drive by wire to cable driven conversion
Thread Starter
Teching In
Joined: Nov 2013
Posts: 32
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From: lake wales FL.
drive by wire to cable driven conversion I'm at the point in my lq9/ls3 swap where it's time to modd the wire harness. The harness I have is drive by wire. But, I went with a fast intake and 102mm throttle body which is cable driven to avoid having to add a DBW petal. How do I change the wire harness to work with the cable throttle body?
That's easy.
Discard all wiring used for DBW, then install new wires for the TPS sensor and IAC motor. Existing wiring is of no use because it goes to TAC module.
TPS needs 3 wires and IAC 4, all of them go directly to the PCM.
If you are not comfortable with wiring, leave DBW harness alone just tape and hide it away, then install the new wires directly from the PCM.
When wiring is done you need to flash a tune from a vehicle which was DBC from factory. Not just the calibration, you need to overwrite all the PCM's memory with the DBC operating system, because the stock DBW tune will trip REP mode as soon as you start the engine.
A Express Van tune is often used for this purpose.
Your PCM must have IAC drivers installed in the motherboard, if it doesn't the IAC will not work and you'll have idle issues. Older PCMs are more likely to have IAC drivers. New PCMs don't have them.
Easy ain't it?
Discard all wiring used for DBW, then install new wires for the TPS sensor and IAC motor. Existing wiring is of no use because it goes to TAC module.
TPS needs 3 wires and IAC 4, all of them go directly to the PCM.
If you are not comfortable with wiring, leave DBW harness alone just tape and hide it away, then install the new wires directly from the PCM.
When wiring is done you need to flash a tune from a vehicle which was DBC from factory. Not just the calibration, you need to overwrite all the PCM's memory with the DBC operating system, because the stock DBW tune will trip REP mode as soon as you start the engine.
A Express Van tune is often used for this purpose.
Your PCM must have IAC drivers installed in the motherboard, if it doesn't the IAC will not work and you'll have idle issues. Older PCMs are more likely to have IAC drivers. New PCMs don't have them.
Easy ain't it?
Thread Starter
Teching In
Joined: Nov 2013
Posts: 32
Likes: 0
From: lake wales FL.
That's easy.
Discard all wiring used for DBW, then install new wires for the TPS sensor and IAC motor. Existing wiring is of no use because it goes to TAC module.
TPS needs 3 wires and IAC 4, all of them go directly to the PCM.
If you are not comfortable with wiring, leave DBW harness alone just tape and hide it away, then install the new wires directly from the PCM.
When wiring is done you need to flash a tune from a vehicle which was DBC from factory. Not just the calibration, you need to overwrite all the PCM's memory with the DBC operating system, because the stock DBW tune will trip REP mode as soon as you start the engine.
A Express Van tune is often used for this purpose.
Your PCM must have IAC drivers installed in the motherboard, if it doesn't the IAC will not work and you'll have idle issues. Older PCMs are more likely to have IAC drivers. New PCMs don't have them.
Easy ain't it?
Discard all wiring used for DBW, then install new wires for the TPS sensor and IAC motor. Existing wiring is of no use because it goes to TAC module.
TPS needs 3 wires and IAC 4, all of them go directly to the PCM.
If you are not comfortable with wiring, leave DBW harness alone just tape and hide it away, then install the new wires directly from the PCM.
When wiring is done you need to flash a tune from a vehicle which was DBC from factory. Not just the calibration, you need to overwrite all the PCM's memory with the DBC operating system, because the stock DBW tune will trip REP mode as soon as you start the engine.
A Express Van tune is often used for this purpose.
Your PCM must have IAC drivers installed in the motherboard, if it doesn't the IAC will not work and you'll have idle issues. Older PCMs are more likely to have IAC drivers. New PCMs don't have them.
Easy ain't it?
Easy NO! Doable maybe.
So let me get this straight... First I should get a PCM from a 2000 express van, then get a TPS and IAC sensors and wiring. Right? Will my 2005 2500hd Silverado wire harness plug into a 2000 express van PCM?
There are a couple options for you.
The 05 harness can be made to work with 99-06 PCMs. A 99-02 Fbody PCM has the proper OS to make your engine run good but it needs wiring rework.
A 03-04 PCM from a Express van works without wiring mods to the harness and has a good OS to start with.
First step is to get a PCM from a DBC car.
Then get the wiring diagrams for that vehicle to make the IAC/TPS wiring and check that everything else matches.
Then you need to tune it
The 05 harness can be made to work with 99-06 PCMs. A 99-02 Fbody PCM has the proper OS to make your engine run good but it needs wiring rework.
