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2008 2.2cdti AWD EX-L
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Discussion Starter · #1 ·
Hi, I have seen that Honda use an ELD to vary the alternator charge voltage/capacity , however I have also seen electrical schematics which seem to suggest that the use of an ELD is restricted to US Honda models - my question is whether this is strictly true or UK Honda CRV's use an ELD. I have a charging issue with my CRV which is pointing to the alternator having variable output ( 10-14V) - however maybe if the UK models also use an ELD, then maybe its not so much the alternator but the ELD which is causing the problem ?

Looking for clarity on whether UK Honda models employ ELD circuity ?
 

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Hello,

What year and model to better understand your question?

I'll give a brief rundown on what ELD is and how it functions in most models in the U.S. before the global advent of LIN bus communications between the PCM and alternator which then makes the alternator a true "variable output" matter.

Electrical Load Detection (ELD) is really nothing more than an inductive clamp placed over the main electrical feed into the Under Dash Fuse Box (UDFB).

As charge voltage and current leaves the alternator it splits off at a "Y" junction with one branch of the "Y" going to the battery to charge it and the other headed to the vehicle's electrical system via UDFB to power the vehicle.

This branch that heads towards the vehicles main electrical system has the inductive ELD clamp placed around it so the PCM can monitor how much current is actually flowing into the vehicles electrical system (vehicle side electrical demand) in real time.

Since the PCM can monitor battery voltage directly through it's own power and ground source, it can take this direct voltage sample and couple it with the vehicles current electrical operating demands (how many amps are flowing into the vehicals electrical system) to determine if some fuel can be saved in requesting the alternator lower it's high output map (14.5v) to it's low output map (12.5v).

If the PCM see low electrical demand (low vehicle current demand), coupled with high battery voltage (14.5v), then the PCM sends a message to the alternator requesting it to cut it's output to the lower 12.5v map.

You can see all this take place in real time if you have an i-HDS to access the PGM-FI data list.

You would look at:
  • Battery voltage.
  • Alternator output amperage
  • ELD (vehical power demands in percentage)
  • Alt Cntrl (PCM alternator control request) 14.5 = high output request, 12.5 = low output request.
We have a lot to think about here, but let's 1st understand what you have.

I hope this helps,

Cheers!
 

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17 CRV EXL AWD, 14 CRV EXL AWD
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Prior to the 5th gen crv, the ELD module was located in the engine bay fuse box as shown in the attached photo of a 2002 CRV. The ELDs in different generation crvs would be in slightly different locations in the fuse box but pretty much looked the same. In my US 5th gen crv unlike my 4th gen, I don't see an ELD module nor can I find a part listing for one. Doesn't mean there isn't one, I just can't find it. But since the 5th gen can see pretty much the status of every load device on the vehicle now, having an ELD would be redundant and Honda may have simply eliminated it for cost savings. Honda would only have to program the PCM to adjust the alternator's output based on what is turned on and the conditions the vehicle is operating in.
 

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