I own a 2012 Honda fit sport that has 115,000 miles on it. Yesterday my check engine light and flashing D came on on my way to work however, by the time I got home for the day they were both off additionally, during the day I checked the code for the check engine light and the code stated the check engine light was not on even though it was. Should I be concerned or get it checked? I have never drained or flushed the transmission fluid. Should I do that? I do know that I need an oil change. I just got to 15% but I don’t imagine that’s the problem. Additionally, my car is driving perfectly fine and I’ve had no issues with the gears. I’d appreciate any advice thanks so much.

 

Most cars drive perfectly fine right up to the day when they stop driving perfectly fine. That day typically comes sooner without proper maintenance.

If you have never changed the ATF in 115K miles and you're getting a transmission fault (the flashing D), that should definitely point you in certain direction for what the problem might be.

The 15% oil life doesn't mean a lot in my book. Based on the rate it drops for me I would need to drive 4-5 years and 25K+ miles to drop from 100% to 15%. How many miles and how much time on your oil?

To answer your main question, if I ran overly long oil change intervals and neglected to do ATF changes then I would definitely be concerned when warning lights started flashing on the dash.

 

It has been 5 months and 4,000 miles since my last oil change, I wouldn’t say I neglect to change my oil, I just wait until my car says it is time. I have an oil change scheduled for Monday morning. Not sure if I should flush the transmission or just change the fluid at the time.

I really appreciate you replying!!!!

 

Now I am curious. What sort of driving do you do to get the oil life to 15% in 4000 miles? Mine has never dropped more than 20-30% in my annual 5000-6000 miles of driving.

There are many posts here about changing the ATF and the pros/cons of following the Honda procedure of a drain and fill, which only changes about 1/2 the fluid (if my memory is working), vs various procedures to change almost all the fluid. If you're having the work done at a shop they will probably recommend a flush and charge quite a bit for it. At 115K miles and nearly 15 years old the ATF in your car is.... not good, so changing it all is probably a wise decision as the Honda recommendation relies on the fact that you're changing 1/2 (or whatever it is) of the fluid approximately every 30K miles or 3 years to keep the overall volume of ATF relatively fresh.

 

Sounds like you're at minimum having a transmission pressure switch that is intermittently failing. I'd encourage at least codes pulled with an code reader or scan tool so you know what is going before spending time and/or funds chasing the concern.

Just as a general idea if the issue is per se the common 3rd gear pressure switch failure (P0847) and the circuit is fine with the proper power and ground specs... The general fix is to replace the 3rd gear pressure switch and it's sealing washer along with replacing the ATF.

The service interval for ATF DW1 is 2 years or 30k miles. From what I've seen in my area (along the Gulf Coast) those that defer ATF maintenance can see torque converter like judder after year 3 or after 40k to 45k of service when the ATF begins to noticeably degrade. Especially when the ATF is hot on models with a higher torque output (V6 Accords, Pilots, Ridgelines, Odysseys, etc). If you have zero history of ATF replacement, I'd encourage doing a 3 time drain and refill to cycle fresh fluid through the transmission and remove the old spent fluid naturally with each drain. Honda does NOT endorse using flush machines on their transmissions and the 3 time drain and refill method is their recommended method of "flushing" out old spent ATF.
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The maintenance minder system has an algorithm that the PCM runs taking engine run time, engine and coolant temperatures, engine load, and several other pids to calculate a projected service window. In more recent models were the gauge cluster and information unit (radio) communicate with each other for maintenance resets and message prompts, the maintenance minder factors in the date when the last reset was performed.

So older MMS vehicles like our Fits that see frequent short trips can easily see sub 4k or 5k before the 15% service prompt shows or those that see extended highway trips can see a range of 7k to 10k in rarer cases. Newer MMS vehicles like my 2025 Ridgeline will prompt the 15% service literally a year after the truck was built (in February), despite the fact that I only drove it 2,600 miles since taking delivery of it last April. These vehicles will sync the date with the maintenance minder after each start up then adjust the MMS percentage accordingly. This seems to be an adjustment of around 10% after every 36 to 43 days if my math is right. LOL

 

Over 5+ years of ownership I have never seen the oil life drop past 70% (and it only went from 80% to 70% once) in my 2010 Fit Sport before I do my annual oil/filter change at 5000-6000 (95% highway) miles. What you describe for newer vehicles incorporating time into the algorithm makes a lot of sense to me; that would make me actually pay attention to the system vs planning my own maintenance based on exclusively on time intervals.

There is also the "noob" ATF flush method described in a post here, which is what I did last summer. With a helper to cycle the car on and off while I was underneath monitoring the waste milk jug on which I had measured 1/4 quart intervals I was able to accurately drain (and refill) a quart at a time. It couldn't have been easier, and of course uses less fluid (saving you money and reducing needless waste) than the 3x drain and fill method.

 

I live in San Antonio, drive 20 miles to work which takes 40 min to an hour. Nothing crazy. My car would have higher mileage but I lived out of country for 4 years while I had it and it wasn’t driven much while I was gone. I will definitely changing out the ATF. Thanks!

 

Thanks! Not sure I’m handy enough to do it myself. I’ve watched videos and it doesn’t look too difficult, but it’s never quite as easy as it looks!

 

The basic ATF drain and refill is no more difficult than doing an oil change. If you follow Hootie's advice, you're just doing it several times.

You can also change the ATF filter which adds a few steps and some minor difficulty. I wrote about my experience in the "noob" ATF flush thread.

 

It honestly isn't hard to do at all. If you are savvy enough to change the engine's oil then you can replace the ATF. =)

But with the ATF being at least 4 years old, I'd definitely replace it with at least ATF DW1 or with an ATF that tolerates heat better than it. AmSoil's Signature Series Multi Vehicle ATF (which I run in my 5AT GD3) and Redline's D4 or D6 ATFs are the first three that immediately come to mind in that case.

Honda integrating time via the infotainment system is a nice feature as it does reduce the amount of effort to keep track of maintenance on the engine oil. Other times though, it can be a tad wonky with intervals like the 7 sub code for brake fluid replacement and 6 sub code for rear differential services prompting too early (and occasionally on some FWD models, LOL). So there is still some things to keep a mental note on.

As for the "noob" ATF flush post... I haven't seen it as I don't browse the forum nearly as much as I used to.

I tend to stick with Honda's recommended 3 time drain and refill since the vehicle gets ran through its gears while on a lift (or jack stands if D.I.Y.), ATF gets up to operating temp and cycled through the transmission during that time then drained out shortly after. Icing on the cake would be to replace the inline ATF filter mounted onto the transmission case after the final drain.