Speedometer going up while sitting still
lorilou
08-07-2010, 03:00 PM
Hey all! I have a '03 T&C that has started to give me problems as of late.
Dec '09 replaced alternator & battery
April '10 replaced ECM...wouldn't start...nothing...
July '10 replaced TCM...here's where my problem started. I would be at a redlight/stopsign and my speedometer would go up to around 40mph while I'm not moving. Then, as I was about to take off from the light/sign, it would try to stall. We took it to a mechanic, who had no clue, and then to the dealership, who replaced the TCM. I got it back around a week later, and it was shifting hard past 45mph and the speedometer would still go up a bit. So, I took it back to the dealership and they reset the TCM...everything was fine.
The next week, I went out and the van wouldn't start...would start with a jump, but as soon as we took off the cables, the milage lights would start flickering. So, we went and bought a new battery...seemed to do the trick. Well, today, the speedometer started reving a bit again (only to 20) and started shifting hard past 50mph. Any ideas? Does the TCM need to be reset, or is it an electrical issue? Thanks!
Dec '09 replaced alternator & battery
April '10 replaced ECM...wouldn't start...nothing...
July '10 replaced TCM...here's where my problem started. I would be at a redlight/stopsign and my speedometer would go up to around 40mph while I'm not moving. Then, as I was about to take off from the light/sign, it would try to stall. We took it to a mechanic, who had no clue, and then to the dealership, who replaced the TCM. I got it back around a week later, and it was shifting hard past 45mph and the speedometer would still go up a bit. So, I took it back to the dealership and they reset the TCM...everything was fine.
The next week, I went out and the van wouldn't start...would start with a jump, but as soon as we took off the cables, the milage lights would start flickering. So, we went and bought a new battery...seemed to do the trick. Well, today, the speedometer started reving a bit again (only to 20) and started shifting hard past 50mph. Any ideas? Does the TCM need to be reset, or is it an electrical issue? Thanks!
RIP
08-07-2010, 06:41 PM
You're having shift problems and a speedo that has a mind of it's own. That points to an output speed sensor. This sensor is the sending unit for the speedo and has a hand in controling shift scheduling. Assuming you have the 4 speed 41TE transmission it is located on the right front of the transmission. As I said, it points to it. I have a hunch with your TCM history you may have something else going on. When you say they "reset" the tranny could that mean they reprogrammed it? If not that may be another option.
Your short battery life is another concern. Computers need clean stable voltage to operate correctly. Make sure your battery connections are clean and tight. Check the alternator output with a multimeter at the battery posts. With the engine running you should see around 14 vdc. If all is well there you may have what's known as a parasitic battery drain. Just means something is drawing power when it shouldn't. To check for it disconnect the negative battery cable and let it sit for 20 minutes. Now connect an ammeter in series between the disconnected negative battery cable and the battery post. You shouldn't see more than around 50 milliampres. If it's higher start pulling fuses until the draw drops below 50. Whichever fuse causes the drop is the circuit with the draw. You then reinstall the fuse then disconnect components in that circuit until the draw drops below 50. The component that makes it drop is the culprit.
Your short battery life is another concern. Computers need clean stable voltage to operate correctly. Make sure your battery connections are clean and tight. Check the alternator output with a multimeter at the battery posts. With the engine running you should see around 14 vdc. If all is well there you may have what's known as a parasitic battery drain. Just means something is drawing power when it shouldn't. To check for it disconnect the negative battery cable and let it sit for 20 minutes. Now connect an ammeter in series between the disconnected negative battery cable and the battery post. You shouldn't see more than around 50 milliampres. If it's higher start pulling fuses until the draw drops below 50. Whichever fuse causes the drop is the circuit with the draw. You then reinstall the fuse then disconnect components in that circuit until the draw drops below 50. The component that makes it drop is the culprit.
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