check engine light is on - troubleshoot?

We really know the codes. However, I understand it may be possible to use a jumper between a couple of pins on the OBD connector to get them to read out. I've not done this but I've seen some reports.

Bob Wilson

 

It would be best to have the DTC read to understand what the problem is.

However, to offer a guess, since you've just had the inverter replaced 3K miles ago, is it possible that the inverter cooling system was not properly purged so that air is in the system - or else that the cooling pump has failed? You can check this yourself.

If you are interested, make the car IG-ON (where the instrument panel warning lights appear.) Open the hood and listen for the sound of the inverter cooling pump, located near the driver's side headlamp. It sounds like an aquarium pump and you should not hear air bubbles. The pump should be running at all times when the car is IG-ON or READY.

Also look at the inverter coolant reservoir. You should see that the fluid level at the very front is higher compared to the fluid in the remainder of the reservoir.

If you do not hear the pump running, then you know that is the problem. If you hear air in the system or you see that the fluid level is even across the reservoir, then you know that fluid is not pumping through the coolant loop.

 

I think there are scannerless, blinking-light options for reading out codes from the ECUs responsible for the engine, brakes, airbags, hvac, body electrical, and steering (have to supply your own blinkenlight for the steering). Most go into code-blink mode when you jumper TC to CG at the diagnostic connector (for the hvac, just tap A/C 3 times after turning ignition on, then turn the fan switch from off to auto).

However, the two most interesting ECUs for this thread, the HV and battery ECUs, do not have any alternate readout option that I can find in the manual, and will only talk to a scanner. Generic scanners other than THHT usually only know the LAN address of the engine ECU, so they don't see the others. The Ecrostech miniscanner knows the HV and battery ECU addresses and can retrieve several interesting parameters from them, but I've never had one and don't know if it can do diagnostic code retrieval also.

I've bought a programmable OBDII interface with the aim of seeing if I can get it to talk to these ECUs, but haven't had time even to get it talking to my laptop yet.

-Chap

 

I'm very interested in logging and/or retrieving obd2 data from my 2001 prius. What ISO standards does an interface need to support? Does it need to support CAN bus? Anybody have recommendations. I would most likely make one out of an arduino. Search Make dot com for the project. Any ideas?

 

Personally, I would spend $150 for a ScanGauge which does that or more. (Actually I already did that). If you want to get deep into the codes, talk to Dan. at greenhybrids.com (I think that's the right forum, he visits here too occasionally).

Isn't there a way to get the codes from "secret" menus on the MFD, or is that not available on the 2001?

 

CAN is not needed for the G1. I think 9141-2 and 14230-4 should be sufficient, but as I haven't had time to try to bring my interface up yet, I can't say that for sure.

The main hurdle is finding the address/parameter-ID/scaling/unit tables for the Prius-specific data. Some folks have reverse-engineered some of it (Graham Davies for the miniscanner, for example) but not completely or with complete confidence. A big step forward would probably be to create a wiki where the known table data can be published and added to as more is learned. It would also be helpful to configure an OBDII interface as a promiscuous listener, find somebody with an actual THHT, and watch some of the more interesting transactions (inf code retrieval, and some of the control actions like crank-for-compression, for example).

-Chap

 

I was in error before about the chat group with a forum on the Scangauge. It's actually at cleanmpg.com, check out the sticky on XGauge codes (raw OBDII codes as opposed to the canned ScanGauge codes).