ECU / PCM

[Holey76 - Square Nut]

Sorry if this has already been posted, but the controls on my ck5 menu are not responding, so i cant6search.
I'm trying to locate the ecu & tcu on a 99 silverado 5.3.
I've removed the computer next to the battery (drivers side front)
?? tcu ?? That Looks like this

 

[imiceman44]

Sorry if this has already been posted, but the controls on my ck5 menu are not responding, so i cant6search.
I'm trying to locate the ecu & tcu on a 99 silverado 5.3.
I've removed the computer next to the battery (drivers side front)
?? tcu ?? That Looks like this

View attachment 509878

I thought the 5.3 started in 2000

 

[Holey76 - Square Nut]

I thought the 5.3 started in 2000

This is a late 99, but ya, everything I've seen insists its a 5.7, but it was my truck from 99 till 2016, and it's definitely a 5.3 with 4L60e.
Go figure.

 

[Fastereddie]

The 4l60e doesnt have a seperate tcm. Its ran by the ecm you already pulled.

 

[Blue85]

AFAIK, when the 5.3L came out, it used the PCM (Powertrain Control Module) you show there to do both jobs.

 

[imiceman44]

This is a late 99, but ya, everything I've seen insists its a 5.7, but it was my truck from 99 till 2016, and it's definitely a 5.3 with 4L60e.
Go figure.

So this is a first year, production of late 99 slated for registration in 2000.
I see a few here for sale and I always wonder.
I also see the gmt400 trucks listed as 2000 when technically they ended production in 1999 but some got sold late and registered as 2000.
So your truck is a gmt800 correct?

 

[Holey76 - Square Nut]

The 4l60e doesnt have a seperate tcm. Its ran by the ecm you already pulled.

Thank you.
I asked the giggle AI and it said they were separate, i had a feeling it was full of bs.

 

[Holey76 - Square Nut]

So this is a first year, production of late 99 slated for registration in 2000.
I see a few here for sale and I always wonder.
I also see the gmt400 trucks listed as 2000 when technically they ended production in 1999 but some got sold late and registered as 2000.
So your truck is a gmt800 correct?

I believe it IS the gmt800.
How can you tell ?

 

[imiceman44]

I believe it IS the gmt800.
How can you tell ?

Rounded fenders versus the more squarish gmt400

 

[Holey76 - Square Nut]

Rounded fenders versus the more squarish gmt400

Definitely the rounder fenders, looks like this

 

[Blue85]

My brother had a 2000 Suburban which was a GMT800 with a 5.7L.

 

[b454rat]

Pics or didnt happen. Never heard or seen a GMT400 with an factory LS, nor a GMT800 with an older engine. I have 2 2000 trucks both are GMT400s. IIRC there wasn't any heavy duty GMT800s in 99/00, why you could get a GMT400. With the Suburbans n Tahoes/Yukons, my guess is they were using up leftover parts.

 

[Holey76 - Square Nut]

My brother had a 2000 Suburban which was a GMT800 with a 5.7L.

A buddy of mine had a 2000 Tahoe that was gmt800/5.7. i have no idea what is or isn't / was or wasn't produced by GM, but I'm guessing another member may know.

 

[b454rat]

I have a 2000 Tahoe but is GMT-400. They did make both that year just like the heavier trucks. But never heard of one having an LS or an L31/Gmt-800

 

[Holey76 - Square Nut]

Ok, so my next question is for those who use HP tuners.
What hardware is a must, to tune my oem ecu ? (Mentioned earlier in the 1999 silverado LS) And is it worth buying or better to pay a seasoned tuner to set it up ?

 

[6872xtc]

Ok, so my next question is for those who use HP tuners.
What hardware is a must, to tune my oem ecu ? (Mentioned earlier in the 1999 silverado LS) And is it worth buying or better to pay a seasoned tuner to set it up ?

I don't know the exact dollar amount or what he purchased, but my son has HP Tuners software and has the ability to turn off vehicle anti-theft, EGR and other things. Just have to purchase the "credits' to do each vehicle. He isn't well experienced with other aspects of tuning, but is looking into things. He may be able to help you.

Oh! And yes, the 1/2 tons went GMT800 in '99.

 

[Blue85]

If you're looking at once and done for a single vehicle, it may be cheaper to have a shop do the tune. They sometimes have bulk licenses that could cover all 99 Silverados, for example. At that point, you're paying for their time and expertise. Doing it yourself, for the first time, has a pretty good learning curve, and trying to tune on the street takes way longer than it does on a dyno.

On the other hand, owning the tool gives you the option to make changes whenever you want. For example, you may want to adjust shift points a few times before you're happy with it. Some day you may want to disable a pesky EVAP code or re-scale the way your fuel gauge reads.

There is also the hybrid situation where you own the tool, but send data to someone experienced to do most of the adjustments. Then you're still free to make tweaks later on or put it back to stock.

 

[Blue85]

What hardware is a must, to tune my OEM ECU?

Any of their hardware should work. Some newer ones have built-in logging and there's an option for an analog input, but if you won't have a wideband O2 sensor, that doesn't really matter. Plus, there are widebands that can interface directly with the PC and there's some old trick for routing the analog signal in as the EGR signal. I've never used the bluetooth option, I use a USB cable because I've experienced some data corruption over bluetooth before, which is something you don't want when flashing.

Of course, you need some kind of laptop or tablet. I'm sure it's spelled out on their website. I typically use a Windows tablet because it has a normal USB-A and I can still have it charging with the HP Tuners dongle hooked up.

What kind of "tuning" do you want to accomplish?

 

[Holey76 - Square Nut]

If you're looking at once and done for a single vehicle, it may be cheaper to have a shop do the tune. They sometimes have bulk licenses that could cover all 99 Silverados, for example. At that point, you're paying for their time and expertise. Doing it yourself, for the first time, has a pretty good learning curve, and trying to tune on the street takes way longer than it does on a dyno.

On the other hand, owning the tool gives you the option to make changes whenever you want. For example, you may want to adjust shift points a few times before you're happy with it. Some day you may want to disable a pesky EVAP code or re-scale the way your fuel gauge reads.

There is also the hybrid situation where you own the tool, but send data to someone experienced to do most of the adjustments. Then you're still free to make tweaks later on or put it back to stock.

All great points. Thank you.

 

[Holey76 - Square Nut]

Any of their hardware should work. Some newer ones have built-in logging and there's an option for an analog input, but if you won't have a wideband O2 sensor, that doesn't really matter. Plus, there are widebands that can interface directly with the PC and there's some old trick for routing the analog signal in as the EGR signal. I've never used the bluetooth option, I use a USB cable because I've experienced some data corruption over bluetooth before, which is something you don't want when flashing.

Of course, you need some kind of laptop or tablet. I'm sure it's spelled out on their website. I typically use a Windows tablet because it has a normal USB-A and I can still have it charging with the HP Tuners dongle hooked up.

What kind of "tuning" do you want to accomplish?

I'm not sure. I bought holdners low buck truck cam for my 5.3 and other guys are saying it will need tuning to run right.