03 speedometer problem

[InsaneRedRooster]

So my speedometer started acting funny today. when I'm stopped the speedo will slowly fluctuate between 0 and 15mph, however when I gain any speed it will operate normally. The Tech library and sticky thread seem to have some conflicting information on this subject. Does the PCM get the vehicle speed from the ABS sensor on the diff. or the OSS sensor I see referenced but cant seem to find a picture or part number for?

I should also note I removed the gauge cluster recently to replace the gear indicator cable (This was over 1k miles ago now). And it was also very wet outside today and I enjoy going through puddles fast .

I would do more searching but it racks up miles slowly when I'm not moving. Pretty sure this is a question for adsm.

Thanks in advance .

EDIT:3.0 automatic

 

[adsm08]

Ok, according to the shop manual the PCM uses the OSS sensor, not the diff sensor.

Looking at the test that matches the symptom most closely (Speedometer inaccurate) the only two options are to put the correct sized tires on it or replace the speedometer. I really kinda don't like either of those answers. It's a gut thing.


I somewhat suspect a short in the sensor, but that is just a guess. I'd start by unplugging the sensor while this is happening. If it keeps going, it is not the sensor. If it stops, the sensor probably has an internal short.

Another quick test you can do, throw it in park while this is happening, see if that stops it.

 

[InsaneRedRooster]

Ok, so I just took a short trip to the grocery store (about 15 miles) and it failed to repeat the previously stated symptoms. I can say it WAS doing it while in park. I have a hard time believing after all the puddles I've gone through that the sensor temporarily messed up because it was wet . I'm willing to bet the problem is intermittent and will return.

Thanks for clearing up the sensor confusion, adsm. I'm sure if it starts acting up again I'll be able to track it down.