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2006 xc 90 V8 New alternator new tensoiner belt slipping

A mid-size luxury crossover SUV, the Volvo XC90 made its debut in 2002 at the Detroit Motor Show. Recognized for its safety, practicality, and comfort, the XC90 is a popular vehicle around the world. The XC90 proved to be very popular, and very good for Volvo's sales numbers, since its introduction in model year 2003 (North America). P2 platform.
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jimmy57
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Re: 2006 xc 90 V8 New alternator new tensoiner belt slippin

Post by jimmy57 »

The alternator is the most sensitive to reverse polarity. The control units usually have internal protection and should be OK.

VFLXC90
Posts: 59
Joined: 21 April 2012
Year and Model: XC90 V8 2006
Location: Joliet IL.

Post by VFLXC90 »

Seems to be the ALT.
It ran for 10 min at idle full load, A/C ,Heated seats, rear defrost est. Held 14.2 V. After 10 min, still under full load it would drop to 11.4 and go up to 12.2. You could hear the engine fluctuate with the load. It idled for 40 min under full load 11.4 to 12.2. Drove it down the street the light came on. Now its a steady 11.2 v and its not kicking on off like it was(engine load like above).
Once it cools down, it will read 14.2 like above then drop again.
So its probably the ALT.?
08 XC 90 V-8 157,000 Spouse
06 XC 90 V-8 141,000 Daughter
06 XC 90 V-8 234,000 Son
03 V 70 2.5 Non Turbo

VFLXC90
Posts: 59
Joined: 21 April 2012
Year and Model: XC90 V8 2006
Location: Joliet IL.

Post by VFLXC90 »

jimmy,
Is the voltage regulator seperate from the ECM? Is it separate from the ALT.
Is it possaible the ECM is damaged? (reverse polarity)

Concerned with your post indicating below.
The alternator has a communicating voltage regulator. The control units usually have internal protection and should be OK
08 XC 90 V-8 157,000 Spouse
06 XC 90 V-8 141,000 Daughter
06 XC 90 V-8 234,000 Son
03 V 70 2.5 Non Turbo

jimmy57
Posts: 6694
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Post by jimmy57 »

The alternator control module, ACM, previously known as the voltage regulator, is separate but I don't think that the one for that model is sold by anyone.

I doubt that the ECM is harmed.

My opinion is that the alternator charges until the ACM quits.

It won't be easy to do but you can check this by monitoring voltage on the small gauge wire lead into alternator. It will have battery voltage +0/- 0.8V before engine starts and once engine runs it will be a little over charging voltage. If the ACM goes off then the voltage should be about battery voltage again.

You can bare about 1/2 inch of a small gauge piece of wire and stuff that 1/2 inch into the ACM connector from the rear and read that remotely. Voltage measurements don't care about length of wire as long as the connection into the ACM wire is good.

VFLXC90
Posts: 59
Joined: 21 April 2012
Year and Model: XC90 V8 2006
Location: Joliet IL.

Post by VFLXC90 »

jimmy,
Thanks for all the help on this one!!!
The ACM is attached to the alternator under the black plastic cover that is on the back side of the ALT?
ACM is connected to the plug that is attached to the alt? The the small wire clips into that plug.
That's were I check for 8v not running?
Once its running it should read around 14.2 v at idle charging voltage?
When the ACM kicks out, it should read battery voltage until ACM kicks back in?
Does above sound correct?

If I install my replacement undamaged Alt. and I preform above and its determined the ECM is damaged. Can this cause my replacement ALT. to become damaged due to bad ECM?
08 XC 90 V-8 157,000 Spouse
06 XC 90 V-8 141,000 Daughter
06 XC 90 V-8 234,000 Son
03 V 70 2.5 Non Turbo

VFLXC90
Posts: 59
Joined: 21 April 2012
Year and Model: XC90 V8 2006
Location: Joliet IL.

Post by VFLXC90 »

jimmy,
I have 7.7 v key on. Not running.
After I turned key off, it held 7.7 just before it powered down, spiked to 10.2v then to zero.
ECM?
I have Alt. out of it, so I didn't do the run test.
08 XC 90 V-8 157,000 Spouse
06 XC 90 V-8 141,000 Daughter
06 XC 90 V-8 234,000 Son
03 V 70 2.5 Non Turbo

scoobdude
Posts: 2
Joined: 17 November 2013
Year and Model: 2007 XC90 V8
Location: Texas

Post by scoobdude »

I had read somewhere that there were 2 different part numbers for the alternator. One did not have the right regulator.

Here is the link with part numbers and alot of info, hope it helps
http://andrewpeng.net/cars/2006-volvo-x ... eplacement

jimmy57
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Post by jimmy57 »

Sounds like correct voltages so ECM seems good. Faulkty ECM wouldn't harm alternator.
I don't think there is an issue with wrong alternator for the V8. The V8 was not made with the earlier VR without ACM functionality. 2005 is the year that external voltage control started

VFLXC90
Posts: 59
Joined: 21 April 2012
Year and Model: XC90 V8 2006
Location: Joliet IL.

Post by VFLXC90 »

Thanks again.
Waiting on the replacement Alt.
I'll post once I get it back together in about a week or so.
08 XC 90 V-8 157,000 Spouse
06 XC 90 V-8 141,000 Daughter
06 XC 90 V-8 234,000 Son
03 V 70 2.5 Non Turbo

VFLXC90
Posts: 59
Joined: 21 April 2012
Year and Model: XC90 V8 2006
Location: Joliet IL.

Post by VFLXC90 »

The replacement Alt. fixed my problems.
I'll post later with more detail the tools I used and tricks I learned after doing the job twice.
jimmy, thanks again for the help.

VFL
08 XC 90 V-8 157,000 Spouse
06 XC 90 V-8 141,000 Daughter
06 XC 90 V-8 234,000 Son
03 V 70 2.5 Non Turbo

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