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Request for Advice 2007 Dodge Caliber...

08/21/2017 7:39 AM

I have a 2007 Dodge Caliber with a defective charging system. After verifying wiring integrity and testing the alternator out of the vehicle, it appears that the problem is in the ECU. Is there any way to install and wire an external voltage regulator to bypass the defective ECU? It has been a good car; I don't want to spend a lot of money on it. Thanks,

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#1

Re: request for advice 2007 Dodge Caliber...

08/21/2017 7:41 AM

Why not just get a replacement ECU out of a "scrapper"?

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#2
In reply to #1

Re: request for advice 2007 Dodge Caliber...

08/21/2017 7:44 AM

The ECU is tied to the vehicle through the VIN, as well as mileage. I appreciate your response...Thanks...

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#5
In reply to #2

Re: request for advice 2007 Dodge Caliber...

08/21/2017 6:26 PM

You can flash the 'donor' ECU with the VIN and mileage information. My son purchased one of these professional scanners that set him back about $6k because he's in the business of modifying cars for the track. Chances are you can find an independent shop that should be able to do that for you.

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#3

Re: request for advice 2007 Dodge Caliber...

08/21/2017 10:28 AM

Appreciating that you do not want to spend a lot or spend time building a regulator, can you get the regulator off a previous model of the generator which was not tied to ECU or even the entire generator/regulator from a "scrapper"? Dodge Caliber is foriegn to me so I do not know any specifics.

The fact that you could prove the generator works off-engine suggests it is probably still "simple" with a brush to the rotor field. Any regulator is then a "3 terminal box" with one terminal to battery plus, one to field and one to battery minus [probably by being bolted to generator]. In that case, hooking-up an external regulator is not complicated. You need to watch out if the regulator was mounted to be air blast cooled by the generator fan because it might overheat without.

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#7
In reply to #3

Re: request for advice 2007 Dodge Caliber...

08/22/2017 1:32 PM

That sounds like a good idea, I'd just add that alternators from about 1975 until ECU control came in all had built-in regulator, so there shouldn't be any need for an external regulator.

It doesn't have to come from a 2007 Dodge Caliber, any alternator with roughly the right output, correct pulley and mounting arrangement is OK.

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#4

Re: Request for Advice 2007 Dodge Caliber...

08/21/2017 1:49 PM
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#6

Re: Request for Advice 2007 Dodge Caliber...

08/22/2017 1:25 PM

You say "it appears that" the problem is in the ECU, but what makes you think so? Does the ECU show any other symptoms? Seems a bit odd if only the alternator control function has failed.

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#8
In reply to #6

Re: Request for Advice 2007 Dodge Caliber...

08/22/2017 2:39 PM

...all of my wiring checks out. The only common denominator is the control of the alternator field current in the ECU. From what I have researched, this is not an uncommon problem...

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#9
In reply to #8

Re: Request for Advice 2007 Dodge Caliber...

08/22/2017 3:21 PM

OK. This sort of thing has been discussed here a few times. The links below might help, the first one contains a wiring diagram of ECU control

http://cr4.globalspec.com/thread/105428

http://cr4.globalspec.com/thread/79539

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#10
In reply to #9

Re: Request for Advice 2007 Dodge Caliber...

08/23/2017 9:07 AM

Don't know whether you could open those links, I did it in a hurry. Ones below are neater if nothing else!

Alternator 1

Alternator 2

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#11
In reply to #10

Re: Request for Advice 2007 Dodge Caliber...

08/23/2017 4:16 PM
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#12
In reply to #11

Re: Request for Advice 2007 Dodge Caliber...

08/25/2017 7:51 AM

Interesting links. Says

One of today's major challenges for carmakers is improving the fuel efficiency to reduce the vehicle's fuel consumption and its carbon footprint. The efforts to achieve greater efficiency need to start at the charging system, our authors say - key element is a new alternator regulator IC.

That sounds to me like overdoing the salesmanship. It doesn't say anything about how the improvement happens, as far as I can see. The only thing I can think of is it might somehow allow near-zero current when the battery is fully charged, as opposed to 2-3 amp trickle charge from conventional set-up when the battery is up to voltage. The battery still has to be charged to that point. I don't think you'd notice any difference in mpg. Would save more by discouraging drivers from using headlamps (or more) irrespective of need, using 10-15 amps.

Possibly reducing the trickle charge might increase alternator life, particularly brushes. My current one, with ECU control, has done > 190,000 miles without problem. But negligible effect on efficiency IMHO.

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