Engine & Gearbox Battery again and code P16A4

Discussion in '7th Generation (2003-2008) [Acura TSX]' started by Heckler, Monday 23rd Nov, 2015.

  1. Heckler Top Contributor ★ ★ ★ ★ ☆

    Car has been running sweet since that engine code about a month ago, and after the battery drain issue of 3 weeks ago... that seemed to be an anomaly that I couldn't track back to anything.

    This morning I came out and tried to start the car to find it wouldn't start... there was juice in the battery just not enough to fire it up. Clock remains the correct time and radio stations are still stored... so it's not a dead battery and I had it tested a couple of weeks ago.

    I charged up the battery with my charger for about 10-15 mins and that was enough to get it started. Had a 25m trip to do and it performed perfectly fine... But as I was driving along I noticed the engine light was on. When I arrived I plugged the code reader in and got a P16A4 with $12 after it... but think that last bit is superflous.

    After reading the codes I reset it and it hasn't come back.

    So what is that code?

    I think that I'll replace the battery regardless of what the test said... the sudden cold snap we had this last few days could have had an effect on the battery and whilst it seems to be holding the right charge and seems to be charging correctly... last 2 weeks I've done nothing more than 2-3 miles trips with heating often on along with heated screens and mirrors.

    I'm away for a few days so don't have access to some of the stuff at home... is the P16A4 to do with the swirl valve again or is it something new... Cold weather could have caused the swirl valve to stick too I guess.

    Either way... it comes at an inopportune time. MOT is due in less than 3 weeks and I've not serviced it yet nor run the cataclean through the system... it's further expense I could do without... but I can't risk finding a flat battery at random like this.
     
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  2. Ichiban Founder Staff Team

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    DTC P16A4: ECM Internal Circuit Malfunction

    That could be two things one your ECM is about to die or you need more software updates from a Honda dealer.

    As per WSM if P16A4 exists.
    YES - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.
    NO - Intermittent failure, system is OK at this time.
     
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  3. Heckler Top Contributor ★ ★ ★ ★ ☆

    Do you know how I can check what version of software I have and compare that to the latest it should have.... I'm assuming Honda will charge a pretty penny for an update.
     
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  4. Ichiban Founder Staff Team

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    Only at the dealers bud they will be using the latest MVCI and that will sense the code on your ECU and automatically state is anything is outstanding, If you have a good working relationship with your dealer then its will be FOC . if you don't then expect to pay 100 plus odd.
     
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  5. Heckler Top Contributor ★ ★ ★ ★ ☆

    I wrote the code down and then cleared them to see if it came back.

    Do you think it's possible that the code was flagged up because I started the engine whilst the charger was connected?
     
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  6. jimjams Expert Advisor ★ ★ ★ ★ ★

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    No, the code probably got flagged when you tried to start with the battery nearly flat.
     
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  7. Zebster Expert Advisor ★ ★ ★ ★ ★

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    I've had P16A4 a few times and seen it on other diesel Hondas. I'm satisfied that it pops up after the battery voltage drops below a certain threshold, but I have no links to back this up.
     
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  8. Heckler Top Contributor ★ ★ ★ ★ ☆

    Cheers @jimjams @Zebster obviously the battery was flatish and will be replaced later this week... Got a couple of long runs to do in the car today so that will give it plenty of topping up and see me through until I'm back home on Thursday.
     
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  9. Heckler Top Contributor ★ ★ ★ ★ ☆

    OK, I managed to get a much better diagnostic of the battery this evening on my way home... Stopped by a motorserv place near my folks.

    They had a much better device for testing the battery both off and with the engine running.

    The test came back good, but the device was more detailed and said the battery was 60% good... Normally they recommend replacing a battery if it drops below 50%... so it's getting close to that... and probably would benefit from being replaced.

    The running test came back great... with headlights on, was asked to run the engine at approx 3000rpm for a few seconds and that showed a charging rate of 14.24v which is excellent... So no issues with the charging side, it has to be the battery and I was quoted £72 for a new one with a 5yr warranty. Booking the car in for it's MOT next Friday. I filled the tank yesterday, and will be adding a bottle of cataclean to get to work over the next 9 days.

    I was also mistaken when I said the battery wasn't completely flat... it was flat enough to lose all the stored radio stations but not reset the clock which seemed a little weird.
     
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  10. Zebster Expert Advisor ★ ★ ★ ★ ★

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    It could still be a parasitic drain problem.

    A replacement battery would be far cheaper from Holdcroft Honda... They are probably still less than £50 and have a great spec (77Ah / 780CCA).
     
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  11. John Hamer Club Member ★ ☆ ☆ ☆ ☆

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    +10
     
  12. Heckler Top Contributor ★ ★ ★ ★ ☆

    Forgot to update this as I was discussing it in another thread too.

    Got a battery from HH delivered for £44.39... Didn't have time to fit it before the MOT on Fri (which she passed first time) as I was away most of the week... and today it's far too cold and windy to be outside. So when the weather improves a little I shall get out and fit it.

    Funnily enough, I've not had the same problem since... and I cannot pin down the cause of it. The car can be left for a few days and be perfectly fine... but twice now it's been left for around 60-72hrs and has been almost flat when I attempt to start it.
     
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  13. Ichiban Founder Staff Team

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    You don't have any aftermarket electrical device fitted to your car have you ? That could be causing this parasitic drain on the battery?

    The weather is shocking here on the M62 I had traffic cones whining around the three lanes ..
     
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  14. jimjams Expert Advisor ★ ★ ★ ★ ★

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    I reckon that there is something in the electrics on the 7th Generation Accord (no idea about 8th Generation, or other Honda's) that "crowbars" when the battery volts dip below a certain level.

    In particular, the volts on an old-ish battery (when the temperature has gone below 10-ish C) can start to dip after a couple of days. In a good old-fashioned car with simple electrics this would not matter, because the Ah left for starting is only going to be affected further in a linear way, by time. But I suspect that something in the 7th Generation Accord detects low-ish battery volts and turns on something on the CANbus, which then hastens the flattening of the battery.
     
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  15. Heckler Top Contributor ★ ★ ★ ★ ☆

    The only thing I have plugged in is the USB charger in the 12v socket... but as that is only active when the ignition is on, and I've pulled it out to test.... I can't think of anything else.

    The only things that I know of with a permanent feed is the headunit/clock. I even turned of the lights in the boot and the overhead door lights to see if something there was draining... but after a few weeks with them off and no repeat, I've kinda eliminated them.
     
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  16. Ichiban Founder Staff Team

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    No bluetooth device on your car?
     
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  17. Heckler Top Contributor ★ ★ ★ ★ ☆

    No it's a PFL so doesn't have that issue.
     
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