[FIXED] 2001 GMC 3500 5.7L van stalling while driving no codes

This van will stall while driving then if shifted to neutral it will restart and be fine for a while then do it again. No codes. Any ideas? Security key maybe?


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Hard to say without some more direction.
We're going to have to figure out what goes missing when the van dies: fuel or spark.

At least with a van, you can pull the engine cover and do some testing.

I would start with a fuel pressure, just because I know there's a Schrader valve on the fuel rail and it's not a big deal to drive around the gauge hooked up on the van with the engine cover removed.

Got it to stall today on the way back to my shop. The last two miles it's a dirt road and a little rough, happened about 6 times. Now it has codes p0300, p0327, p0335, p0706, p1626 and p1870.
Feels like I shut the key off when it stalls while moving. Shift up to neutral and it starts back up with out stopping.
Thx Noah. I'll drive it tomorrow with a fuel gauge.


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Rory67 wrote: Got it to stall today on the way back to my shop. The last two miles it's a dirt road and a little rough, happened about 6 times. Now it has codes p0300, p0327, p0335, p0706, p1626 and p1870.
Feels like I shut the key off when it stalls while moving. Shift up to neutral and it starts back up with out stopping.
Thx Noah. I'll drive it tomorrow with a fuel gauge.


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Ok it looks like a bad Crank position sensor.
Got to go pick one up.
I think the p0706 transmission range switch code was from someone moving the shifter into reverse, hunting for neutral for a restart while the van was still moving.
The p1626 was probably caused by someone trying a restart before security light went out on the dash.
The P1870 "transmission component slipping" the PCM will set that if the van stalls while moving in gear with torque converter locked up, as it lost transmission pressure it would slip.

After clearing codes and getting it to stall again I only got 2 codes
The p0335 crank sensor, and a new code from the body control module. The infamous U1041 "loss of EBCM communication".

As usual this van has the scary looking corrosion around the PCM plug. Why would GM engineers think that it would be a good place for the pcm to be mounted? Under the brake booster and where the rain water runs down from the windshield right on top of it?


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Best PCM location ever!
I've re-pinned a couple of the van PCM connectors over the years. It's hard to not suspect a bad computer or pin fitment when you open the hood and the PCM case is swollen and cracked and the connectors look like the battery terminals of a neglected boat...

Hopefully the crank sensor is all it is, fingers crossed!

I just had a GMC van (2006 I think) with a 6.0 that kept throwing a P0300. The u joint was binding up pretty bad. Even with the u joint replaced it keeps trying p0300, random misfire, p0302 misfire #2, and p0306 misfire #6.
They changed plugs, wires and coils before asking me to check it out.
Crank variation relearn took less than a minute, I spent more time test driving it to make sure the light was cured than I did actually working on the van, lol!

After having no rpm signal on scan tool, I disconnected the blue PCM plug and checked the ckp sensor wires for shorts and opens all check out ok. So I put a crank sensor in it. Now I have a rpm signal on my scan tool.
When I try and start the engine it starts and runs for a second then dies. I had cleared the codes so when I check for codes again I get a P1626 "Theft deterrent Start enable signal not received"
The security lamp comes on when the key is turned to run position then goes off after a few seconds and remains off while cranking and when key is released to run position.
While cranking scan tool reads rpms as it starts and dies.



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Rory67 wrote: After having no rpm signal on scan tool, I disconnected the blue PCM plug and checked the ckp sensor wires for shorts and opens all check out ok. So I put a crank sensor in it. Now I have a rpm signal on my scan tool.
When I try and start the engine it starts and runs for a second then dies. I had cleared the codes so when I check for codes again I get a P1626 "Theft deterrent Start enable signal not received"
The security lamp comes on when the key is turned to run position then goes off after a few seconds and remains off while cranking and when key is released to run position.
While cranking scan tool reads rpms as it starts and dies.



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FIXED it, disconnected the battery ground and jumped from ground to positive with a test light for a few minutes and held the brake pedal for a bit to discharge PCM and BCM. Hooked it back up went and had a sandwich answered a few emails. Went out and it started up. Just got back from a 1 hour road test up and down my gravel road. I have a 3 mile rough road perfect for testing wiring problems to and from my shop/house.

