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dtc 39 and stalling

brokenmotor

brokenmotor

I don't know diesel
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Location
BC
I have fixed/cleaned/added grounds, cleared the codes, and it seems to run and drive ok except for the random stalling. I drove it for a few ten minute trips, and I would check codes each time, and just the 12 would come up. After it was fully warm, it started to randomly stall.As I slowed up for a light it stalled, as I was accelerating it stalled, cruising about 60 km/h it stalled as I backed off the accelerator. It will start back up immediately with no problem...only to stall soon afterwards. I checked the codes, and dtc 39 ' tcc stuck on ' shows up.
 
Brake light switch for DTC39, wiring\connections or\and FSD\PMD for stalling...................
 
gmctd said:
Brake light switch for DTC39, wiring\connections or\and FSD\PMD for stalling...................
Click to expand...

my brake lights work....or is that irrelevant to my problem?

Also, is it harmful to the transmission to drive with tcc stuck on?
 
Last edited:
brokenmotor said:
Also, is it harmful to the transmission to drive with tcc stuck on?
Click to expand...

The TCC can cause stalling if it is locked on. Usually in stop and go/ start and stop situations. You can cause damage to the trans input shaft with it stuck on as well. Especially if you are towing. The hollow input shaft can break.
 
Brakelight switch is also the TCC lockup switch............
 
TCC sticking 'on' will cause the engine to stall at slow speeds (same as coming to a complete stop in 1st gear with a stick shift).

Stalling could also be PMD related as jd points out....

Check all fuses.....send a PM to Acesnights1 - he has the 1995 service manual and can tell you what wires to probe for TCC troubleshooting....
 
dtc 39 is gone now.

I changed the brake switch, I have driven it a few times, no more dtc 39.

Now I get dtc 33 'egr control pressure/baro sensor circuit high'. If I clear codes and drive it, 33 comes back, and the truck sometimes stumbles.

What could be the cause of this code?
 
Also..there are three what I assume to be egr control solenoids mounted at the rear of the drivers side intake, with vacuum lines going to them. If I remove the vacuum line that goes to the firewall from those solenoids and then blow in the line while I am plugging the egr vacuum connection, air comes out of the back of the rearmost solenoid. I sprayed a soapy solution on there while I was doing this, and it definitely makes bubbles out of the back of it.

Is this contributing to my problem? Or is it normal? When I apply vacuum to the vacuum line, the solenoid leaks air in the same place
 
Sorry I didn't see this sooner to chime in. Yes I have the books but let me tell you a little story of the brake light switch. It is a multifunction switch so brake lights can work fine and it still be bad. What a MF to get that stupid clip off. My advice buy new clip, break old one.
 
brokenmotor said:
I will check the vacuum after I eat something....next time I start it.
Click to expand...

Pump is making 60cm or 24in vac. By the time it works its way through its circuit, it shows as 49cm or 20in.

I also discovered an intermittent broken wire right at the connector to the middle of the three solenoids. As I wiggled it, I could hear the solenoids stop working, and vacuum would drop to zero. I will now clear the codes and try driving it again.

My question about the third solenoid closest to the firewall still remains unclear to me. Is that leak that I can hear when I apply suction or pressure to the line a problem? I would think that they should be airtight, and is that where I am losing the 11cm or 4in of vac?

Also.... where do I go to find replacement connectors for those solenoids? I imagine that they are ALL just as brittle as the one that failed....

Thanks guys.
 
brokenmotor said:
I also discovered an intermittent broken wire right at the connector to the middle of the three solenoids. As I wiggled it, I could hear the solenoids stop working, and vacuum would drop to zero. I will now clear the codes and try driving it again.
Click to expand...
I have two trucks with 6.5 Both had same problem when I bought them. Don't know why they break there but it seemsas common as PMD Failure.
 
I ordered a new harness for those solenoids... it will be here in the morning. It is weird what it is doing...I get no codes...But I am getting a stumble/stall at light throttle application..but only after it is warm.
 
That wiring is often damaged during repetitious (sometimes careless) fuel filter r&r -
 
Acesneights1 said:
Get that FSD off the intake and under the truck. That might be part of your problem with stalling.
Click to expand...

Can I just lengthen my harness and move the FSD that I have? Any tips?

What gauge wire should be used? I am sure that I read somewhere on this site about a specific type of solder to use for the connections.

Thanks.
 
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