[dieseler]

My wife owns a 2004 Prius with 4700 miles on it.
Last weekend, in the rain, she experienced warning lights, then a loss of power on the interstate. Prius was towed to dealer who tested it and pronounced it perfectly okay. I notice the National highway Traffic Safety Administration site contains two such complaints. Any more?

 

[moocatdog]

My wife owns a 2004 Prius with 4700 miles on it.
Last weekend, in the rain, she experienced warning lights, then a loss of power on the interstate. Prius was towed to dealer who tested it and pronounced it perfectly okay. I notice the National highway Traffic Safety Administration site contains two such complaints. Any more?

A couple of people have posted here with similar descriptions. I have not seen any follow-up from them, so I don't know if a solution to their problem has been found.
Good luck,
Moo

 

[dieseler]

just saw similar problem

in Prius-Technical thread--please go there to add your reply.
By the way..rain seems to be a common denominator.

 

[mrv]

there's a battery TSB on this issue - but I haven't received a copy of it yet to tell you the details. EG027-04 (or is it GG027-04?) is a battery ECU reprogramming (separate from the SSC-40A and SSC-40D reprogrammings).

Or, the dampness issue was EG023-04. The first page of it was posted on priusonline.com recently. That replaces a wiring harness.

 

[moocatdog]

there's a battery TSB on this issue - but I haven't received a copy of it yet to tell you the details. EG027-04 (or is it GG027-04?) is a battery ECU reprogramming (separate from the SSC-40A and SSC-40D reprogrammings).

Or, the dampness issue was EG023-04. The first page of it was posted on priusonline.com recently. That replaces a wiring harness.

I had the wiring harness TSB completed on my '04. In my case it had nothing to do with a loss of power or dampness issue. The only symptom my car ever exhibited was the warning lights would occasionally come on, and for no apparent reason. So far, the repair seems ot have eliminated the problem.
Drive happy,
Moo

 

[BIF]

there's a battery TSB on this issue - but I haven't received a copy of it yet to tell you the details. EG027-04 (or is it GG027-04?) is a battery ECU reprogramming (separate from the SSC-40A and SSC-40D reprogrammings).

Or, the dampness issue was EG023-04. The first page of it was posted on priusonline.com recently. That replaces a wiring harness.

Thank you, Michelle. Has Toyota published any information on which cars may be affected by this?

 

[mrv]

there's a battery TSB on this issue - but I haven't received a copy of it yet to tell you the details. EG027-04 (or is it GG027-04?) is a battery ECU reprogramming (separate from the SSC-40A and SSC-40D reprogrammings).

Or, the dampness issue was EG023-04. The first page of it was posted on priusonline.com recently. That replaces a wiring harness.

Thank you, Michelle. Has Toyota published any information on which cars may be affected by this?

They usually have affected VIN info in the TSB.

But, alas, I don't have a copy of EG027-04 (or is it GG027-04?) yet.

 

[Marco Faust]

Very similar problems in a 2002 Prius with 60k: We have experienced frequent apparent losses of power on high speed interstate travel. It suddenly seems that we have to depress pedal farther to maintain speed (with no change in grade or anything).

Three times recently, following a reduction of power experience, the engine warning lights suddenly come on. But the car continues to go as if its still OK. About 4 miles later, however, the engine quits working and there is an inability to maintain high speed. The engine works intermittently, but just can't sustain itself. A mile later and it can barely maintain 30 mph (battery only obviously - with the warning light the power display isn't funtioning). Each time the gas tank was approaching about half full.

We pull off the highway. Let it sit for a few minutes. Start the car - the motor starts but warning lights are still on. Shut it off, and start again and it starts again with warning lights. Shut off again and turn on - engine works and the alarm is cleared. Three times is a charm.

Identical behavior three times in last two weeks. Light rain was present or nearby in two of the incidents but not in the third. Also in two cases I had been going up a slight incline and then immediately after shifting to a downhill slope (but only a slight down grade) the problem happened. Not sure of slopes on the other occurences.

BEFORE these three occurences for me, my wife had a similar problem. She come out of 7-11 on a hot day, started the car and the warning lights came on. She immediately took it to Toyota and they could find nothing wrong. They indicated that it could have been a gas cap not secoured fully. As a result, we have been carefully tightening the gas cap fully.

