red warning light?!

[ikklesmiler]

Sometimes when I start my Prius I get the red master warning light come on (the triangle one)
If I switch off the car and restart again again it doesnt normally stay on.

Its a bit worrying why this would happen quite a lot. Any ideas?

Ann Marie

[Sandy]

could be anything, you need to have the codes, i would not drive it that way.

[Patrick Wong]

If the master warning light is the only one to come on, maybe the 12V auxiliary battery is weak.

[cgates30]

I might be having the same problem. I've got an '06 with 67,000 miles and in the last couple of weeks I've noticed the red triangle light comes on (most of the time) when I first start the car. It turns off in 3-4 seconds and the car drives normal, etc. It doesn't come on all of the time, but probably 80-90% of the time. I'm reluctant to take it to the dealer (they wanted a couple hundred just to change a light bulb). Does the red triangle indicate the car has through some codes? Would Autozone be able to read the codes?

[richard schumacher]

Start simple: check the 12V battery. You can do this yourself, either with a voltmeter at the jump point under the hood or with the following no-tools selftest procedure (thanks to jdenenberg):

- Without brake pedal, press the Power button once and release to enter ACC mode
- Press and hold the MFD Info button while turning the headlights on and off three times to enter Maintenance mode; release Info button
- Press “Menu” (on screen)
- Press “Display Check”
- Press “Vehicle Signal Check” - the battery voltage is shown and should be about 12.4 to 12.8 Volts (normal for an unloaded battery)
- Again without brake pedal, press Power button and release to put a current load on the battery - the voltage should stay above 12.0V (if less than 12.0V the battery is not well, or there is a fault or unusual load somewhere)
- Press brake pedal and press Power button once to enter "Ready" mode - the battery is now charging at about 14V (if less than 13.6V or more than 14.4 there is a problem, possibly with the charging circuit)
- Turn car OFF to leave Maintenance mode

[cgates30]

Originally Posted by richard schumacher

Start simple: check the 12V battery. You can do this yourself, either with a voltmeter at the jump point under the hood or with the following no-tools selftest procedure (thanks to jdenenberg):

Last night I got a call from my wife, she was stranded because the Prius wouldn't start. The kids had been waiting for her in the car with the radio and headlights on. After about 20-30 minutes, the car wouldn't start. I jumped the battery and since then the red triangle hasn't come back on, so I'm guessing the problem was related to the 12V battery. I went through the Mnt mode procedure above and the voltage under load was 12-12.1V and in charging mode it was 14-14-4. I did turn the lights on and the voltage dropped to 11.6V, so they do really draw it down.

Thanks for telling me what to look for.

[richard schumacher]

Good, a bad battery is a relatively cheap and easy problem to fix. Having been drained a couple times now it probably doesn't have much life left in it. The accessories will drain even a new one pretty fast.

[jdenenberg]

Originally Posted by cgates30

Last night I got a call from my wife, she was stranded because the Prius wouldn't start. The kids had been waiting for her in the car with the radio and headlights on. After about 20-30 minutes, the car wouldn't start. I jumped the battery and since then the red triangle hasn't come back on, so I'm guessing the problem was related to the 12V battery. I went through the Mnt mode procedure above and the voltage under load was 12-12.1V and in charging mode it was 14-14-4. I did turn the lights on and the voltage dropped to 11.6V, so they do really draw it down.

Thanks for telling me what to look for.

Now that you know to get a new 12v battery, look at the deal from elearnaid on eBay. It includes all the required adapters (cable connectors and vent tubing) as well as a yellow-top Optima 51 battery (better than the the original).

JeffD

[CharlesJ]

Originally Posted by richard schumacher

... The accessories will drain even a new one pretty fast.

Especially with the headlight on, it goes fast; lots of power to the lights compared to a car radio.

[cgates30]

Originally Posted by jdenenberg

Now that you know to get a new 12v battery, look at the deal from elearnaid on eBay. It includes all the required adapters (cable connectors and vent tubing) as well as a yellow-top Optima 51 battery (better than the the original).

JeffD

Couldn't find the seller on ebay. elearnaid? Thanks

edit: found his website, http://www.elearnaid.com/12vo1topraub.html