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My girlfriends 1998 chrysler cirrus is having some issues. At first the check engine light came on and the speedometer would start shaking back and forth while driving at constant speeds. We checked a few things and didn’t know what was wrong. Shortly after this the car won’t shift into 3rd gear and seems to stay in 2nd gear. You try to go 40mph and the car runs at 3000 to 4000 rpm’s. I changed the oil tonight but will be going to the parts store tomorrow to try some thing.
Does anyone have any experience with this type of problem?
Thanks
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I’ll offer a theory:
I’ll venture to guess that your transmission is mechanically fine. There is probably nothing wrong with your transmission whatsoever.
If I had to guess, you have a defective speed sensor and/or other fault in the speed sensor circuit, or the sensor gap is out of spec. Your transmission depends a lot on various inputs; one major input the transmission depends on is speed information. Since the transmission is receiving incorrect input, you are experiencing incorrect output.
*PULL THE CODES THAT CAUSED THE CHECK ENGINE LIGHT.. WHAT ARE THEY?
(do you have a P0501?) :dry:*Proper diagnostics using scan tools and electrical testing should verify (or discount) my theory and isolate the specific cause(s) of the problem.
Here is a wikipedia on the “Transmission Control Unit;” it will show you all the various inputs and outputs that influence your transmission performance. You will see that among the various inputs that vehicle speed is one of them:
Thanks so much for the help. That is the same thing I have been reading online.
My brother couldn’t find his code reader so I unpluged the battery to reset things and the same problems happened on my drive home. I’m going to head to autozone in the morning to have them read the code.
Aure the speed sensors hard to get to? Do I need to replace both sensors or just the input one?
Thanks again for your time and I will try to get this fixed sunday.
Are the speed sensors hard to get to?
Typically, they are easy to get to. On some vehicles they are plugged to the outside of the transmission. Other vehicles, like pick-ups, have the speed sensor plugged into the side of differential.
Do I need to replace both sensors or just the input one?
You are probably referring to 2 sensors plugged out the outside of your transmission, one in the front and one in the back. The sensor in the front (closest to the engine) probably detects input shaft RPM and compares this data to the rear sensor RPM in efforts to detect an acceptable amount of transmission slippage. If trans is starting to slip more than usual, it will throw a check engine light. Of the two sensors, the one in the rear will actually be used to determine vehicle speed. This would probably be the sensor you are interested in. Ask the parts guy for a diagram of the location of the sensor for your vehicle.
Be sure to do your homework before blindly changes sensors or playing ‘musical parts’ and hoping that the problem goes away.
http://www.fixya.com/cars/t6283989-got_2000
Why does the solution 1 say its the output sensor is the one that causes this? I’m trying to figure out which one to replace but maybe I will have to do both of them.
the output sensor is the only sensor that can provide speed information as it detects RPM of the final drive.
Well I got the code read and it was a speed sensor error code. There were two other transmission codes but they were likely flagged because of the speed sensor. I didn’t write down the code so sorry about that.
I replaced the output speed sensor. It took some looking around but it was located behind the front driver side wheel well. The battery is down there too so once you take the wheel well cover off the sensor was literally right there. The input sensor was maybe 5 inches farther in but I didn’t even change it. So probably 15 minutes to find the sensor and 2 minutes to change it. Drove the car down the highway and everything fine now. I did reset the computer as well and no check engine light.
Thanks for all the help. It was much appreciated.
TyThere were two other transmission codes but they were likely flagged because of the speed sensor.
Outstanding. A lot of people would have normally freaked out when they would have seen those transmission codes… Good job of understanding the real issue and ignoring the irrelevant information. Also, good job on changing out only one sensor.
A little bit of homework paid off. 🙂
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