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Possibility of TCM Issues
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dms11t
New User
Mar 1, 2013, 6:39 AM
Post #1 of 3
(1683 views)
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Possibility of TCM Issues
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I own a 1999 Volvo S70 with 97,000 miles on it.
A light blinks which indicates an issue with my automatic gearbox and my speedometer and mileage counter go to zero. The car seems to be working in a higher gear, as it pulls slugishly foreward from a complete stop, while my rpms go up to the 2500s. Once it gets up to around 30 - 40 mph, it drives normally. This can happen from start, or at a stoplight after I have been driving for a while. It used to be rare, but now it is a frequent occurrence. Sometimes my ABS and Brake light will come on along with, or instead of the automatic gearbox warning. Sometimes the speedometer and mileage counter will go out without the gearbox issue, and visa versa.
This first happened ~5 months ago. It still works alright, except it has obviously killed my gas mileage. A recent development has raised my alarm yet again.
Now the car will seem to be stuck in a lower gear. Despite getting up to speed, the rpms indicate 2,500 at 30 mph. The engine sounds like it is working harder than the indicated rpms even. When I let my foot completely off the gas pedal, the rpms will stick at 2,500 for a few seconds and very slowly go down. It may remain at 1,500 until I hit the brake and it finally dips down to the idle 800 rpms.
I suspect the Transmission Control Module is wigging out, or maybe the sensors sending the info. I hope it is the sensors, for they may be cheaper. Which sensors specifically would be responsible for this? I have been informed of a malfunctioning front wheel sensor, but I doubt this one could throw everything out of whack. Could something else cause this altogether? The alternator due to the speedometer outage? The transmission itself?
Also the car has slowly taken on a significant vibration. It is most intense when the brake is applied and held at a complete stop. When put in park or accelerating, it decreases significantly. It is throughout the entire car though, not centralized anywhere that I can tell.
Any thoughts, recommendations, or tests I ought to do?
Advice is greatly appreciated.
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nickwarner
Veteran
/ Moderator
Mar 1, 2013, 5:15 PM
Post #2 of 3
(1649 views)
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Re: Possibility of TCM Issues
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First things first, get the codes pulled and post the code numbers here. There are far too many variables and we need to know what direction to take based off of code information.
What is the service history with his car? Even have any trans flush?
Your mention of a vibration even at a stop, while holding the brakes, makes me think you have a misfiring engine. A misfire can and will make the transmission reach poorly.
It all begins with the codes. You may have multiple issues going on here, especially with the loss of speed signal intermittently.
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dms11t
New User
Mar 3, 2013, 11:24 PM
Post #3 of 3
(1626 views)
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Re: Possibility of TCM Issues
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Thanks for the response!
When I head home next week I will pull the codes and post them. I don't have a diagnostic tool where I am now.
As for the service history, I only know of the past year after I bought the car off Craigslist. Other than tire related fixes, I've had to put on a missing upper engine mount, and replace all five spark plugs cause not all my cylinders were firing. After having it checked out in the past I have been told that my transmission fluid was a bit dirty.
Oh, and recently I have had a timing belt replaced, and fixed a coolant leak. Something wrong with the filter was causing the leak.
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