# Symptoms Of A Bad Transmission Control Solenoid



## How Do I

I was trying to find out what the symptoms of a bad transmission control solenoid are. I couldn't find a good explanation on the interwebs so thought maybe someone here could help??


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## agmantoo

http://freeasestudyguides.com/transmission-shift-solenoid.html


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## How Do I

A bad transmission solenoid wouldn't cause the check engine light to come on, right? So if it went bad the only way you would know is if you actually checked for a code and the computer kept it stored? Or if there was some other symptom(s) when these solenoids went bad...

Reason I ask is DW was getting ready to pull out this afternoon and when she put it in gear, the engine almost sounded like it was going to die. Then it did the seesaw rpms up and down until it leveled out. Real funny this Blazer keeps on doing all these neat tricks. Maybe I should lease it out to a circus.


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## InvalidID

How Do I said:


> A bad transmission solenoid wouldn't cause the check engine light to come on, right? So if it went bad the only way you would know is if you actually checked for a code and the computer kept it stored? Or if there was some other symptom(s) when these solenoids went bad...
> 
> Reason I ask is DW was getting ready to pull out this afternoon and when she put it in gear, the engine almost sounded like it was going to die. Then it did the seesaw rpms up and down until it leveled out. Real funny this Blazer keeps on doing all these neat tricks. Maybe I should lease it out to a circus.


 Sounds like the O2 sensor to me.


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## foxtrapper

A transmission solenoid can trigger a check engine code, depending on how the vehicle is rigged. If a transmission solenoid is failing, you will not engage that gear, or the overdrive, or the lockup, or 4wd, depending on what the solenoid is for in the transmission. 

From your symptoms, I'd say the CEL is on because of engine codes.


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## How Do I

InvalidID said:


> Sounds like the O2 sensor to me.


What makes you think that?


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## How Do I

foxtrapper said:


> A transmission solenoid can trigger a check engine code, depending on how the vehicle is rigged. If a transmission solenoid is failing, you will not engage that gear, or the overdrive, or the lockup, or 4wd, depending on what the solenoid is for in the transmission.
> 
> From your symptoms, I'd say the CEL is on because of engine codes.


The CEL isn't on. I just thought I'd read before that in older vehicles a transmission problem wouldn't trigger the CEL - reason I was asking. I found a web page where a guy said one of these solenoids sticking would cause the engine to almost die when moving the shift lever from park to drive because the transmission would be engaged already and that put enough strain on the engine to cause the loss in rpms. IDK how all that works.


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## foxtrapper

HDI, I didn't say the transmission solenoid will turn on the CEL, I said it can, depending on how the vehicle is rigged. You've never identified what this vehicle is, so I certainly can't say with certainty whether yours will turn on or not.

As well, like I said, there are various solenoids controlling various functions in the transmission. You can have different problems depending on which solenoid is failing. 

Trying to understand your vague description of the symptoms on this unidentified vehicle I inferred that the CEL was lit, and the engine was dying and surging. Which is why I suggested the problem would more likely be in the engine.

Better more detailed descriptions from you will help you get better internet diagnostic advice from people who are not there. All any of us have to work with is what you tell us.


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