Short Version:

A new voltage regulator on my 01 V70 solved many other problems I was having. It's very important, especially in these cars, to have a good battery and Generator/Regulator.

Long Version:

Last night I changed my voltage regulator because of an error message telling me I had a "Over Voltage" problem, in addition to the system only putting out between 11.5V to 12V. After testing, I realized I had more of a problem then I thought.

Since I bought the car in June '08 I've been having various electrical problems that I really didn't know were all associated with this one issue. Thanks to tech and the other posters on here, I started realizing how sophisticated the Volvo's are technologically speaking.

Tech says there are 17 different computers/cpu's in the V70. The car is all networked together electrically like a computer network. If one part of that network isn't working, it takes from the other part to compensate. When you don't have enough power going to all parts of it as a whole, it apparently doesn't like that very much.

I'll explain.

I did major at one time in electronics engineering but didn't realize this car was so sophisticated, hence I assume is why they are priced as they are. I drove it about 50 to 75 miles today with the new regulator and a fully charged (2 month old) battery. I'm going to list the electrical and mechanical problems I had which have all fixed themselves.

A) Passenger side air vent servo making constant noise while braking (and sometimes while cruising), as if it was trying to open and close over and over and over again or getting stuck while in the cold position (this is the first problem I believe I ever posted about on this forum). This no longer happens.

B) When you turned the blower off, it would never go off completely, but stay in almost the lowest possible speed setting. You had to keep turning the **** on and off to get it to finally kick off. I thought this was a mechanical problem as well with the switch since it appeared turning it hard to the left got it to work. Guess what? It works fine today for the first time since I bought the car.

C) Dome lights flickering sporadically when turned on. This still occurs but almost impossible to notice unless you really stare at it, but at the norm with other cars.

D) Headlights dimming every time you come to a stop (relating to the later-mentioned idling issue). This doesn't happen anymore either.

E) The HomeLink system (I think that's what it's called) would only work after the car had been running for a few minutes, especially in the cold. It seemed like the lights were really faint or dim as if it never had enough juice to send out a signal. This now works the instant the car is started, which it didn't do before the change. I thought maybe this was normal? I didn't know.

F) The AC never seemed to work properly (as I posted previously) Perhaps there was such strain on the Alternator that the compressor just wasnt getting what it needed? I dunno. Changing the filter helped, but today, the AC is working much better then it ever has, even at idle, and it really struggled at idle before.

G) Although minor, the outside temperature reading was always 3 degrees colder or warmer the it really was as compared to the national weather service. Today, it was right on the money the entire time we drove the car and during a variance of about 10 to 15 degrees from the time we left to the time we came back. It must have been getting false readings due to the electrical reading not being correct. I'm only assuming again.

H) The transmission always had quircky issues like varying shift points (even with the same driving patterns), taking a while to figure out where it should be, etc. I fixed I would say 75% of that with fluid changes and additives and so forth, but didn't realize until this morning how smooth this car was supposed to shift. It's a whole different experience now. It's definitely more predictable and constant. Perhaps the computer for the trans wasn't operating properly.


I) Perhaps the largest problem to date; while coming to a stop, the engine falls below idle speed, almost to 500 rpms, and then comes back up to 700 - 800 right at the point where you come to a complete stop, then sometimes had issues figuring out where it was supposed to be. Thinking this was a mechanical problem, I had rebuilt the entire air intake assembly, bought a new filter, taken apart and cleaned the throttle body and MAF, etc, because I thought this problem was due to lack of air. This solved SOME of the problem, but it still existed. After a while, I figured maybe it's just the way the car is, that is does that normally. I thought perhaps I was loosing compression, I had a system leak or bad piston rings or head gaskets, tried new oils, additives, thought maybe my trans was sticking, etc. All of the causes that might cause the engine idle to go way down and bounce back I fixed, and as of yesterday, it was still doing it. I also put brand new iridium spark plugs in, thinking maybe the plugs were bad. I also replaced all pulleys and belts, etc. The car doesn't do this anymore, now that it has the proper power and voltage I'm assuming.

The way tech explained the system to me is this; the reason there are so many computers in the car is because they monitor everything, right down to the power windows and dome lights. When one system is lacking in power, it borrows from another system. It does this so fast that it's undetectable to you and I.

Tech (Alan) used this example; if you are putting down your window and say, your AC compressor kicks in, or your cooling fan, etc., and it doesn't have the right amount of power to initiate properly, the system will automatically borrow the power from something that is not engine critical, like your power windows, and re-route that to your engine component that needs it, then once it's operating at normal parameters, it gives back or released that borrowing of power to the original device. Apparently this happens at lightning-fast speed so you don't even detect it while it's going on, it just happens. Now since I am IT guy by trade, we all know that the amount of processing power to be able to do something like that quickly is pretty substantial considering how many different computers this car has, so these computers have to be running very fast and accurately, something that is near impossible without a constant and accurate voltage supply.

If you are only putting out 11.5 to 12V from your Alternator/Generator, you are barely putting enough out to keep the car running normally, let alone keeping the battery charged. It should be between 13.5 to 14 on these cars (don't quote me on that, but that's what I've been told and found on the web) as with most cars. If you are running 1V to 2V under, what do you think the computers are going to do? They are going to try to borrow power from the other systems that aren't engine-critical, hence ALL of the above-mentioned electrical problems I had. It seems like what the car was doing was constantly trying to borrow power from everything else to make sure the engine was running, but at times of low idle, it was so thirsty for power from the Alternator, it couldn't take it and that's why I believe the Alternator was being bogged down while the engine was about to go to idle, because it couldn't handle all of the power requirements it needed to function, so it just went crazy. I think the faulty regulator was telling the computers and Alternator hey, you need to work harder because this isn't working out. I think my car has been starving for more power for 9 months.

