Behavior/symptoms + Several quick questions

Hi jeffkay,

Your symptoms seem similar to what I 've reported in this thread (last few posts).
http://priuschat.com/forums/international-owners/6539-prius-in-singapore-16.html#post1069605

1) Master Warning Light (Triangle), M.I.L (Check Engine Light) and Hybrid System Warning Light (red car with (!)) are on. Lower MPG due to ICE running all the time, no assist from HV Battery.

2) ICE not stopping even at traffic lights. Battery Fan running at full speed. After restart, Battery Fan back to normal speed. Recirculate Button not functioning, always at outside air.

3) ICE roars up then red dash brake light (Brake System Warning Light) comes on. Restart clears the BSWL.

You can find the location of the HV ECU here.
http://www.autoshop101.com/forms/Hybrid02.pdf

Suggest you obtain a subscription to techinfo.toyota.com.

Disconnect the Aux Battery or use OBDII scanner. But if the faults still present, the M.I.L. will come back again.

The 38 modules are monitored in 19 pairs of 2 modules each.

Which ECU? If you are referring to Key Transponder ECU, then yes.
Prius: 1st gen - Immobilizer / Lost all keys

An easier way is to use the THHT (Toyota Hand Held Tester) to check the voltages. The hard way is to dismantle the HV Battery.

 

Your car seems to have all of the classic symptoms of a bad HV battery, except that it is not showing that on the screen.

 

Have you checked the brake booster lines for leaks? The Prius has an auxiliary booster in case the main system fails. The boost comes from the engine, and that would explain the engine's need to shoot rpm's through the roof the generate boost. Check your brake fluid level too, as inadequate level can potentially cause this behaviour. Remeber to check the simple things first. I have learned from experience with my G1 that sometimes its the simple things that must be check first, before performing brain surgery! LOL!

Please keep us posted. I do not believe it is the HV battery, as your symptoms do not necessarily indicate that. When you checked the status of the 12V battery, I am going to make the assumption you checked it while the car is running because of the high voltage reading. This is not the correct method. To properly check the 12 V battery reading, you must leave the car stationary for about 20 minutes, then put the car in ACC, and check the battery using your display like you did. The reason for this is while the car is running, its going to be charging the 12V. I suspect that given the 13+ volt rating, that you have a failed 12V battery. G1 and G2 Prius' behave very strangely when the 12V battery runs low. It starts having all kinds of electronic gremlins. When my 12V died, the radio would make whiny noises, my "!" triangle illuminated, the A/C would work intermittently and the display would throw tons of errors at me. I replaced the 12V with and Exide Spiral Cell, and it works wonderfully. Please check these first before going through everything else.

 

Hi Jeff,

As Vincent recommended, you really should download repair manual info from techinfo.toyota.com so that you can be fully aware of the safety precautions associated with opening up the traction battery.

Responding to your question about the rear seat, there are two clips that hold the bottom cushion in place. Pull up hard on one side, to start the removal, then pull up on the other side. The rear cushion is held on with a few bolts visible after the bottom cushion is removed. Then the cushion can be slid up and removed. You'll also have to remove the trunk liner trim, to gain access to the traction battery.

DTC P3028 means that the voltage on that module pair is below standard. As soon as you measure voltages of each module it should become obvious which one is bad. The module pair will be near one end of the battery (don't remember how the numbering goes, from left to right or the reverse.)

A bad traction battery may either trigger the traction battery icon or the hybrid system warning icon in the MFD. In your case the latter appeared. That was also the case when my 2001 logged DTC P3006 (uneven module SOC) and the traction battery was replaced under warranty.

DTC P3009 means a high voltage leak. One possible reason among many would be a battery electrolyte leak to the case.

Good luck.

 

Hi Jeff,

When you measure the module voltages you'll probably find that one is noticeably low. It probably has a shorted cell.

It would be prudent to at minimum replace the failed module.

Some owners have replaced multiple modules surrounding the failed module under the theory that excess heat will have damaged the surrounding modules.

Since you are DIY I suppose you can replace just the one and then if you have a recurrence you'll know what to do. If you want to improve the likelihood of a permanent fix you might consider replacing all 38 modules with modules from a couple of 2G salvage traction battery assemblies as those are currently pretty inexpensive.

 

That was what happened in my case. However, I don't think it is voltage-wise, it should be resistance-wise. P3011-P3029 detect battery internal resistance as opposed to P3006 which measure difference in max. and min. voltage swing. Since P3006 didn't show up, that means no modules have more than 2V difference yet. So, I don't suggest to go and get a pair of known good modules at this point. After you have dismantled the battery case, you should isolate the Busbar first then measure each modules' voltage separately. If the voltage for module #35 & #36 are indeed lower than the rest, then start looking for good modules replacement. If all the modules are OK, then check the wire harness and the Battery ECU for resistance.

In my case, the KOH leaked onto the wire harness and connectors and cause resistance changes to the battery blocks. I had to cut several wires to bypass the connectors.

Good luck.

 

Yes, that is another way to troubleshoot.

There is a technical instructions for SSC-40G which I think will help you in dismantling the HV Battery.

toyota-prius-sat1 : toyota-prius-sat1

You need to register first then proceed to download this file:

Files/Service Campaigns/2001-2003 Prius/SSC 40G Details.pdf

 

I replaced the main battery in my 2001 Prius in Jan 2009 at 197000 miles with a new battery from Toyota. It took almost three weeks for the battery to arrive. In July 2010 the car began showing the symptoms described in this thread. I suspected the 12V battery that is nearing 3 years old. I had it replaced today with a new one but the car still exhibits the symptoms described in this thread with code P3011. The time it took to get the replacement hybrid battery and its failure so soon makes me think that the battery has had a long life in a warehouse.