Thx for the help


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Nice, good work!
Sorry I wasn't able to get back to this in a more timely fashion.

The start/stall is pretty typical for the GM security systems of that generation.
I'm surprised that disconnecting the PCM caused that. I would have suggested a 30 minute security relearn, but it looks like resetting the PCM did the trick.
I'll have to give that a shot in the next one I get before I try the relearn.
Again, nice work! Thanks for being patient!

Why does depressing the brake pedal help clear codes and memory?

GeekDIYMechanic wrote: Why does depressing the brake pedal help clear codes and memory?

Removes stored voltage in brake module, test light across the disconnected battery cables does same for pcm and security module. Some guys short the battery cables together I just don't like doing that.


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Ran great all day Monday then I see it back at my front door this morning customer said ran great back and forth to a job then developed a misfire on the way home.
So I start it up this mourning and it runs fine but has misfire code in the computer.
Clear codes run it up and down the driveway starts missing. Light a first then as it get good and heat soaked dead miss on number 5 cylinder. Pull plug wire on 5 no change in the way it misses. I have the doghouse off currently so it's easy to pull wires.
Ran a relative compression test and I get one low hump every eighth compression stroke. So I pull 5 and 7 plugs since there right next to my foot on the drivers side. Check compression and I have 130psi on 5 and 175psi on 7. Shot a couple squirts of oil on # 5 and the compression comes up about 7psi to 137psi.
Plugs look about the same burn wise swapping holes or wires makes no difference still missing on #5.
Let it cool off a couple of hours and the miss almost goes away but as it warms back up it slowly gets back to a dead miss.
Did an injector clean through the rail shader valve with fuel pump unplugged and return plugged off OTC 7448 tool.
No change after heating back up.
The miss gets bad enough to make engine light flash.




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Are you getting strong, consistent spark from the #5 wire when you disconnect it?

Those distributer caps are prone to cross firing.

Rory67 wrote: Ran great all day Monday then I see it back at my front door this morning customer said ran great back and forth to a job then developed a misfire on the way home.
So I start it up this mourning and it runs fine but has misfire code in the computer.
Clear codes run it up and down the driveway starts missing. Light a first then as it get good and heat soaked dead miss on number 5 cylinder. Pull plug wire on 5 no change in the way it misses. I have the doghouse off currently so it's easy to pull wires.
Ran a relative compression test and I get one low hump every eighth compression stroke. So I pull 5 and 7 plugs since there right next to my foot on the drivers side. Check compression and I have 130psi on 5 and 175psi on 7. Shot a couple squirts of oil on # 5 and the compression comes up about 7psi to 137psi.
Plugs look about the same burn wise swapping holes or wires makes no difference still missing on #5.
Let it cool off a couple of hours and the miss almost goes away but as it warms back up it slowly gets back to a dead miss.
Did an injector clean through the rail shader valve with fuel pump unplugged and return plugged off OTC 7448 tool.
No change after heating back up.
The miss gets bad enough to make engine light flash.

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Just ran a injector balance test with my Snap on modis 6 psi drop on all injectors until I get to #5 then it only drops like 3.5psi. LTFT B1 is at 25, B1S1 O2 135mv to 565mv lean B2S1 normal 200mv to 960mv LT fuel trim on B2 is 2 also reset the trims/learn goes back to the same in a few minutes of driving.
Cap looks good ran it in the dark no cross fire even after a water spray down test.
When I pull the wire off the cap nice hot spark jumps out to my test light for ground.
Call customer and told him it looks like a spider injector. He says he has another engine he would like me to pull the spider injector off it and replace this one with it. I told him to come get it and pay me for the diagnostics.


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Good work!
I love that injector balance test. Every car should support that feature.

Lmao while reading your description of codes." Someone " throwing it in reverse trying to hit neutral while rolling. Sounds like there should be a code for"better check the seat for stains before sitting"

LMAO!
I gotta check my couch now:oops: :whistle: :oops: