A Sick 2001 Prius

[gippah]

Hello McPostersons!

Anyhoo, with the arrival of 100-degree weather in central Texas, my Prius is not doing very well.

First, some background info:

- Over the past year or so the battery capacity hasn't been that great. If I floor the car for over 15 seconds or so, the battery charge goes down to 25% or 33% or whatever, from a fulll 66% or 75%.

- I got the red triangle last twice last winter during cold-morning starts. Both times it went away pretty quickly, I would merely pull it over and restart the car to force the ICE to try again. (Toyota dealership said the code was that the engine wouldn't start. They wanted to replace a relay, and I declined).

- The "Check Engine" light came on for awhile over the winter too. The dealership wanted to replace the catalytic converter for $2100. I declined. The light went away on its own.

- Fuel economy dropped, I could easily get over 50 MPG before, now I'm stuck in the mid-40s. This is probably slightly related to a change in driving habits, but not completely.

Now to the NEW stuff:

- I have noticed some hesitation in acceleration when first starting the car over the past few weeks. After a few minutes, acceleration returns to normal.

- About two weeks ago I saw the "Turtle" light for the first time. The battery had a good 2/3 or 3/4 charge. It was extremely hot/humid at this moment and the fan battery in the trunk was running at full tilt. The turtle light went off again after the temperature dropped a little. (Note that now I know what the turtle light really means. It doesn't mean drive slowly, it means that you won't be able to accelerate quickly, so don't even think about pulling in front of someone like you might do normally).

- This morning, the red triangle reappeared with some extremely noticeable problems with accelerating from a stop. It's almost like the brakes are stuck a bit, with a full throttle needed to release them. The engine comes on and runs. The A/C will run at its normal clip for awhile, then still blow cold air but at about half power. It is around 100 today with rather high humidity again. The battery fan in the trunk is again blowing noticeably.

Would anyone like to make a wager as to what's going on? Is my Prius on its last legs?

[bwilson4web]

Ask the service writer how much it would cost to get: (1) all codes read out, and (2) all battery assembly voltages and temperatures. If it is say $100, have them dump everything and then bring them back here. They also have a traction battery, internal resistance measurement procedure but that would probably cost extra for the technician time.

Bob Wilson

[Patrick Wong]

Originally Posted by gippah

Anyhoo, with the arrival of 100-degree weather in central Texas, my Prius is not doing very well.

First, some background info:

- Over the past year or so the battery capacity hasn't been that great. If I floor the car for over 15 seconds or so, the battery charge goes down to 25% or 33% or whatever, from a fulll 66% or 75%.

- I got the red triangle last twice last winter during cold-morning starts. Both times it went away pretty quickly, I would merely pull it over and restart the car to force the ICE to try again. (Toyota dealership said the code was that the engine wouldn't start. They wanted to replace a relay, and I declined).

- The "Check Engine" light came on for awhile over the winter too. The dealership wanted to replace the catalytic converter for $2100. I declined. The light went away on its own.

- Fuel economy dropped, I could easily get over 50 MPG before, now I'm stuck in the mid-40s. This is probably slightly related to a change in driving habits, but not completely.

Now to the NEW stuff:

- I have noticed some hesitation in acceleration when first starting the car over the past few weeks. After a few minutes, acceleration returns to normal.

- About two weeks ago I saw the "Turtle" light for the first time. The battery had a good 2/3 or 3/4 charge. It was extremely hot/humid at this moment and the fan battery in the trunk was running at full tilt. The turtle light went off again after the temperature dropped a little. (Note that now I know what the turtle light really means. It doesn't mean drive slowly, it means that you won't be able to accelerate quickly, so don't even think about pulling in front of someone like you might do normally).

- This morning, the red triangle reappeared with some extremely noticeable problems with accelerating from a stop. It's almost like the brakes are stuck a bit, with a full throttle needed to release them. The engine comes on and runs. The A/C will run at its normal clip for awhile, then still blow cold air but at about half power. It is around 100 today with rather high humidity again. The battery fan in the trunk is again blowing noticeably.

Would anyone like to make a wager as to what's going on? Is my Prius on its last legs?

It sounds like your car has several problems, and the best approach would be to have all DTC read so that you can see the full extent of the issues that you face. Lacking a list of diagnostic codes, following is my interpretation of your car's symptoms:

Usually the Classic SOC gauge will be at either 50% or 75%. Since you see it dropping down to 25%, this is evidence that the battery is weak. The turtle light may be further evidence to this effect; unless you had put the car under unusual load, like climbing a steep mountain road.

The cold weather starting problem is usually attributed to a downlevel engine ECU (the correct part number is 89661–47054) and sometimes to a bad circuit opening (aka fuel pump) relay or fuel tank (since the fuel pump is within the fuel tank.) TSB EG011-03 is the applicable technical document. The circuit opening relay probably is the relay that the dealer tech wanted to replace. This is located in the relay/fuse box between the inverter and driver's side fender.

The accelerator hesitation problem might be due to bad sensors in the accelerator pedal assembly. The issue is that one or both of the variable resistors in the pedal assembly get dirty and cause electrical noise. To see if this is the problem, when the car is IG-OFF try rapidly depressing and releasing the pedal about 30-40 times in an effort to clean the variable resistors. If this provides a temporary solution to those symptoms, then you know that the pedal assembly needs to be replaced. TSB EG018-02 is applicable to this problem.

