CEL will remain after IMA/12V light go out for a period of time.

The disconnect/reconnect reset everything.

I suspect that your only issue is the 12V battery. My first IMA code in my '06 was due to a bad 12V battery.

If the red 12V battery light is off, 12V charging should be good.

I use a cigarette lighter voltmeter to monitor my 12V health. At 1500 rpm, you should see >13V if charging system is working (typically around 13.9V if the battery needs the charge with occasional jumps to a bit over 14V).

I like this one:


It annoyingly shows interior temp in °C, USB port charging current and input voltage on a rolling cycle, but the combination of info + USB charging ports is pretty handy if you don't mind waiting several seconds to see input voltage.

Other options:



One in the armrest port is handy too if you want to keep your regular USB charger in the front port.

Steve

 

Well hell - I thought we had it solved. I run out, pick up the 51R, put it in, start the car, and all the lights are back. Battery/IMA/CE. I think maybe it's a little weak off the shelf, so I hook up the Highlander again. Highlander's running at about 13.65v. Try again, still the same. Then I try a reset - unhook the Honda 12v, wait, rehook and go straight to adding in Highlander support. Still the same. Can't figure out what went right for those few starts this morning when I had it hooked up to the Highlander and what's wrong now.

 

Did the motor spin with the IMA or crank like a regular car?

Still the same codes?

 

Cranked like a regular car. I don't have a reader, so I'll have to go to a parts store for a new reading.

 

It is possible that relay is bad. Never heard of it happening, but anything is possible.

I recommend a bluetooth code reader from amazon ($11) and torque Pro for android ($6) to read your own codes more accurately than your typical auto parts store OBDII reader.

 

Code reader will be here Friday.

In the meantime, here's a nice little plot twist. I start it this morning to go to work and it decides to work right off the bat. IMA and battery lights gone. 20 minute drive to work and I've just kept the whole seat and panel off while I continue to work on diagnosing, so I can hear the buzz of electricity as the system works. Halfway in on the highway as I lightly accelerate, I hear four short buzzes (and one blinking bar of assist) and all three lights come back on and the assist dies once again.

Given this new info - new question. Does the main battery relay click on only once when the car starts or does it activate/deactivate with each request for assist?

 

To my knowledge, it clicks on once. With it off, 12V charging is rpm dependent.

If it's intermittent, you occasionally get normal function. If that part doesn't cost a lot, it's probably worth replacing it.

I must caution you on driving with the IPU lid off. You have ZERO battery/electronics cooling aside from natural radiation and convection. The fan exhausts in the trunk, creating a vacuum in the cavity and drawing air in from the vent on the rear deck, through the battery, over the electronics and out. With the lid off, the fan is just sucking air from the corner and shooting it into the trunk.

 

Majestic Honda is a favorite:

http://www.hondaautomotiveparts.com/...VIN+Number+---

With all things being equal, I would order from Majestic due to positive past experience.

Steve

 

Got the code reader. First reading showed P1515 and P0AE1. Reset and now only getting P0AE1.

Waiting for the part to come in. Won't ship until Tuesday, so hopefully will have more answers or a possible fix by next weekend.

 

Precharge contactor came in. Replaced it, but it fixed nothing.

New info: step 26 of troubleshooting says to check for continuity between BCM connector A13 and body ground. This step failed and it basically says to check for loose connections or terminals at the junction board/BCM. I've checked the whole thing - pulled off the junction board, checked all the connections, put it back together, and still nothing.