My Pac was having the engine surging at idle speed for the past 2 weeks or so. Also the headlights were flickering (thought is was my old eyes playing tricks on me). Today, the "alternator light" went on.

Alternator finally bit the dust after 250,000 miles. Replaced alternator (easy), now alternator is back charging and the surge has gone away. Suspect the headlight flickering is also gone away!

 

This was exactly my issue! I spent an hour freaking out about the cost of a new trans, and then luckily found this forum. I'm a broke (student) mid-20's female, so I would have been especially screwed if I took this to a shop to get diagnosed and got hit with a thousand dollar estimate or more.

I had the alternator tested at Advance and they told me it was putting out 14v and it was fine. They also pulled the check engine codes, which I've listed below.

P0731
P0732
P1790
P0700
P0720

I can't afford a new trans, so I decided to try a new alternator on the advice of this forum even though it tested fine. I just replaced it with a remanufactured part from PepBoys. The whole process took 30 minutes. The codes all cleared and the car is driving perfectly again. I am no longer having surging or Speedo issues while idling and there is no clunking when shifting into drive or reverse. The whining noise is also gone.

On a side note, I would highly recommend the serpentine belt tool. They offer free tool rental at PepBoys, so I picked it up there. I paid a $30 deposit, but I got it back when I returned the old alternator for the core charge. It made the job a breeze.

If anything else comes up I'll edit this, but it seems this worked like a charm to clear up my problems!

 

Travis, just signed here specifically to say thanks. Stumbled on this post completely by accident. Was seeing all the same warning signs as everyone else - speedo jumping and van lurching into 2nd and 3rd at complete stops, sometimes stalling. CEL got tripped and would intermittently not want to go into 3rd gear when driving. Pull over, shut off the engine, wait a few seconds, and crank it up again and problem would go away for a short bit. Took it to Autozone to have them pull the codes - bam, P0700 and P0720. Researching the codes led me here.

Took the van to Firestone this morning to run an alternator test - BOOM, bad alternator. It's being replaced as I type this.

 

Confirmed. New alternator. Driving of from Firestone and everything was perfect. Put the van (2003 T&C 3.3) in drive and speedo sat properly at zero and no lurching when starting. Drove off and changed gears smoothly, something I hadn't heard it do in a while. Got to the light. No crazy speedy or lurching when at light or any other intersections. I really can't thank you enough Travis - we were seriously weighing out replacing the van or potential transmission work.

 

I created an account solely to reply to this post.

I have a 2005 Pacifica with 125,000 miles that had the EXACT same issues. Was suddenly showing 20-30 mph on the speedometer in Reverse but stopped with foot on the brake. Car would jump coming to a slow full stop. I researched and this thread came up near the top and there was more than enough info to convince me I probably had a bad alternator.

Took the car to my very trusted mechanic and walked him through all the info in this thread. He tested the alternator and said results came back with no signs of alternator problems. &$*%#!! Got the dreaded 700 and 720 codes though. My guy recommended the sensor replacement. Me: Are you SURE it's not the alternator? He called me back about an hour later. Mechanic: "I bought the sensor but before I put it on, I just wanted to check the alternator one last time. I cranked the AC, turned on all the lights, and revved the engine. I checked the alternator again, and it was all over the place. You definitely have a bad alternator." Didn't put the sensor on, changed the alternator, and all the codes went away. Saved me a ton of misery and most likely a ton of money too. My mechanic is honest and cheap and worth his weight in gold, but without this post there wasn't much reason to do anything but blindly follow the codes. Thanks again!!!!

 

I have these codes showing up on my car any idea as to what they mean?


P codes are 0128, 0404, and 0700.

 

=TravisAz;53318]Just posting this to share incase someone else has the same problem.

"Symptoms: Speedo reads +mph when sitting in drive, reverse with foot on the brake - usually showed between 10 and 25mph on the speedometer. Car 'clunked' when shifting into reverse and would feel like it was pulling hard against the brakes with an elevated idle."

Travis, you hit it on the nose! I replaced my alternator with a new one from Autozone and the problem disappeared instantly. I reset the computer to clear all the bad codes from it. Also, the engine check light disappeared. I hope this is it for the check light also. I'll know for sure in about 100 miles of driving.

THANKS AGAIN!!!!!

 

We recently were having the same problem many of you had. We replaced both input and output speed sensors, still had the speed starting off at 20mph. This thread encouraged us to take it to the local O'Reilly's and have an electrical test done on the van. It registered some bad diodes. Went home, disconnected the alternator, speedo was at zero! Replaced the alternator, now running perfectly! Van has over 270K on it. Thanks so much for sharing your trial and error which saved us from more frustrations!!!

 

Well, on vacation in North Dakota (from Winnipeg) when my fiance took my car to run some errands at the local Target. We had all just been out for the better part of an hour driving with no problem what so ever. Well, she took the car after it had sat for maybe 10 minutes (in the 28C heat) and about 3 to 5 minutes into her trip, and as she was coming to a red light and stopped, the car jerked forward (at first she thought she had been hit from behind!!). This freaked her out! Then the speedo started to act like a tach!! It would go from 20 to 40 mph, then back to 20 at a dead stop! At the same time, the engine would rev between 1000 and 1500 RPM. Both would go away when accelerating. But it would also hard clunk into gear as she pulled away and again when coming to a stop (most of the time. She DID have the AC on, and I believe the headlights too... )

I took the car for a test drive when she came back, and all of what she described happened and more. The Check Engine Light came on for me and stayed lit while I took it for a test ride. This is a problem as we are supposed to head back home Monday afternoon. Of note, but I can't be sure, with the accessories off (i.e. no A/C, radio, or head lights, etc.), the issue wasn't as pronounced.

So, I pulled the code(s) using the ignition turning on and off 3 times and it produced a P0700. Checking that told me I had trany issues and needed a scan tool to pull the codes from the TCM. My plan was to pull the codes the next day.

So I went to O'Reilys and they pulled P0700, P0731 and P0720. I then cleared the codes and they have not returned. Of note, the car started and ran fine in the (cool) morning! In fact, it didn't start to "act up" until later that day, but NOT to the same degree as the day before! Mind you today the winds were VERY high and I was driving into it most of the time.

My car has 124,000Kms on it, and is an 05 touring model. After reading this thread, I was feeling a bit better about what could be the cause of the codes, and went back to have the Alternator tested. However, it tested "fine" (but NOT under any kind of a real load!).

I'm also wondering if there is also a correlation between heat (under the hood, engine, ambient, alternator heat build up, etc.) and a possibly "flaky" (original to the year) Alternator...

My gut is telling me to replace the alternator and I think I will do just that. I will report back later on how it went, but would appreciate feedback on what I have above.

THANKS!

 

OK, a quick update... and one that has me believing that the issue IS the Alterenator!!

I did a quick test. I started the car, and turned on the headlights, driving lights, AC, radio and even the rear defrost.

Right way, the issue came up! The speedo did it's "trick" and the trany did a hard clunck when i went to drive away.

When I turned off everythng, the car acted as it should!!

So, I will be replacing the Alternator tomorrow!

Update to follow!!!