Not sure why the air conditioning system is at "half power". Does this mean that the fan speed is reduced; or does it mean that the cold air coming out of the system is now at a higher temperature than before?

If you desire to keep your car long-term, it may be a good idea to repair some of these issues rather than allowing them to accumulate like enemies...

Perhaps you can locate a salvage battery assembly locally or via eBay, if so this will substantially reduce the repair cost of that item as compared to new.

[gippah]

By half power I mean that the AC is still cool, but the fan is only at half speed. Adjusting the thermostat has no effect except with regard to the temperature of the air, the fan speed would stay the same, even when pressing the "max" button.

I drove the car this evening, as it's only 90 degrees now instead of 100. The car drove much better at first, the triangle is still there but that takes awhile to clear. The fan in the trunk was obviously blowing the entire ride, which is unusual. The AC worked fine, but I didn't use it for about half of the trip because I wanted to be able to hear everything. The ICE stayed on for most of the trip.

But then something really odd happened. The car started revving loudly as I was going about 45 MPH, and at this same moment the "brake" light came on in the console. I pulled over w/o issue, although the car sounded like it was revving it wasn't increasing in speed, and although the brake light was on it was braking normally. I turned the car off and after I turned the key the engine still ran for a second or so before turning off. Upon turning the car back on, the brake light was off and the engine sounded normal.

At this point I don't think the car is safe to drive, so I'll be dropping it off at the dealership early in the week. I bet there isn't a TSB on this one, unless it's something awful like the transmission.

[tochatihu]

Perhaps premature ahead of HV battery testing, but you might contact LKQ Online and all their (salvage vehicle dismantler) competitors for bids. There may not be many available at any moment, and you want all the options known to you.

Also, nothing has been heard from Toyota on the subject of their battery renovating since a news article last September:

Toyota: Reconditioning Can Extend Hybrid Battery Life

You may be just the person to follow up on that possibility. Good Luck!

[Patrick Wong]

Originally Posted by gippah

By half power I mean that the AC is still cool, but the fan is only at half speed...
But then something really odd happened. The car started revving loudly as I was going about 45 MPH, and at this same moment the "brake" light came on in the console...
At this point I don't think the car is safe to drive, so I'll be dropping it off at the dealership early in the week. I bet there isn't a TSB on this one, unless it's something awful like the transmission.

I agree that the time has come to seek dealer tech help.

If the car is reving up more than it should, this implies that the hybrid vehicle ECU is desperately trying to charge up the traction battery. Did you have a chance to notice the reading on the traction battery SOC gauge at that moment? Or perhaps the hybrid vehicle ECU is being flaky and driving the engine ECU to rev up the engine more than normal.

If the fan speed dropped, could it be that the 12V bus voltage has decreased below the nominal 13.8V? At the time that the fan speed drops do you see any warning lights appear? The appearance of the "brake" light might also signify a problem with the 12V bus.

Please update us with the DTCs logged and the diagnosis provided by your dealer's tech. Thanks!

[gippah]

It only revved like that for a few seconds, until I turned the car off actually. Unfortunately there's no way to know what the battery charge was at that moment because the red triangle was on, and thus the console screen was different and not reporting the usual stuff.

The really weird thing to me about it revving is that the brake light turned on when it started doing this.

My gut feeling is that there's a short somewhere, perhaps in the battery array. This would explain why the fan is blowing all the time back there when it was pretty rare to ever have it blow before ... maybe it really IS hot back there due to a short.

It could be a short somewhere else too. Since this thing is drive-by-wire who knows what kind of weird stuff could happen with a short somewhere.

[john1701a]

You didn't mention either odometer reading or if you ever had the battery-seal TSB completed. That leaves us wondering. And whether or not you ever drove without gas is a big deal, much more common with the Classic than with HSD.

What we do know in general though is that batteries have a shorter life when routinely exposed to very high temperatures. So... thank you in advance for keeping us informed how southern late-life is dealt with.

.

[gippah]

The odometer is around 117k.

It has never been driven without gasoline.

The battery seal TSB was completed.

We don't know if the batteries are dead yet. Remember, the red triangle shows in conjunction with another symbol on the console screen -- and the symbol that is showing there is NOT the battery symbol, instead it's the generic "don't drive this car" symbol (the one on the right).

[ChapmanF]

I am expecting the diagnostic codes to remove a lot of the mystery. There really are several pages of known DTC and INF codes; the computers are likely to have recorded in fairly specific detail whatever it is they think is going on. Until we have those codes read out by the dealer, it may make more sense to relax, pick up a good book or go see a movie than to try to speculate about causes.

Re: the turtle light, I never had the sense that Toyota was trying to be cagey about what it meant. My owner's manual says (p. 94) "If the light comes on, the power will be limited." I don't think I ever took that to mean *I* should try to limit the power - it means I should drive as if I know I have limited power to use. The light will come on if for any of a variety of reasons (not just battery state of charge) the car is trying to save itself by not allowing high power to flow in motor, inverter, and/or battery circuits. (Don't forget that even simply getting ICE power through to the wheels requires electrical power flowing between MG1 and MG2 via the inverter - the car can't ever pretend it just has gears.)

-Chap