above computer and can be programmed for the V8 Gen 3 LS engine.
First, check if your PCM can support the numbers mentioned. If not, do a final check by removing the PCM cover using 4 torx screws. Look for the chip controlling the stepper motor. Check if there are pins sticking through the circuit board labeled "B67U1". You can refer to the provided pictures to understand better. Note that removing the circuit board is not necessary or recommended for this check. I have been using this information for a few years and it is reliable.
No chip installed. WILL NOT WORK WITH CABLE THROTTLE
No pins through circuit board. WILL NOT WORK WITH CABLE THROTTLE
Circled is the stepper motor driver, and an extra capaciter that is found in DBC able PCM's. WORKS WITH CABLE THROTTLE
Notice the pins from that chip stick through the circuit board. WORKS WITH CABLE THROTTLE
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 and location shown match 2003+ express vans that had mechanical drive by cable throttle 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 are opposite between oil pressure and tps. If you use the oil pressure plug 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. If you don't switch the black & gray, the TPS will work backwards. Finally move the Oil Pressure Signal wire (TAN/WHT) FROM GREEN 58 to GREEN pin 24.
Another note, the EXACT location the TPS gets its 5 VOLT REFERENCE from does not matter, it could come from pin 7 or 8. Same goes for the LOW REFERENCE, it could come from pin 60 or 63. What IS important is that the TPS has 5 VOLT REFERENCE and LOW REFERENCE at the correct locations at the sensor.
WIRE COLOR / SENSOR PIN LOCATION - DESCRIPTION - PCM PLUG / PIN LOCATION
Throttle Position Sensor (FACTOR PIN LOCATION FOR 2003+ DBC EXPRESS VAN)
PIN A or 1 - GRAY - 5 VOLT REFERENCE - BLUE PIN 8
PIN B or 2 - BLACK - LOW REFERENCE - BLUE PIN 60
PIN C or 3 - DK BLUE - TP SIGNAL - GREEN 24
Oil Pressure Sensor (2003+ harnesses)
PIN A or 1 - BLACK LOW REFERENCE - BLUE PIN 63
PIN B or 2 - GRAY - 5 VOLT REFERENCE - BLUE PIN 7
PIN C or 3 - TAN/WHT - OIL PRESSURE SIGNAL - GREEN PIN 58
WIRE - IAC PIN # -DESCRIPTION - PCM PLUG - PIN LOCATION
Idle Air Controller Valve
LT GRN/BLK PIN - (A) - IAC COIL B LOW - GREEN PIN 77
LT GRN/WHT PIN - (B) - IAC COIL B HIGH - GREEN PIN 76
LT BLU/BLK PIN - (C) - IAC COIL A LOW - GREEN PIN 78
LT BLU/WHT PIN - (D) - IAC COIL A HIGH - GREEN PIN 79
If converting from DBW to DBC on a RED/BLUE harness, you only have to add the wiring for the IAC valve and TPS. Use this schematic for pin information.
If you have a RED/BLUE connector PCM, you CAN use this pcm on a 03+ harness (GREEN/BLUE connector) with cable throttle, with a few simple modifications. The only thing that needs changed, other than what was talked about above, is some of the oxygen sensor wiring. On the 2003+ blue/green connector PCM's, the PCM supplies a GROUND for the oxygen sensor heaters, and 12v+ comes from the fuse block. In the 99-02, power and ground is fed directly to the o2 sensor heaters. To make the changes needed to 2003+ blue/green harness, to work with a blue/red computer is this:
REMOVE: BLUE PCM connector pins: 24, 27, 64, 67. These should all be black with white stripes. These were extra ground wires provided to the 03+ pcm so it could control ground to the o2 heaters. The 99-02 pcm does not need these. Just pull the pins out, don't cut anything yet, we need to hook these to a few other wires we pull out of the PCM connectors.
Next, we need to remove the wires from the PCM connector that go to the oxygen sensor heater control. There are 4 wires, one for each oxygen sensor. If you are only using front oxygen sensors in you conversion, omit anything to do with Sensor 2.
Bank 1 Sensor 1 - BLACK/WHITE - GREEN connector pin 72
Bank 1 Sensor 2 - BROWN - GREEN connector pin 52 - after CAT o2 sensor
Bank 2 Sensor 1 - LT GREEN - GREEN connector pin 74
Bank 2 Sensor 2 - RED/WHITE - GREEN connector pin 53 - after CAT o2 sensor
Now, you should have 4 ground wires, and 2 (or 4) oxygen sensor heater control wires pulled from the PCM connectors.
You need to locate the 4 tan oxygen sensor low reference wires going into the BLUE pcm connector. If just using front o2 sensors, its BLUE pins 26 and 29. If also using rear o2 sensors, add pins 25 and 28. These wires will always be TAN and may have a white stripe. The easiest way I can think of to splice into these, is pull the pin out (REMEMBER WHERE IT GOES BACK) remove some insulation with a knife, solider on a wire, and slip some heat shrink up and past the terminal and shrink the heat shrink down over the splice. Then reinstall the pin in its original location. Leave about 12" of wire loose for each wire you splice into. Do this for all the o2 sensors you will be using.
So, at this point. You should have 4 black/white ground wires loose. 2 to 4 oxygen sensor heater control wires loose, and 2 to 4 wires going to each of the TAN wires. All of these wires need hooked together in a big splice pack. First get some larger heat shrink, 1/4 or 5/16 should work. Put about 4-inch-long piece of heat shrink over all 4 ground wires. Next strip off about 1-2 inches of insulation off all your wires. Start hooking them together end to end, you should be able to solider all these together, and slip the heat shrink over when done.
The last step is to make the connectors fit inside the PCM. This will require cutting the rib off the GREEN plastic terminal cover, so it will fit in the RED pcm socket.
You will need to use oxygen sensors for a 2002 chevy truck, 5.3L, will be a white plastic connector, and will plug right into the 03+ harness without changing plugs.