A 03-04 PCM from a Express van works without wiring mods to the harness and has a good OS to start with.
First step is to get a PCM from a DBC car.
Then get the wiring diagrams for that vehicle to make the IAC/TPS wiring and check that everything else matches.
Then you need to tune it
Teching In
Joined: Sep 2022
Posts: 31
Likes: 3
That's easy.
Discard all wiring used for DBW, then install new wires for the TPS sensor and IAC motor. Existing wiring is of no use because it goes to TAC module.
TPS needs 3 wires and IAC 4, all of them go directly to the PCM.
If you are not comfortable with wiring, leave DBW harness alone just tape and hide it away, then install the new wires directly from the PCM.
When wiring is done you need to flash a tune from a vehicle which was DBC from factory. Not just the calibration, you need to overwrite all the PCM's memory with the DBC operating system, because the stock DBW tune will trip REP mode as soon as you start the engine.
A Express Van tune is often used for this purpose.
Your PCM must have IAC drivers installed in the motherboard, if it doesn't the IAC will not work and you'll have idle issues. Older PCMs are more likely to have IAC drivers. New PCMs don't have them.
Easy ain't it?
Discard all wiring used for DBW, then install new wires for the TPS sensor and IAC motor. Existing wiring is of no use because it goes to TAC module.
TPS needs 3 wires and IAC 4, all of them go directly to the PCM.
If you are not comfortable with wiring, leave DBW harness alone just tape and hide it away, then install the new wires directly from the PCM.
When wiring is done you need to flash a tune from a vehicle which was DBC from factory. Not just the calibration, you need to overwrite all the PCM's memory with the DBC operating system, because the stock DBW tune will trip REP mode as soon as you start the engine.
A Express Van tune is often used for this purpose.
Your PCM must have IAC drivers installed in the motherboard, if it doesn't the IAC will not work and you'll have idle issues. Older PCMs are more likely to have IAC drivers. New PCMs don't have them.
Easy ain't it?
I'm in a similar situation, I have a 2010 ly6 with btr cam and a 4l70e transmission with a DBW harness and wanted to go DBC! I understand the 7 new wires forI AIC & TPS, just wondering if my PCM will be good to run this setup?
thanks!!
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Whatever reason you have for wanting to change to DBC is only a tiny inconvenience compared to what you would have to do to change it. None of the factory computers with IAC drivers will work with your 58x crank trigger. Any computer that you use would require an entirely different wiring harness. If you are interested in any BCM functions, you can toss the idea of any compatibility out the window.
Teching In
Joined: Sep 2022
Posts: 31
Likes: 3
Whatever reason you have for wanting to change to DBC is only a tiny inconvenience compared to what you would have to do to change it. None of the factory computers with IAC drivers will work with your 58x crank trigger. Any computer that you use would require an entirely different wiring harness. If you are interested in any BCM functions, you can toss the idea of any compatibility out the window.
Thanks again much obliged
Registered User
Joined: Jan 2025
Posts: 1
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I have a question lmao That's easy.
Discard all wiring used for DBW, then install new wires for the TPS sensor and IAC motor. Existing wiring is of no use because it goes to TAC module.
TPS needs 3 wires and IAC 4, all of them go directly to the PCM.
If you are not comfortable with wiring, leave DBW harness alone just tape and hide it away, then install the new wires directly from the PCM.
When wiring is done you need to flash a tune from a vehicle which was DBC from factory. Not just the calibration, you need to overwrite all the PCM's memory with the DBC operating system, because the stock DBW tune will trip REP mode as soon as you start the engine.
A Express Van tune is often used for this purpose.
Your PCM must have IAC drivers installed in the motherboard, if it doesn't the IAC will not work and you'll have idle issues. Older PCMs are more likely to have IAC drivers. New PCMs don't have them.
Easy ain't it?
Discard all wiring used for DBW, then install new wires for the TPS sensor and IAC motor. Existing wiring is of no use because it goes to TAC module.
TPS needs 3 wires and IAC 4, all of them go directly to the PCM.
If you are not comfortable with wiring, leave DBW harness alone just tape and hide it away, then install the new wires directly from the PCM.
When wiring is done you need to flash a tune from a vehicle which was DBC from factory. Not just the calibration, you need to overwrite all the PCM's memory with the DBC operating system, because the stock DBW tune will trip REP mode as soon as you start the engine.
A Express Van tune is often used for this purpose.
Your PCM must have IAC drivers installed in the motherboard, if it doesn't the IAC will not work and you'll have idle issues. Older PCMs are more likely to have IAC drivers. New PCMs don't have them.
Easy ain't it?
