Accelerator Pedal Mode "Limited"

[Stepside66]

My LS swap is complete. 2013 6.2. Starts up and idles great. When I press the throttle pedal, nothing. The HS Scanner shows the pedal is moving, but the throttle body doesn't. I have ohm checked all the wires from the accelerator pedal to the ECM and from the ECM to the throttle body. all are at or under .2 ohms. Also checked all to ground and all were good. Verified 5v into the pedal and checked it to reference ground. New throttle pedal didn't help Also, electrically checked the throttle body with a multimeter and didn't see any issues. Any Help is greatly appreciated.

[5FDP]

A question or two here.

You say the engine is a 2013 6.2 but what 6.2? What did the engine and harness come from?

The computer you are using is from a 2008 Yukon with a 6.2 and this is where problems could start. The throttle pedal, throttle body and operating system on the computer should all match to make things work easy.

[Stepside66]

Thanks, The engine and accelerator pedal is out of a 2013 Cadillac Escalade. I was told the ECM was as well, but obviously not. It is a factory harness. All stock. I was able to buy a 2012 Escalade E38 ECM hoping that would fix the issue, but it didn't.

[Jon S.]

The 2012 Escalade E38 ECM programming was intended for use with a 6L80 automatic transmission. It looks like someone has attempted to make some very basic changes, to try and get this to work with a manual transmission.

This is likely the root cause of your throttle issues.

[Stepside66]

The 2012 Escalade E38 ECM programming was intended for use with a 6L80 automatic transmission. It looks like someone has attempted to make some very basic changes, to try and get this to work with a manual transmission.

This is likely the root cause of your throttle issues.

Thanks Jon S, yes, I have a T56 behind it. I?m brand new to the tuning world. I?ve been reading night and day to learn as much as possible. Any recommendations on where to start to get it out of limited mode?

[Jon S.]

Typically the most straight forward option is to use a calibration from a similar vehicle that was originally equipped with a manual transmission. However, no Gen 4 Truck was ever offered with a manual transmission - so there is no readily available base calibration.

Some of the parameters that need to be adjusted are available in HP Tuners - however, many are not.

The other issue you may face is that your 2012 E38 ECM is running an old OS (12647991) - many of these ECMs were updated by a GM dealer during service to the latest OS (12653249). The later OS is more user friendly with respect to being adjusted for use with a manual transmission.

[LS2Ttype]

Jon S knows his SH*%

[Stepside66]

Thanks Jon S. In your opinion, what are my best options? Dyno tune? Tune repository and work with that tune?

[Jon S.]

Most tuners (dyno shop or otherwise) generally expect that any vehicle that lands in their lap, already has a base calibration that is correctly configured for all of the components in use. They tend to spend most of their time dialing in the airflow.

You will likely require the services of a very knowledgeable conversion tuner - who has developed parameters outside of those available in HP Tuners (or any commercial tuning software) - to configure the base calibration to function correctly.

If you happen to get the APP (pedal) working, the next thing you will notice is that the ECM registers 158 MPH all of the time, and that the output to the Speedometer (gauge cluster) is not functional.

[Stepside66]

Thanks Jon S. I do appreciate your help. I was hoping to get some input from a ls swap tuner possibly on here for suggestions to do this without trailering the car to the dyno/tuner shop. I would like to think someone else has done this before (maybe not).

[Jon S.]

Plenty of people have put a manual transmission behind a Gen 4 (58x) LS engine. Most would have used Corvette ETC (Electronic Throttle Control) components - throttle body, APP (pedal), and ECM programming - to get everything to work correctly.

Using Truck components and ECM programming is much more difficult - only a handful of people on the planet that can actually program the ECM correctly - maintaining all diagnostic and safety features.

Be careful of the tuner that you choose. Many would disable the throttle control diagnostics and DTCs - to get things working (or partially working). This approach disables all safety features, and raises the issue of liability.

Also, it is doubtful that you will find a tuner that can address the issue of the ECM reporting 158 MPH all of the time, and the output to the Speedometer (gauge cluster) not functioning.

[LS2Ttype]

Plenty of people have put a manual transmission behind a Gen 4 (58x) LS engine. Most would have used Corvette ETC (Electronic Throttle Control) components - throttle body, APP (pedal), and ECM programming - to get everything to work correctly.

