There are two flavors to controlling the throttle of your LS swap - cable or electronic. Depending on the year model, or generation of your engine, you may be able to pick and choose which better suits your desires or plans. 

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Generation 3

 

The Gen 3 series of LS/Vortec engines used a mixture of both cable and electronic throttle control, depending on the vehicle. These use a 24x crank reluctor wheel (discussed here in-depth) and engine control computer which can be programmed to accept both cable (DBC) and electronic (DBW) throttle control in many instances. 

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The DBC throttle system consists of 3 things - the cable drive accelerator pedal, compatible PCM (typically using red/blue PCM connectors), and a throttle body with two sensors - the Idle Air Control (IAC) and the Throttle Position Sensor (TPS). The DBW throttle system consists of 4 things - the electronic accelerator pedal, compatible PCM (typically using green/blue PCM connectors), TAC (Throttle Actuator Control) module and sub-harness, and throttle body.

 

If your engine was previously equipped with a DBC throttle system and you would like to use DBW throttle, you must ensure that the parts used are from the same vehicle to ensure compatibility and communication. Mismatched parts can lead to partial or no throttle response, reverse throttle movement, or other results. A largely overlooked item when converting from cable to electronic is the wiring harness and PCM. The engine harness PCM cover plates on DBW harnesses are typically green/blue, while DBC engine harness PCM cover plates are red/blue. Additionally, a DBC throttle engine harness will not have the connections for the electronic throttle body or the electronic accelerator pedal. All red/blue PCMs have the ability to control electronic throttle after correct programming.

 

Switching from DBW to DBC is very simple because there is not a concern with matching equipment and is typically desired when the DBW components are already not had. The primary concern when switching from DBW to DBC will be in the engine harness difference and the PCM difference. You will be required to add/modify your existing harness to include the IAC and TPS sensor plugs. Additionally, your DBW PCM may not be compatible with controlling a DBC throttle body and may require replacing it with a compatible unit. Below I will detail the DBW PCM's that are compatible with DBC. The service and hardware numbers must match or the appropriate driver for the IAC will not be present, and it will not work.

 

 

GM PCM's that have IAC drivers for DBC control

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Service Number - Hardware Number

12200411             – xxxxxxxx
09354896             – xxxxxxxx
12576106            – 12570558

12586243            – 12583659

12589462            – 12589161

12602801            – 12589161

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Generation 4 

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Generation 4 moved to a 58x reluctor wheel and a different engine computer. Using a factory ECM, there is not a provision or ability to read the sensors of a DBC setup, and as such, requires the use of a DBW throttle body. Additionally, components were upgraded and there is no longer a separate electronic accelerator pedal and TAC module. They have now been combined into one seamless item, the Accelerator Pedal Position. Use of a cable throttle on a Gen 4 engine paired with factory GM ECM can be accomplished in one of two ways - using a signal converter to step down to a simulated 24x signal, or actually use a 24x crankshaft and older style PCM and harness.