does ignition switch cause transmission problems?

[yazan]

hi. 5 days ago i got stuck key in the lock cylinder with start position. so i removed the ignition switch to turn of the car.
and keep running the car with turnning the ignition switch by hand to run / off until i recive the new lock…
while driving home i got a trany shifting problem with some codes so i left the car until i found the key cyl.
is that related to the ignition switch and the key lock cylinder?

 

[Maverick6587]

What codes did you see?

The park/neutral safety switch could be in play. That should only affect starting the vehicle though. That switch is located on the transmission and I'm not sure if those wires connect to the ignition switch or go directly to the PCM.

 

[yazan]

sorry. the codes was p0740 p0785

 

[Maverick6587]

It looks like it's unlikely that the ignition switch and the transmission problems are related.

P0785 Shift/Timing Solenoid Malfunction/ 3-2 Shift Solenoid Circuit Electrical
Some potential causes of the P0785 code may include:

• Faulty shift solenoid
• Blocked internal transmission fluid passages
• Mechanical failures in the transmission
• Low transmission fluid
• Dirty transmission fluid
• Faulty TCM or PCM
• Open or shorted solenoid valve harness
• Poor electrical connection in the shift/timing solenoid valve circuit

P0740 Torque Converter Clutch Circuit Malfunction
Some potential causes of the P0740 code may include:

• A faulty torque converter clutch solenoid
• A damaged torque converter or clutch
• Incorrect transmission fluid level
• Skipping over transmission maintenance
• A restriction within the transmission
• Internal transmission damage
• A faulty powertrain control module or transmission module

 

[yazan]

that would be very bad news. its my known bad luck 🎲

 

[Mooseman]

When there is an actual issue with power to the tranny, it will throw more than 2 codes. Looks more like a localized issue with either the wiring, the connector or the solenoids inside. Not likely a mechanical issue with the tranny itself.

 

[yazan]

ok , i got today p0740 p1860 p0753 p0785
and i can confirm that its related to the ignition switch / key lock cylinder

 

[Mooseman]

So did you replace the ignition key cylinder and/or the switch?

 

[yazan]

the ignition switch still in shipping. the lock cylinder replaced with another part.. its for Tahoe. oem is not available in my area. dealer ask for 120$.. the tahoe part look similar but with some different . its working fine now. i see some amazon feedback confirm its working. before i bye it.


the trany problem happened before and after replacing the lock cylinder.
when it happen i just have to remove the switch and re-install it. and delete the codes.

 

[Villa]

the ignition switch still in shipping. the lock cylinder replaced with another part.. its for Tahoe. oem is not available in my area. dealer ask for 120$.. the tahoe part look similar but with some different . its working fine now. i see some amazon feedback confirm its working. before i bye it.


the trany problem happened before and after replacing the lock cylinder.
when it happen i just have to remove the switch and re-install it. and delete the codes.

Hi sorry to bother I know this was a while back. I am currently having same exact issues with my envoy. And would like to ask what did you end up doing to fix issues?

My key gets stuck and I use a screwdriver to hit the button inside to remove keys. Also have the same codes and my truck is sluggish. So was wondering if it needs to replace solenoids. Thanks in advance

 

[Mooseman]

the ignition switch still in shipping. the lock cylinder replaced with another part.. its for Tahoe. oem is not available in my area. dealer ask for 120$.. the tahoe part look similar but with some different . its working fine now. i see some amazon feedback confirm its working. before i bye it.

He replaced the ignition switch.

 

[Villa]

He replaced the ignition switch.

And this made all the DTC codes go away?

 

[Chickenhawk]

Best to start a new thread, with your symptoms and codes.

Have you load-tested your battery? Key stuck is usually a battery problem. These platforms are heavily dependant on a good battery.

 

[Mooseman]

Agreed. This needs it's own thread. Please start a new thread with all the symptoms you are getting. The thing about the key getting stuck is a new one for this problem.

 

[yazan]

Sorry for the late reply. Yes ...no more codes or tranny problems after replacing lock cyl and ignition switch.... .yes Its weird but that what happened.

 

[Drake314]

Sorry for the late reply. Yes ...no more codes or tranny problems after replacing lock cyl and ignition switch.... .yes Its weird but that what happened.

Having the exact same issues on my 03 Envoy XL, will be looking at replacing both ignition switch and lock cylinder, thanks!