$59 and Shift light... Other code masks might apply as well...

**Six_Shooter** · 07-02-2015

I've been trying to figure out how to get my shift light working per gear in my car, using $59.

So far I've only been able to get one RPM activation of the shift light regardless of gear using the "RPM over which shift light" setting that is an overall setting that ignores any specific gear ratio.

I've thought that the N/V ratios (RPM/MPH) might be off, but I've set them so wide at times that the car should think it's pretty much ALWAYS in first gear. lol

I've tried playing with the shift light on delay setting thinking it may be a delay for how long the light stays on, not a delay before it's activated, and no bueno.

I've set the TPS min really low, I'm going to try it really high because it may be an inverse thing, since I looked at a $58 bin from a Sunbird, that shows 99.71% (as high as the code allows), which I'm not sure if that's set so high to disable it, or if it's a disable TPS setting.

Now I'm curious at what point the ECM sees the vehicle speed, is it before or after the internal scaler adjustment? If it's before that might explain a little with the current drivetrain, since the VSS is something like 17000 pulses per mile, but I did have a 2000 PPM VSS in the car before using the same code, and couldn't get it to work then.

Any ideas?

Is there something I'm missing about the shift light function? Yes the manual trans flag is set.

I am attaching a grab of the parameters for the shift light, the rest of the gears are just repeats of the same, with different values, except 5th, but I don't care about a shift light in 5th...

**1project2many** · 07-02-2015

Let me think on this. Lotsa distractions at the shop right now.

I used the light on the Cavalier but only wanted RPM as a trigger. If you're trying to use load and RPM as GM did then it might take more work.

**Six_Shooter** · 07-03-2015

I'm only looking for RPM trigger per gear. Load doesn't seem to be a variable, unless I'm missing some defined items?

I really only need it to trigger at a lower RPM for first, and the rest of the gears can be the same RPM. Short shifting first always seems to get a better E.T. at the track, so I'd like to make that short shift as consistent as possible.

**1project2many** · 07-03-2015

Ok, my laptop doesn't want to start right now but I've looked through cals and notes on the desktop so I believe I can give enough in one post to get this working for you.

There is no load based value. GM used TPS hysteresis instead.
The "RPM Over Which..." must be lower than the desired activation RPM.
The gear specific Min TPS and Min RPM should be higher than the global minimums.
Keep minimum TPS values low to use a shift light as an RPM only light.

Constants from $58 2.2 Cavalier shift light attached. All table values are at zero.

**Six_Shooter** · 07-03-2015

I'm quite sure I tried setting the global RPM value lower than the gear specific value, but I may have had them set the same. I will have to make sure and re-test. I thought the same, that the "RPM over which light" might just be a value to enable the shift light to work, but the gear specific RPM values are then the "gate keeper" if you will.

I'll report back.

**1project2many** · 07-03-2015

If this doesn't work I'll either try to find any notes I kept last time I worked this out or I'll just sit with the code and work through it again. There was definitely something that was counterintuitive between the variable labels and the code.

**Six_Shooter** · 07-04-2015

Ok so I tested the idea of having the global rpm activation point lower than the gear activation rpm, and the global activation point is used regardless of gear settings.

I'm toying with the idea of going to $58 as a test and see if there was something changed in $59 or if that part of the code is different since I think they started with a Sy/Ty bin, though that shouldn't really matter.

**1project2many** · 07-04-2015

The code is the same, Syty or Sunbird. The shift light wasn't used in manual trans 'birds through so no quick and easy comparison available there.

I am sure the cavalier shift light activated at the higher values. The issue may be that I have later calibrations saved on the laptop with different values.

I'm going to have to work through the code and put the logic into a post on the internet. Then I'll be able to find it next time I need it.

**Six_Shooter** · 07-04-2015

I got looking at some more stuff last night, and remembered/re-discovered that there is a set shift light tables, that I would think how they are set would have no effect, but I couldn't find these same tables in any $58 XDF to compare.

**1project2many** · 07-05-2015

I'm still working through this. My kids are up so it's very tough to concentrate but I'd like to put a comprehensive description together. This little bit of code is convoluted.

Anyway, I knew something was tricky about this code but I was wrong about the trick. The global variable RPM Over Which Shift Light (Always On) overrides the gear specific tables as you found out. So you can set that to match the highest shift RPM desired and let it go. For a gear specific RPM limit set min RPM and min TPS as you'd expect. Min TPS should probably be a low number and min RPM should match the RPM where the light should turn on. The tables you found, TPS Thresh. For Shiftlight On, are also in $58 but the names are misleading. These tables provide an upper limit to the shift light enable window. Try filling the tables you found with 100% or as close as possible. Also, make sure all of the delay timer values are at zero. There are actually two timers just to complicate things. The global variables named minimum TPS and minimum RPM appear to be hysteresis values, not actual minimums. The gear specific minimum is used as expected: Until TPS or RPM equals or exceeds the minimum the light is not enabled. But once the light is on then the lower limit to shut the light back off becomes gear specific minimum - global hysteresis value. I'd set these global values to zero.

This is still incomplete and my suggestions are based on a couple of hours of working through the code while my kids are screaming and fighting in the background so they might not be 100% correct. I hope to have more time with this today to get a more complete picture of what's happening.

**ony** · 07-05-2015

this is probly a lot different the 7747 has a forced shift light setting witch I like my 288 seams to operate more off the map sensor. I don't know about adjusting what you are tring to adjust thought it might give you another idea where to look.

**Six_Shooter** · 07-06-2015

Thanks 1project2many, setting those tables, well I've only tested 1st gear so far, I figured if I can get one gear to work, I can get the rest to work... anyway, setting the values to 100% worked and now I have a shift light that comes on as set for 1st gear... finally... :D

I guess these tables are used to shut off the shift light, since in OEM use the shift light would have been for economy reasons and not performance reasons...

But why would they be a percentage and not just enable/disable values? Or is it like I've seen in some other code, anything above 50% is on, and anything below is off?

Guess that's one more thing to test.

**1project2many** · 07-06-2015

They're a percentage of TPS because GM didn't use load as a variable. Open throttle = higher load = don't upshift. The TPS table is actually baro compensated to make matters more complicated. I can't think of a reason offhand why load wouldn't work even with boost but that is how GM did it.