Using Truck components and ECM programming is much more difficult - only a handful of people on the planet that can actually program the ECM correctly - maintaining all diagnostic and safety features.

Be careful of the tuner that you choose. Many would disable the throttle control diagnostics and DTCs - to get things working (or partially working). This approach disables all safety features, and raises the issue of liability.

Also, it is doubtful that you will find a tuner that can address the issue of the ECM reporting 158 MPH all of the time, and the output to the Speedometer (gauge cluster) not functioning.

Sorry to Hijack ,

Jon would it be better or is there a advantage to switching over to all Corvette equipment for a 58X conversion? (APP~gas pedal, Throttle Body "silver blade" and a 2008 LS3 Corvette OS 12617631)
For example i have The Vette gas But everything else it "Truck" (Truck throttle body and 2008 Truck E38 + OS "12617631", in my case its cheaper and easier to just get the Truck gas pedal installed to match all the rest of the parts, But would there be a advantage to switching over to all Corvette components
Please let us know
and
Thank You for all your help

[Jon S.]

Sorry to Hijack ,

Jon would it be better or is there a advantage to switching over to all Corvette equipment for a 58X conversion? (APP~gas pedal, Throttle Body "silver blade" and a 2008 LS3 Corvette OS 12617631)
For example i have The Vette gas But everything else it "Truck" (Truck throttle body and 2008 Truck E38 + OS "12617631", in my case its cheaper and easier to just get the Truck gas pedal installed to match all the rest of the parts, But would there be a advantage to switching over to all Corvette components
Please let us know
and
Thank You for all your help

I responded in your thread ...

[Stepside66]

Plenty of people have put a manual transmission behind a Gen 4 (58x) LS engine. Most would have used Corvette ETC (Electronic Throttle Control) components - throttle body, APP (pedal), and ECM programming - to get everything to work correctly.

Using Truck components and ECM programming is much more difficult - only a handful of people on the planet that can actually program the ECM correctly - maintaining all diagnostic and safety features.

Be careful of the tuner that you choose. Many would disable the throttle control diagnostics and DTCs - to get things working (or partially working). This approach disables all safety features, and raises the issue of liability.

Also, it is doubtful that you will find a tuner that can address the issue of the ECM reporting 158 MPH all of the time, and the output to the Speedometer (gauge cluster) not functioning.

So, the easiest is to get a Corvette Throttle Body, Corvette Pedal and have the ECM programmed to a Corvette OS? Recommend keeping the intake or change it out as well?

[Jon S.]

So, the easiest is to get a Corvette Throttle Body, Corvette Pedal and have the ECM programmed to a Corvette OS? Recommend keeping the intake or change it out as well?

The easiest course of action is to use an E38 ECM programmed as an LS3 Corvette with a manual transmission. This necessitates using a Corvette APP (pedal) and throttle body. In 2009, Corvettes switched to a different throttle body ("gold blade") - these are generally less expensive than the earlier "silver blade" throttle body.

Once you have the APP and throttle body in hand, then source a correctly programmed E38 ECM.

For a "silver blade" Corvette throttle body, the E38 ECM should be programmed as a 2008 LS3 Corvette with a manual transmission. For a "gold blade" Corvette throttle body, the E38 ECM should be programmed as a 2009 LS3 Corvette with a manual transmission.

There is no need to change any other parts - for the purposes of getting the throttle working, or for getting the ECM to correctly report speed.

The above will afford the correct base programming for your project, that will allow you (or any tuner) to then conduct project specific in vehicle tuning - at minimum the Fuel Injector data, MAF Sensor calibration, and VVE Tables will need to be adjusted for the Truck engine.

[Stepside66]

Alright Jon S. I appreciate the help. I need to get the P2138 figured out as well. I?ll give an update once I make some progress.

[Stepside66]

VIOLA! Turns out, the new accelerator pedal connector I bought was wired exactly backwards. What I thought was "A-B-C-D-E-F" should have been wired as "F-E-D-C-B-A". I mistakenly assumed the wire colors were correctly pinned. After repinning the connector the pedal works perfectly and P2138 is GONE!

[SteelGreenStallion]

I love a story with a happy ending.

[Stepside66]

I love a story with a happy ending.

Thanks! Me too!