It appears to be a vapor lock is developing somewhere. The engine is truly starved for gasoline and that casues the warning lights. Rain is often associated with lower air pressure which could be instigating the vapor lock.

Anybody else? Whats the cure?

 

[BIF]

Marco, that's some great info you have included there. Very thorough, detailed, and complete. I think this is one of the most useful problem descriptions I have seen, because you have noted everything that happened during each of several occurrences.

I don't have an answer for you, but I sincerely hope somebody here will have an idea.

I am also a bit surprised that your service guy didn't find any error codes stored in the computer. I wonder, did they even check it? If not, I would insist that they do so the next time, even if you have to stand there while they plug it in!

Also, when your wife came out of the 7-Eleven, had she just filled up with gas, or was she simply stopping in for something from the store? The reason I ask is because my BMW started the engine warning thing, and the dealer didn't want to test it. They said they would have to charge me if it turned out to be a loose gas cap.

They nearly fooled me, too. I had decided to drive it another day or two to see if it happened again, and I drove away from the dealership. I got 3 miles down the interstate when the light came back on! I called my service guy right from my cell phone, and told him I'm bringing the car right back to him for full diagnostics. He agreed, and after they tested it, they discovered it was a bad O2 sensor or something.

My point is that service people (from all dealerships) typically like to say it's the gas cap, but unless they actually check the codes or test the car, they are really just guessing.

Good luck. I hope they find it and fix it very quickly for you.

 

[Marco Faust]

Clarification

Sorry to have left this out: They did find a code that they described as "could have been caused by the gas cap being loose". Also, they gave us a loaner (Prius) for a weekend plus Monday and didn't charge us anything. I'm bringing it back in today.

When my wife's occurence happened, the tank was almost full. She had filled up a couple of days earlier. Only one or two bars were gone on the gas display.

 

[mrv]

Very similar problems in a 2002 Prius with 60k: We have experienced frequent apparent losses of power on high speed interstate travel. It suddenly seems that we have to depress pedal farther to maintain speed (with no change in grade or anything).

Three times recently, following a reduction of power experience, the engine warning lights suddenly come on. But the car continues to go as if its still OK. About 4 miles later, however, the engine quits working and there is an inability to maintain high speed. The engine works intermittently, but just can't sustain itself. A mile later and it can barely maintain 30 mph (battery only obviously - with the warning light the power display isn't funtioning). Each time the gas tank was approaching about half full.

We pull off the highway. Let it sit for a few minutes. Start the car - the motor starts but warning lights are still on. Shut it off, and start again and it starts again with warning lights. Shut off again and turn on - engine works and the alarm is cleared. Three times is a charm.

Identical behavior three times in last two weeks. Light rain was present or nearby in two of the incidents but not in the third. Also in two cases I had been going up a slight incline and then immediately after shifting to a downhill slope (but only a slight down grade) the problem happened. Not sure of slopes on the other occurences.

BEFORE these three occurences for me, my wife had a similar problem. She come out of 7-11 on a hot day, started the car and the warning lights came on. She immediately took it to Toyota and they could find nothing wrong. They indicated that it could have been a gas cap not secoured fully. As a result, we have been carefully tightening the gas cap fully.

It appears to be a vapor lock is developing somewhere. The engine is truly starved for gasoline and that casues the warning lights. Rain is often associated with lower air pressure which could be instigating the vapor lock.

Anybody else? Whats the cure?

It's a faulty sensor in the accelerator pedal. You've got the error-code (worse) version of what once was called the Big Hand Syndrome (feels like a big hand is holding your car back, so you have to press harder on the accelerator pedal to maintain the same speed).

The good news: there's a TSB out on it for classic Prius. The bad news, at 60k miles you're out of the warranty period (3 yrs/36,000 miles). The accelerator pedal assembly (what'll need to be replaced) is over $300 when replaced out of warranty.

(BTW: the BHS usually is fixed with an ECU update.)

 

[BIF]

"Big Hand Syndrome." With all this Star Trek talk of late, the term made me think of that image of the original Enterprise being held in place by a big hand.

Sorry, I'm not geeky enough to remember the name of the episode. It's either that, or maybe I'm too savvy to admit it? Heh, YOU be the judge!