Best diagnostic tool for reading trouble codes?

I recently got fed up with my local dealer her in upstate NY after years of letting them maintain our cars. We own a 2001 and a 2004 Prius. The 2001 is going strong at over 112,000. The dealer has performed all of the periodic maintenance on the car. The car seems to run fine, but several times has thrown the check engine light. The last time this occurred the dealer told me it threw a P3191 troble code and that the ECU and gas tank needed to be replaced at the cost of $3500. I was shocked and awed. This was the first time we have had a suggestion of any major repair with either car. I read the TSB that the technician was referencing, and it seemed to be a possibility. I decided to do some checking, and found this site. After reading several threads, I determined that the throttle body was sticking, leading to a delayed start. A $5 can of cleaner fixed the problem.

The 2001 has thrown check engine before. I checked all my service records, and found that it threw a P3191 several years ago when we were on a trip to NH. Took it in to a dealer there, and they determined that our dealer back home had overfilled the crankcase with the just completed oil change, and fouled the sensor. This lead to delayed start and the P3191.

I have been reluctant to go under the hood because of the warranty, and the synergy drive technology is an undiscovered country for me. I just changed the transaxle lube after reading helpful threads here. Although the service record says they changed it as required, they never charged for the type IV on any of my invoices. The magnet was covered in scuzz and the fluid had a parafin smell. I don't think they did the required service. The job was a snap with the online guidance here, and a quart hand pump I got from Westmarine (used to change lube on lower units of outboards). I am well beyond warranty on the 2001, so we will see how long the transaxle runs.

Does anyone have a recommendation for a scantool that will work equally well on the 2001 NHW11 and the 2004 NHW20? How about a source for repair and maintenance manuals for both cars? At this point, I am highly motivated to do all my own maintenance going forward.

 

<div class='quotetop'>QUOTE(jk450 @ Oct 19 2007, 08:57 PM) [snapback]527992[/snapback]</div>

<div class='quotetop'>QUOTE(efusco @ Oct 18 2007, 02:03 PM) [snapback]527378[/snapback]</div>

How does the Scangauge II compare to other options? Since it would read both the 2001 and the 2004, seems like a good way to go. But since it is designed to service all OBDII vehichles, does it have a lot of software support for the Prius? I saw one reader designed for the 2001-2003 models at www.ecrostech.com that permits reading the temp of the SG1, SG2, and the inverter coolant temp. Does the expanded software patch on the Scanguage II for the Prius allow it to report back on parameters from any sensor under the hood with the right setup?