Piston Slap: Unfit to Charge a Fit?

Sajeev Mehta
by Sajeev Mehta
piston slap unfit to charge a fit

TTAC regular Ronnie Schreiber writes:


Tonight, while driving on the interstate, the tire pressure warning light came on in my ’15 Honda Fit, then the ESC light came on, then the power steering warning light came on, and then the info display said to check the charging system. Everything seemed to be working just fine, though. I pulled off to check the serpentine belt, which was intact so I started searching on the internet for the symptoms.

According to the forums, it’s sort of a known problem that’s due to glitches in the electrical system causing erroneous fault codes. Dealers usually try replacing the alternator, which doesn’t help. The alternator harness, the ABS sensors, and the injectors/coil packs have all been mentioned in the forums as fixing the problem.

I’ll check all the connections in the morning, but in the meantime I’m leaning towards a faulty ABS sensor, since those are used for the TPMS in my car, not an actual pressure transducer, and the first light that goes on is for tire pressure. Also, the check charging system warning was intermittent.

What do you think?

Sajeev answers:


I bet it’s a weak battery, how old is it?

Ronnie says:

OEM battery on a ’15 model with about 64,000 miles. Seems to crank the engine normally.

Sajeev adds:

Sounds like it’s way past its expiration date. I’d get it tested, odds are it’s about to die.

Well, in my experience that’s the case.

Ronnie says:Thanks. The battery is tiny and I’m sure that the way Honda manages the automatic headlights doesn’t help. When parked, the lights stay on for a long time unless you lock the car, in which case they stay on about long enough to get in the house.

Sajeev concludes:

While it could be corrosion, loose connections, bad grounds, etc. I am somewhat more confident in my diagnosis: for the past 25-ish years, vehicles have been known for bizarre behavior because of failing cell(s) in a battery. The car will still start fine, and not trigger any voltage error (gauge or idiot light) either.

I first learned this with my parent’s leased 1999 Lincoln Continental, but the processor-heavy flagship Ford (automatic everything, including steering and suspension feel) is far from an outlier in today’s module-laden vehicles. And it’s an electrical lightweight compared to a hyper complex/sensitive, modern luxury car! My first experience wasn’t my last: from late model Mustangs to BMWs, I’ve felt a 3+ year-old battery is ticking time bomb, especially in the brutal heat of places like my Houston.

What say you, Best and Brightest?

[Image: Honda]

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.
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8 of 32 comments
  • Pwrwrench Pwrwrench on Oct 04, 2019

    Yep, Battery likely cause. This happens in ancient stuff also. My beater van is 35 years old. Recently it had occasional slow cranking. Finally battery voltage dropped below 10 V and the starter refused to crank the engine. No amount of charging helped. Replaced battery and Ops checked good. Charging system, wiring, cables, and grounds were all checked before battery change and found good. New one for me was a part throttle surge that I thought was likely a vacuum leak was fixed when battery was replaced. In the past I have seen failing batteries cause all sorts of odd things to happen on dash instruments.

  • Rpn453 Rpn453 on Oct 04, 2019

    Not saying the recommendation of a battery replacement isn't a good place to start, but I disagree that a battery of that age should be assumed to be expired unless it has been completely discharged at some point. The Panasonic in my '04 Mazda3 lasted more than 14 years.

    • See 5 previous
    • PandaBear PandaBear on Oct 08, 2019

      Even for Panasonic, lasting 14 years is unusual. I wouldn't use that as a way to judge how a car battery typically last.

  • Kwik_Shift If I'm in that situation of being in an unfamiliar area looking for an address/parking, I'll put on my hazards. If you want to pass, then pass. Otherwise you have warning.
  • Tassos Strictly a collectible, nota daily driver. Way too old. Even the Awesome S class from 1991-99 is getting to old to be a daily driver these days.
  • MRF 95 T-Bird The small van segment is quite popular in Europe. Many business owners and crafts people buy the Transit, the Renault Kangoo or Peugeot Partner since it fits their needs and can navigate the narrow streets. They should have done better here for folks whose Ranger or S-10 with a cap is getting old.
  • Kwik_Shift So well-used ones can be overpriced.
  • Cprescott Ford killed the TRANSit because it identified itself as a station wagon.