So, about 2 weeks ago, my 2006 MMH wouldn't start on the first key turn. Second time it was fine. Then I backed out of my garage, realized I forgot something, put it in park and shut it off. Ran back in the house, and when I tried to restart I got a "stop safely now".....which was odd since I was stopped and the vehicle wouldn't start! I turned the key to off and restarted without a problem. A few days later my wife had my car and said it took a few tries to get it to start....

As my MMH is 6+ years old (70,000mi) I did some reading and saw that the traction motor requires a minimum voltage or it won't turn over the engine. I tested the battery at 12.2v, then as directed.... ran the vehicle for a few minutes then shut it off. Turned on the headlights for a minute, shut them off and tested voltage. Turns out my battery would dip down to about 10v or less. I replaced the 12v battery..... and rigged a 9v to the 12v outlet in the center console to preserve KAM.

then more weirdness.

After installing the new 12v I started the vehicle and attempted to back out of the garage.... only to get an ABS light, a BRAKE light, and almost total brake failure. I shut down, restarted and got the same thing again. I assumed that it was something electrical that caused the brake system to not work, so I disconnected the negative battery cable, waited 5 minutes, and re-connected it. The vehicle started right up, brakes were fine, no problems since.

until today.

My wife was driving about 60mph on the highway when she said she felt a lurch as if she had shifted gears on a manual transmission.... and the exclamation point light came on and a "stop safely now" light came on. She pulled over for 5 minutes and the vehicle restarted and ran with no problems.


SO... my inclination is that

1. The dying 12v caused the first starting issue and the "stop safely" when already stopped, and replacing the 12V solved that.

2. At the same time, replacing the 12v did something odd that caused the brake system to not initiate... and disconnecting the negative cable 'cleared' whatever was causing that.

3. Today's "stop safely now" is totally unrelated and may be nothing or the start of a series of them. In reading the 22 page thread, it seems like 99% of those messages are either a failing coolant pump or a wiring issue. I had that battery connector recall done a while ago so I am pretty sure its not that.

I guess that all I can do is wait and see if I get another "stop safely now" and if so have the dealer try to pull codes?

 

Well, it happened again on her way back.... again driving along I-95.... vehicle just shut down. Very dangerous and scared her quite a bit. Luckily she was able to pull over and onto a ramp. I met her and drove home on the back roads with no problems. I noticed when I pulled into the garage that there was some odd noise coming from the front end.... sort of under the radiator fan area. Vehicle was on, engine off (EV mode) and also after turning back to Key On mode only. ...so from my reading that sounds like the MECS. Sounded kind of like a motor that was constantly changing RPMs....slowing down to a crawl, speeding up.... sometimes sounding like a fan with something tapping the blades as the spin.... but it definitely wasn't the radiator fans.

Dealer couldn't take it today so I'll drop it off with the advice that they check the MECS pump.


EDIT: Just happened again. I'm going to continue part 3 of this over at the big "stop safely now" thread
https://www.greenhybrid.com/discuss/...tml#post243635

 

I'd guess MECS pump - mine was faulty and had similar symptoms as what you describe...

 

Yes. It was MECS. I posted details in the stop safely now thread.


As for the ABS, the mechanic confirmed that after changing the battery the ABS system recalibrates, and it can cause that. He said that by cycling the key it would clear the problem and properly recalibrate, which it did. He confirmed the ABS codes were still present in the computer. (C 1524-A0 ABS, B 1318-A0 ABS)