Transmission Problem 2005 Neon

[TC]

My 2005 Neon has been a great car. It has 215,000 miles. This is the problem. I was driving about 50 miles from my home to my sisters house. About halfway there the gauges started going crazy and all of the lights in the car ( including dome) started flashing. I figured that the car was just getting old so I didn’t pay it too much attention. When I got to my sister’s house, the car stalled while I was pulling into the driveway. Again, I didn’t pay it a whole lot of attention I just figured that the car is old. So, on the way home, the gauges were still going crazy. They would go from bottom to top and everywhere. Then the MIL light comes on. Then the car stalls again. So I pull over and start it back up just hoping to get home. It starts up fine and I continue driving. A mile or so later the RPM’s go through the roof and the transmission downshifted to what appeared to be first gear. As I was pulling over the car stalls again and wouldn’t start back up (at this point the MIL was flashing) so I had the car towed. The codes it has are U0155 twice ( Lost connection with instrument panel cluster) , P0700 (transmission control system [mulfunction indicator lamp request]) , and P0562 (system voltage low). When it stalled before I got it towed, I noticed that one of the headlights were dimmer than the other so I banged on it and it brightened up. I have no idea what this could be and could really use some advice because I really love this car and do not want to get rid of it. Thanks in advance for helping 🙂

Topic

[college man]

Address the p0562 first. check your battery and cables are clean
and tight. Take the car to an auto part store to have your battery
and alternator load tested for free. Once the charging system is fixed.
See if the other codes go come back after resetting them.

[TC]

I just replaced the battery a couple months ago. Do alternators have voltage regulators? And would low voltage actually cause the tranny to screw up? The reason I say is because I kinda thought I smelled something burning but I think it might have just been in my head. After the car sat for a while it started up and shifted fine but I never reset the codes.

[college man]

Usually now a days the voltage regulator is built into the
alternator. If the voltage is not correct the electronics
will not work right.

[Rick]

The voltage regulator in your car is built into the computer which cycles the alternator charging coil depending on system voltage, battery temperature and a few other variables.

Also, the transmission on your car, Chrysler’s 41te is a fully-electronic controlled transmission, so, yes, low voltage/battery/charging system problems can effect the transmission and is also likely to cause problems like you describe with the gauges and lights (that are also computer controlled.) So I agree with the above post that you should check your charging system first. One particularly subtle problem is that if one or more diodes in the alternator goes bad you can have good charging voltage, but an excessively “noisy” electrical signal. That can screw up a lot of things as the computers need clean DC voltage.

Don’t worry about the fact that the transmission seemed to go into first gear– that’s actually Chrysler’s “limp home mode” that the transmission defaults to whenever the computer can’t control the transmission. It allows the transmission to run manually in 2nd gear and reverse. The problem should clear automatically when you correct the likely electrical problem.

[TC]

Thanks so much for your help guys. I might tackle driving the car to the closest autozone which is 10 miles away tomorrow. The only thing that worries me is if the transmission goes into limp mode again and the car stalls and will not start back up, I’d be screwed because I don’t have the money to pay for another tow right now. But I do think I’ll get the alt tested. Hopefully fixing it is as simple as changing it. I will keep y’all posted.

[EricTheCarGuy]

System voltage is critical on modern vehicles. If you have an issue with system voltage every system on your vehicle will likely be effected. Based on your description, I would say that’s likely your problem. Even though you replaced the battery, it could still be an issue. It’s always the best place to start so load test the battery and confirm that it’s still good. Next, check system voltage. This article goes into more detail on how to do that.

http://www.ericthecarguy.com/faq/solving-automotive-electrical-problems

If you find a voltage problem, the next step is to narrow down where it’s coming from. We’ll get into that after you get your initial readings. Good luck and keep us posted.

[Author]

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