I have a 2014 Acura MDX SH-AWD with approximately 170,000 miles. I have an unusual intermittent issue during startup that happens 1-2x a year over the last 2-3 years. The Acura dealer has not been much of a help to diagnose.

When the problems surfaces, it happens when pressing the start button and the car starts along with several dash board lights remaining on and the informational scroll display listing multiple errors i.e. emissions, traction control, collision avoidance, etc. Sometimes, putting into gear after it starts with cause the car to shutoff right away or it can be driven in a limp mode (basically not changing out of first gear). Usually, reading and clearing the fault codes with my ODBII scanner will return the car back to normal and I am problem free from this issue for several months. I have also found disconnecting the battery resets the car for this specific start issue.

Yesterday, it happened again. Luckily, I was not far from my office. When the start initially issue occurred, it would even start. After cycling through the ignition by pressing the start button without the brake pedal, I was able to get it started and was able to drive back to the office with the errors on dash displayed. I did not have my reader with me, so I just disconnected the positive battery cable, waited a couple of minutes, reconnected, and the car started without any issues or dash light errors. Once I got home, my blue tooth OBD-Link MX+ reader did not find any faults during diagnostics. My Foxwell NT680pro did find single faults in multiple electronic modules. I cleared the faults after saving the readout report, but I have been unable to find the report just yet to review.

I replaced my battery in Oct 2018 and I do have a battery load tester at home. The last time I checked it was a couple of months ago and it was healthy. The terminals are clean and this car gets driven almost every day (usually 80-100 miles a day with mostly highway driving).

Just curious, if anyone has experienced the same thing and what might be the cause.

My concern is this issue appears to happen randomly and I never know when.

 

I would still suspect battery issue.

 

I tested the battery with a load tester and the battery was listed as good, cranking system normal, and charging system good.

I measured 12.50v (temp around 55 deg f) and 662 cca (770 cca factory new), which gave a soh 79% and soc 88%. I would have got slightly better numbers if I turned the auto lights off, but I wanted to simulate my normal startup. The charging numbers remained above 14v for both load and no load with a 36 mv ripple. The cranking volts was 10.28 at time 0.71 s, which maybe a little on the low end and I will likely confirm that using a better volt meter.

This would be much easier to trouble shoot if the issue occurred more often or consistently, but it only happens 1-2x in a year.

 

Still think you have a bad battery. Errors you described is exactly what I've experienced with our 2017 MDX SH. I was washing the MDX and left the door ajar for a few minutes with radio on. After 10-15 minutes, I tried to start the car, it wouldn't turn over. Bunch of lights popped up on dash just as you described...took it to dealer. They diagnose as a bad cell in the battery, they replaced battery under warranty. I was surprised because they tested battery/charging system just a couple months before and everything was in good shape. Since replacement car starts without issues.

You may have a bad cell in battery that's not apparent with your measurements. Our MDX battery died after just 2 years. I doesn't help that we are driving even less now during pandemic. I'd just replace the battery if I were you or get a trickle charger to charge when not driving as much. Newer cars now have lots of electronics on-board that is constantly draining your battery. Don't be surprise if your battery dies after 2-3 years. Even sooner if you live in extreme climate zone.

 

I'm having a similar issue and was wondering if you ever resolved yours.

 

There is no resolution to this issue. Every MDX even the new 4G will die with bad battery after a few days if you don't drive it much. Get a trickle charger that's the only remedy. This car has parasitic draw issues.