XC90 Voltage Regulator In-Situ Repair

Post by **simmondp** » 22 Nov 2012, 06:58

Removing the alternator is a real PITA to replace the voltage regulator, and there is just enough space with the right tools to replace it in-situ.
Attached is a PDF of how it was done!

bguzz · Post by **bguzz** » 24 Nov 2012, 07:58

Nice writeup! What caused you to have to replace yours? I thought that just replacing the regulator/brush unit isn't a long term fix because when the brushed start going the commutator is usually shot too...were you able to verify if that was still ok?

Post by **matthew1** » 24 Nov 2012, 10:06

+1

Simmondp, very nice writeup. I made your forum account MVS Contributor status.

This is scheduled for inclusion in the XC90 Repair Database.

Post by **simmondp** » 06 Dec 2012, 04:48

It's a toss up, £30 for a voltage regulator vs £300 for an exchange unit or £600 for a new part.
In the end when tried, it failed to fix the fault (it was a blown diode pack) and I ended up putting a exchange unit in.
See the next write-up!

Post by **cn90** » 15 Sep 2021, 17:46

This post is from 2012 on how to replace the VR in situ...

In order to see all the bolts and the layouts of the parts, BEST is to see how it is done with alternator on the bench.
Once you see this on-the-bench video, you will know how to do it in situ w/o the need to remove the alternator from the car...

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Hnizdo · Post by **Hnizdo** » 07 Jan 2022, 07:24

hello i would need advice on xc90 4.4 06yr. the car did not start .. The CEM exchange took place the car started without any problems. then they brought me a car with a net from not recharging the alternator. the alternator was refurbished, the flashlight was replaced, and everything worked for about a week. now I can't recharge the alternator on (engine idle 12v) .. only at higher speeds it gives 14v. thank you in advance

Hnizdo · Post by **Hnizdo** » 07 Jan 2022, 07:24

same coppy sr

Post by **ggleavitt** » 07 Jan 2022, 08:27

Maybe clarify the alternator thing- replacement with a genuine Bosch AL0821X or something else? Battery in the vehicle was fully charged when the alternator replacement occurred and is the battery in the vehicle original or has it also been replaced?

This vehicle producing any error codes? Please list them all if you can.

Hnizdo · Post by **Hnizdo** » 07 Jan 2022, 08:57

the battery is replaced with a new one, the original flashlight is die .. alt has the voltage regulator replaced with a new non-original one. and I'll try to find out about charging a new battery. the customer was already connecting the new battery

Post by **ggleavitt** » 07 Jan 2022, 10:52

Alternator output voltage goes above 13.90 VDC when you increase RPM? If you have voltages over around 14.2 you probably have a working alternator. If the alternator voltage is static at 13.90 with decent RPM, alternator has a problem. Entire alternator got replaced or just the regulator? If just regulator, what PN was used?

If you don't have VIDA on a laptop to reference, you can try this horribly clunky link for a description of the charging system-
https://workshop-manuals.com/volvo/xc90 ... _overview/