Has anyone here actually removed and replaced the alternator on the 3rd gen? I'm getting conflicting information about whether or not the intake manifold needs to be removed in order to have clearance to actually get the alternator out of the engine bay. I can see that I can access all the fasteners, but getting it out once disconnected looks very tight.

Removing the intake manifold doesn't worry me, it's pretty straightforward, but I'll need new gaskets (only available from Honda) and I don't want to buy those if I don't need to. At the same time, I don't want to go to all the trouble of unbolting the silly thing only to find out that I can't get it out of the engine bay.

I'm another victim of the "Check Charging System" + Power Steering, Stability Control + TPMS warning lights issue on my '15 EX 6MT ~60K miles.

It started on the first day of my drive from AL to CA in May. I'd just crossed into TX from LA when it first happened. I stopped at the next exit, (parked pointing downhill in case I had to roll-start) shut it off, and it started right back up. I got out my multimeter (I always take tools on any roadtrip) and checked the voltage at the battery. At ~3KRPM I had 14.2v, so far, so good. Then I did the old "pull the positive battery cable off while the car is running" alternator test. Car continued to run just fine. More or less convinced that the alternator was working fine, and since I'd just replaced the battery less than a month before, I continued on to my first overnight stop in Ft. Worth.

The next morning I was at Honda of Fort Worth before the service department opened. I wanted to get it checked over before I went any further, just for additional piece of mind. Funny thing, when I started it that morning, no "Check Charging System" message, no warning lights. After about a hour and a half, the tech said that the error codes in memory were related to a sensor reporting a low-voltage condition, but that had cleared. They checked both the battery and alternator and didn't find a problem with either one. They also didn't charge me a diagnostic fee since they didn't seen anything that would give them enough evidence to replace any components. (Kudos to Honda of Fort Worth!!!) He mentioned that one of the sensors in the system, close to the battery, can be heat sensitive and could possibly be the issue.

Back on the road, and no message or lights.......until I'd driven about 60 miles. Then the same symptoms reappeared. I should note that despite the Power Steering and Stability/Traction control warning lights being on, both systems were working perfectly. This continued for the next 4 days of my cross-country trip. If the car sat for ~2 hours or so, the warnings would clear, but would return after some driving. The outside temperature did seem to affect how long it took for them to return though.

Once I reached my destination, I took my car to Honda of San Jose, gave them the whole story and told them to keep the car as long as they needed to. I was going to be there for 2.5 months, and had access to another car, so I just wanted an answer to the issue before my return drive. After just a few hours, I got a call and went back to the service department. The tech told me that the problem was an alternator that was failing "intermittently" and causing all my woes and offered to replace it for the bargain price of only $840.00..........

That didn't sound kosher to me. As both an Electronics Technician with over 30 years experience and as someone who has been working on cars, motorcycles and farm equipment for even longer it seemed to me that "failing" alternator wouldn't have kept the car going and the battery charged for over 2000 miles of driving since the initial indication. I politely declined their offer and they charged me $185 for the "diagnostic fee". If I could access a factory service manual I am 100% certain that I could eventually get to the bottom of this. Car electronics don't scare or intimidate me in the least, but you've got to have the diagrams and other reference information in order to tell what the hell you are doing or looking at.

Just in case, I bought an alternator, and I still have it, still in the box it shipped in. I drove the car back to Alabama, 2,500 miles, and except for the warning lights and message, no problems at all. In fact, other than this issue, the silly little car performed brilliantly. It's probably the best long-trip small car I've ever owned.

So I'm now wondering how to proceed. My gut us telling me to replace the alternator and see if that clears it up, but first I'd kind of like to hear from someone who has actually replaced one.

If anyone has done this, please let me know. It would be greatly appreciated.

 

It's the same thing with the misfire codes that some 2015's have had at early miles. It's an intermittent issue but the car will be running just fine with the check engine light on.

 

I agree, but it's still annoying as hell and I'd really like to get to the bottom of it.

I'm thinking seriously about doing some voltage and current logging on the car as I drive it. I could either install something like the UltraGuage MX and use OBDII to access the alternator voltage and current, but I'm not sure it will record and log the measurements. Alternatively I could use a pair of voltmeters, one to measure voltage (could get that from the accessory jack) and the other to measure the reading from the current shunt that the car has installed between the negative battery cable and ground. I just will have to find out the specs on that shunt so that I know how to calculate the current from it. In theory, as long as I never see low voltage, or a negative current flow while driving, then I can be pretty certain that the alternator is, in fact, NOT having "intermittent" failures. Not sure I have anything here that will actually log the readings, but I could probably borrow something.

