AFM not working

[draper11]

Recently had my transmission rebuilt, works great. However, now my 4 cylinder mode doesn’t work when I cruise at low speed. Not necessarily a bad thing, but what factors could have impacted this?

The transmission was reflashed and I suppose it is still in learning mode also?

 

[Geotrash]

Recently had my transmission rebuilt, works great. However, now my 4 cylinder mode doesn’t work when I cruise at low speed. Not necessarily a bad thing, but what factors could have impacted this?

The transmission was reflashed and I suppose it is still in learning mode also?

They may have flashed the ECM as well to tune out AFM because it's super hard 0n the lockup clutch in the TC when it's constantly engaging and disengaging. If so, I'd consider it a free gift.

 

[draper11]

I don’t think they did per my conversation with shop- wouldn’t complain- should I worry about a stuck lifter situation now?

 

[draper11]

Tahoe stuck lifter

I don’t think they did per my conversation with shop- wouldn’t complain- should I worry about a stuck lifter situation now?

forgot to mention- he did replace the rear main seal while he was in there. I am wondering if I lost a little oil and now have oil pressure just below op range needed for AFM but not low enough for oil
Pressure warning?

 

[Geotrash]

Tahoe stuck lifter

forgot to mention- he did replace the rear main seal while he was in there. I am wondering if I lost a little oil and now have oil pressure just below op range needed for AFM but not low enough for oil
Pressure warning?

Rear main seal change won't affect oil pressure at all. And unless you're down 3-4 quarts, oil level won't impact oil pressure either. What are your pressures sitting at now? Cold idle/highway/warm idle?

No reason to worry any more about a stuck lifter now than before.

 

[petethepug]

Unfortunately you’ve gotta follow up with the shop. If you don’t address this, you also won’t be able to fix any other unknown or unseen issues.

Just handle it as a follow up visit but make sure you get Ppwk on it or it’s like you never mentioned it or were there. Consider an Autosync for the truck to monitor / clear all the DTC codes through the dash display. Babys got a new pair of shoes so instant access to DTC’s without diagnostic equipment is key.

 

[Doubeleive]

you will be in relearn mode for about 50 miles or so.
take it out on the freeway and get up to about 60mph on the money level ground and light on the pedal and let it just sit at 60, you should see v4 mode eventually, it will go away if you push the pedal any noticeable amount

 

[draper11]

you will be in relearn mode for about 50 miles or so.
take it out on the freeway and get up to about 60mph on the money level ground and light on the pedal and let it just sit at 60, you should see v4 mode eventually, it will go away if you push the pedal any noticeable amount

So I hadn’t been able to get it in 4 mode, until just now… coasting at 60mph, it wouldn’t come on. However, if I briefly feathered the gas while coasting it would come on until additional pedal was applied.

I think the low pressure might be an issue. If the first hash is 20psi, it isn’t going much beyond that. It looks like AFM takes 26 to engage?

I ran a blue reader and only issue I had was an 02-sensor potentially going bad.

 

[draper11]

So I hadn’t been able to get it in 4 mode, until just now… coasting at 60mph, it wouldn’t come on. However, if I briefly feathered the gas while coasting it would come on until additional pedal was applied.

I think the low pressure might be an issue. If the first hash is 20psi, it isn’t going much beyond that. It looks like AFM takes 26 to engage?

I ran a blue reader and only issue I had was an 02-sensor potentially going bad.

Following up- bad at reading the dipstick with this relatively clean oil I guess. Drained the pan and I was around 4.5 quarts (outside of the quart of flush I ran). Pressure was back up from 20 up near 30 range at idle and 38-40 at speed, plus afm engaged as expected.

 

[Geotrash]

Following up- bad at reading the dipstick with this relatively clean oil I guess. Drained the pan and I was around 4.5 quarts (outside of the quart of flush I ran). Pressure was back up from 20 up near 30 range at idle and 38-40 at speed, plus afm engaged as expected.

Good news. Thanks for following up.