P0603

[HPO]

I have just purchased a 2006 Pilot EXL 4WD, with 65K, from a local Honda dealer. After 2 weeks the CEL came on. I do my own work and have an OBDII code reader and read out the code as P0603 which is "Internal Control Module Keep Alive Memory (KAM) error". I have reset the DTC code and it has not returned.

Has anyone ever experienced this error on a Pilot (or any other car)?

The KAM b+ voltage is on all the time to retain the learned memory in the PCM (ECM). It is a false indication as the memory is not lost and the car runs flawlessly. I have reason to believe that this may have been an intermittent problem with this car for a long time. I have a call in to the dealer and the original local dealer who previously serviced the car but have not heard back from them.

I have a theory, but would like any possible feedback. Thanks.

[rocky]

Since the car runs fine, I wouldn't worry about it.

It can be triggered if you disconnect the battery etc. Check the connections. Any aftermarket alarm system or wiring on the car?

http://engine-codes.com/p0603_honda.html

[HPO]

Originally Posted by rocky

Since the car runs fine, I wouldn't worry about it.

It can be triggered if you disconnect the battery etc. Check the connections. Any aftermarket alarm system or wiring on the car?

OBDII Code P0603 HONDA - ECM Internal Keep Alive Memory Error | Engine-Codes.com

Thanks. All good thoughts.

The dealer had installed a new 100 month Honda battery, and installed it very well. No corrosion or bad connections at the battery. I have not checked any other connections but will do so when I receive the service manual. No aftermarket products that I can see.

It could possibly be the ECM(or programming), but for now I doubt it.

I am not worried about it except if it comes on often it masks other potential problems and must be reset each time. If it comers on once a year that would be OK.

[theirishscion]

I wouldn't be so quick to assume that the memory was not lost without a factory scan tool to verify it, especially on a vehicle that is unfamiliar to you. Idle air, stochiometric compensation map and even learned transmission shift strategy can usually be lost without any dramatic variance in how the car performs.

I've not done so on my Pilot but my 2003 Explorer (which stores all the above parameters and more in much the same fashion) has repeatedly had that memory reset for various reasons, and even after 110,000 miles experience driving it since new, I'm hard pressed to spot any difference is engine or transmission behavior, though it does run a bit richer on the first cold start after a reset.

With that said, ECU failure is extraordinarily rare. The mantra I hear from apparently knowledgable folks over and over again is that whatever is wrong, it probably isn't the ECU. This seems to hold particularly true for Honda.

< edit >You can ignore the following paragraph since that's already been addressed specifically, though I would be a little inclined to check all the connectors between the battery and the ECU for corrosion or backed-out pins.< /edit >
My suspicion, for what it's worth, is that you might have a marginal battery (or corroded battery terminals, or iffy cabling or so forth, you get the picture), leading to a sufficiently extended brown-out to the ECU to corrupt or reset it's memory.

Tell me, why do you get the impression this has been an ongoing problem?

[ichu77]

Got the same issue I encounter at 65K, only to find out my OEM honda battery is dying. Did battery change and did relearn idling.So far everything is running smoothly.

[2010exl]

I had a P0606 code on a 2005 Corolla...it relates to something similar with a loss of some memory. Toyota had issued a recall for replacement of the ECM because of a defect on one of the circuit boards. The problem has not returned.

Its possible that the car sat for an extended time period before you purchased it and that may have contributed to the code coming up. I also saw a similar error (dont recall the exact code) on a 2004 Dodge Ram 1500 that sat for 3 months over the winter.

[HPO]

Originally Posted by theirishscion

I wouldn't be so quick to assume that the memory was not lost without a factory scan tool to verify it, especially on a vehicle that is unfamiliar to you. Idle air, stochiometric compensation map and even learned transmission shift strategy can usually be lost without any dramatic variance in how the car performs.

Tell me, why do you get the impression this has been an ongoing problem?

You are right. I don't know for sure. It just seems to run fine.

The Carfax showed that in 2007 the following occurred:
"complete PCM scanned and tested"
"complete starting system scanned and tested"
"complete electronic system scanned and tested"

Not normal maintenance. They were looking for something electronic. May be completely unrelated.

It has occurred again(within a week). The dealer said he will cover it. I take it in Wednesday. I'll let you know what they fine.

[theirishscion]

Not to sound too paranoid but I would ride them hard for an explicit resolution to this, not just a 'well, it seems to be fine now, sir' answer.

It's not the end of the world if it does this thing once or twice a year, but any more than that and I'd be quite concerned that you're the one in a million with a bad ECU, or more likely a bad earth or connection elsewhere.

[HPO]

The dealer replaced the PCM(ECU) at no cost. Can't beat that kind of service. Kind of surprised me as there is no warranty. They said they cover the power train for the first month on all Honda used cars they sell.

Time will tell if it fixes the problem.

[theirishscion]

Well, even if it doesn't, they've already replaced the most expensive thing it could possibly be. If you have to go chasing ground wires, it'll pain a pain in the bum but not terribly expensive.