That will only give me more piece of mind, I'll still have the warning lights and message, so it's probably not worth my time.

I spoke with the service manager at my local Honda dealer today, the same dealership that I purchased the car from. The response I got does not give me any confidence that taking it back to them will do any good. She tried to tell me that the problem was probably because I have a non-Honda battery installed....... Gimmie a break. I've been in the military and commercial electronics field for over 30 years, there is nothing magic about a "Genuine Honda" battery. It's a lead-acid battery like any other, it is an Interstate Batteries MTP series, I've been using them for years, it almost certainly exceeds the OEM battery specs. It's also less than 4 months old. I find it very unlikely that the battery is causing my issue. It annoys me that dealer service folks so often assume that all their customers are clueless about stuff like this.

I do wish I'd read the threads here about replacing that teeny little 151R with a full size 51R. Honda undoubtably chose the smaller battery to save weight for fuel mileage considerations. I'd rather give up a few tenths MPG and have a battery with a greater storage capacity.

I'll probably eventually get frustrated enough to buy a month's subscription to Service Express so that I can at least have temporary access to the Honda service manual information. Once I have a good look at the design and configuration of the charging and monitoring circuits, then I should be able to get somewhere with it. At the very least I'll be able to find out if I really have to pull the intake manifold in order to remove and replace the alternator.

 

Intake does not have to come off to remove alternator. Here is sheet


Hope this helps

James

 

I know you're committed to the alternator, however the sensor and heat seems like a safe/cheaper place to start.

 

AGREE! Sure would like to know what sensor Ft Worth Honda was talking about. Did they happen to mention which one?

 

At work we had a diesel truck once getting the battery light come on at least once a week. Mechanic diagnosed some "spikes" in alternator voltage. We replaced the alternator and voila: problem solved.

 

Agreed. I'm 99% sure the sensor he was talking about is THIS ONE It's a current sensor, commonly called a "shunt". He said it was right next to the battery, and this one is. Essentially it's a VERY low Ohm resistor, it goes between the negative battery terminal and the chassis, ALL electrical current to and from the battery must pass through it to reach ground, so it can tell how much the battery is either charging or discharging. Essentially the ECU (or one of the other microcontrollers) can read the very tiny voltage drop (a few millivolts at best) and then since the resistance of the shunt is known, use that voltage to calculate the current because Ohm's law says that I-E/R (I=Current, E=Voltage and R=Resistance) An old-school car ammeter works exactly the same way.

If I can find one at a junkyard I may try that first, it's super-easy to replace, but, it would be pretty unusual for a shunt to fail, they are pretty simple devices. On the other hand, I do recall that their WAS a TSB issued about problems with some of these....and heat could be a factor.

Also, after reading all the threads about intake valve carbon buildup in these GDI engines, and educating myself about that issue (pretty interesting and terrifying at the same time) I kind of want to remove the intake manifold so that I can get a borescope and inspect my valves, so that's a vote for alternator replacement.

I just hate troubleshooting by swapping parts. I really like to know for sure before I start.

 

Thanks for that!!

 

They are salespeople.
Very few of the people you talk to have any real technical expertise. Service writers usually just parrot what we tell them, sometimes quite badly because many of them really don't understand the technical details. Sometimes it's like the writer just picks up on the important sounding words and spits them back out, without knowing it's all backwards from what we just said.. Like a game of telephone. I cringe hard sometimes.
Most customers have no need for technical details, and it works okay this way most of the time.
If you want technical details, you usually have to speak with a real tech. Then you can figure out if that person knows less than you do.


I'd like to know if it has LIN network related fault code(s) first
Based only on your story and seemingly temp related conditions, I'd also probably go for the battery current sensor as the cheap guess.

 

Whoa! I just posted my electrical woes that sound almost identical to yours! Waiting for moderator to approve the post as I'm new to the forum. Will cross post the link here once it's approved...

but do update if the shunt replacement takes care of it. I'm already two alternators (though only paying for one) and one PCM in already! ugghhh..

 

Just cross-posting my post here for quick access: Electrical woes