Motor Warning Light Comes On Shortly After Restart With Nearly Full Charge

[jbpatry]

I will start with the statement that I am very pleased with this car over the past 8 months after only a little bit of behavior modification. The issue that I have at the moment is that after heading home on my regular commute (down only 3 bars at this point) I sat waiting for about an hour with the ignition on accessory (Probably not significant) and on restart I was able to operate normally for only about 10 seconds before the Motor Warning light came on and had virtually no power. A terrible coincidence of this is that this very morning was my first visit to the Dealership on a warranty visit to replace the passenger side air bag inflator. I told the Service Manager that it was all his fault but would like to have it working and know what the actual problem is. Has anyone out there had similar issues?

Thanks,
John

2012 i-MiEV, 42k mi., JuneBug

[PV1]

Has it only done this the one time? Our cars, like all modern cars, are heavily software-dependent and prone to glitches. Most times, simply shutting down and restarting fixes issues.

It's quite possible that it was related to the 12 volt battery being run down a bit (something we'll likely see a lot more of in the near future as the stock 12 volt batteries wear out).

[jbpatry]

This is a consistent and repeatable sequence of error that the dealer is working on today.... waiting to hear. After sitting overnight it was able to operate normally for a greater distance (5 Minutes?) but then continued to fail. I will question the Service manager on the possibility of the 12 volt battery involvement.
Thanks,
John

[jbpatry]

Dealer could not find the cause and called Mitsubishi Tech Support that also directed toward the 12v system. They tested the battery to find that cold crank amps are above specs. They then drove it for another test drive that could not duplicate the error. My new theory is that in replacement of the inflator they pinched a wire that is a slow drain on the 12v system but just above the recharge rate. Maybe even a speaker wire. We'll see...
John

[JoeS]

I don't recall that specific problem being discussed here on this forum.

... A terrible coincidence of this is that this very morning was my first visit to the Dealership on a warranty visit to replace the passenger side air bag inflator. I told the Service Manager that it was all his fault ... but would like to have it working and know what the actual problem is. Has anyone out there had similar issues?...

Yes, ancillary damage caused by a tech rushing to complete a job is one of the reasons I am fearful of letting anyone touch my car. Case in point: when replacing some broken hardware holding up the front fender that my wife scraped a few years ago I was shocked at the number of missing plastic pegs which hold the front bumper cover and liners in place - the only work ever being done on the car had been airbag sensor-related by the dealer.

Yes, keep reminding the dealer that there had been absolutely no problem with the car before they touched it!

[phb10186]

I normally take a pic on my smartphone now before I take a car in for service. Proof that all the lights are off!

[jbpatry]

Left it with the Dealer for one more day to test and attempt to get more diagnostic info. After letting it sit over night at a parking lot near where it quit on my way home I was able to drive it normally to my office to recharge the drive battery and drive it to the Dealer (8.0 mi) without incident. I am questioning the effect of the step of disconnecting the 12v battery in the original air-bag work on the charging and vehicle control circuits.
John

[Aerowhatt]

I normally take a pic on my smartphone now before I take a car in for service. Proof that all the lights are off!

That's an excellent practice. I also put small chalk marks on the sides of the tires when getting wheels balanced, aligned etc. This way one can tell whether tires were moved around the car in the process.

Seems like a lot of the anomalous behaviors reported on the forum end up going away with attention to the 12V battery.

Without exception Lead acid (and most other chemistries) have rising internal resistance with age. Cold cranking amp tests are not a good benchmark for battery health. Basically that test equipment does not care how low the battery voltage sags as long as the amps are delivered. The I miev is sensitive to voltage from the 12v system. There are no "high cranking amps" but there are much shorter capacitor charging amps. To catch the peak would likely require an oscilloscope. If the voltage breaks the low bar during the "start up" then errors will result.

Also it isn't the cranking loads which keep ICE cars batteries better exercised as far as plate deposit cleaning goes. It's the high amp charge rate that the battery sees from the alternator after the cranking loads. So if one wishes to keep a "float" battery in better order one would discharge it to around half and then recharge at high amperage. The I miev DC to DC converter is more than capable of doing this with 60 amp charge rates available for the 12V battery while charging the car, or while in ready mode. The problem is that the high load on the 12V in an I miev is extremely short So the SOC of the 12V battery is not low enough to accept the high rate charge amperage. So it gets precious little vigorous exercise. So internal resistance rises undetected until these intermittent faults show up. In an ICE it would be more apparent because the cranking speed of the engine would slow and sound a bit labored with excessive voltage sag. Such a battery would pass a cranking amp test. But not sound strong staring the car.

Aerowhatt

[jbpatry]

The Motor Warning Light (little car with Exclamation point) and drop into crawl mode problem seems to be resolved but cause is still undetermined (Ghost in the Wire). I am very pleased with the extent that Burlington Mitsubishi Service Department went to to attempt to find the cause of this problem and then wanted to be sure that the car was operating reliably before returning it to my hands.
John

[JoeS]

jbpatry, I am glad that the dealership worked with you and seriously attempted to pursue this problem. You're on record in Mitsu's database as having this issue should it ever recur. I am closing this thread and, jbpatry, should you ever wish to revisit this topic please send a moderator a PM and we can reopen it. Thank you for sharing and your follow-up.