Now I'm basing this all on the facts of electrical theory and so forth. The FACT that all of my prior electrical problems are gone seem to make this theory make sense, but I'm by no means an expert. I just know enough to seem to make myself make sense.

So in conclusion (if anybody even made it this far), after 9 months of struggling with this car and constant troubleshooting and repairs, I think I can say that for once, there is nothing wrong with my car and I don't need to fix anything. For a while, it was always fix this and move on to the next. I never had it to the point where it just all worked. The suspension is fixed, it's running great, it shifts great, etc. I learned more about cars in 9 months then I learned collectively my entire life.

ALL of this because of a $100 Voltage Regulator that took a couple of hours to fix, which should take about an hour if you know what your doing already.

I'm still in shock.

 

Glad all is good now!!!

 

It's still putting out around 14.05 to 14.10 on the terminal in the engine compartment so I think everything is good.

 

Dear Hummer guy & tech-

I have all of the above problems with my 1999 S70. For the last 2 years I've been driving around with no AC...actually the clutch on the compressor was not engaging (cold air would stop blowing). The low idle coming to a stop is a recent phenomena and usually only occured when I had the AC on. The AC would work if you turned it off and then back on after a few minutes, but it would always lead to warm air.

So I got the opinion of a very good volvo mechanic (who is now 75 miles from me and had worked on my car for the previous owner and me) and was told the clutch is probably sticking on the compressor. Long story short I got it fixed at a reputable shop in my new location. Turns out, the shop owner tells me, that the voltage to the clutch was dropping as it disengaged. Plus he added it was rusty and you could tap it to get it to engage, etc.

I leave his shop ($1,000 later due to 4.3 hours of labor and all new compressor/clutch, dryer, etc.), load up the family to head out for a long weekend (since the air finally worked) and the alternator goes out on the highway (lights flickered on & off in wierd order, such as battery, brake, ABS...then speedometer went out, odometer cleared). A different mechanic at the station I was lucky to pull into said they may have shorted the alternator if they did not disconnect the battery, etc.

Well the alternator is right above the AC compressor, so I figured they had to take the alternator off to get to the compressor assembly. The mechanic (great guy, been working on foreign cars for over 20 years) said he just wiggled it out below the alternator and put the new one in (4.2 hours!?).

Back to the alternator. Had the car towed back to the shop. We all suspected alternator as the battery was totally dead. I asked the shop owner to be honest with me and actually check the alternator, etc. and man up if they made a mistake. He just reported back that the alternator was bad and no wires were crimped on it. Then said that will be another 2.1 hours to replace with a $350 rebuilt Bosch alternator. I've done these on other cars in the past, but would not attempt since it is volvo.

So I guess my question is could it be my voltage regulator causing me all the problems?

I pulled the codes off the car last year and 3 errors came up including thermostat and 02 sensor. The mechanic now says only the 02 sensor is showing. He does not even won't to give me a break and replace the sensor during the 6+ hours he's had his guys replace two parts.

Would a voltage regulator register with a code?

Thanks for this great forum. I hope you guys can send me an answer because I suspect that when I pick up the car tomm., turn on the AC and come to a stop, the car will drop down to under 500 idle and then back up to 750 or so. I told the shop owner this happened right after the AC repair before the alternator went out but he did not want to listen to any of my comments or diagnosis....just more money, more money...hehehe

 

Yes it can be the regulator only on that one.

As for the Idle dip I will bet if the throttle body is cleaned it will idle great when coming to a stop.

It is common for a dirty throttle body to cause the idle dip.

The low voltage will not throw the O2 sensor code.

 

Tech-

Is the "dirty" throttle body covered under the 1999 s70 recall?

Volvo of NA already reprogrammed the throttle body at a volvo dealer a few years back under the recall.

Should I get this tuned up regardless? Will my car limp into home mode or something if I don't address the throtle issue soon?

Thanks.

 

This reminds me, sort of, of an afternoon spent at my buddy's house where there may have been a few brews consumed. His son was a high school junior and a budding high school journalist. Somehow, the two of us concocted an idea for his high school paper. "Junker of the Week" or something like that. Being in high school, there was no shortage of material to write about.

 

For one thing,you need to check the voltage when the engine is off,not when the alternator is raising system voltage to its normal level.You can test for proper cranking voltage with a voltmeter.The several hundred amperes of current the starter motor draws should pull the battery voltage down to a normal 9 to 10 volts.

 

Looks good. However, change the background color from yellow to pink or purple..

 

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Thanks for this great forum. I hope you guys can send me an answer because I suspect that when I pick up the car tomm., turn on the AC and come to a stop, the car will drop down to under 500 idle and then back up to 750 or so. I told the shop owner this happened right after the AC repair before the alternator went out but he did not want to listen to any of my comments or diagnosis....just more money, more money...hehehe

 

All of the causes that might cause the engine idle to go way down and bounce back I fixed, and as of yesterday, it was still doing it. I also put brand new iridium spark plugs in, thinking maybe the plugs were bad. I also replaced all pulleys and belts, etc. The car doesn't do this anymore, now that it has the proper power and voltage I'm assuming

 

Can anybody say with certainty that if the voltage regulator puts out 1 less volt it will drop the voltage output of the blue wire (collector) on the coil/DC power stage?

 

Thanks for this thread.

 

Autozone will load test your system. With the engine running, the load test will simulate a starter load and shows how quickly your charging system will recover, testing regulator, brushes, etc. Harbour Freight sells a load tester that puts about 100 amp load (toaster wire) and the voltmeter will show how quickly your system recovers.

If the system takes a while to recover (minute or so is normal but any more will mean more attention is needed). I have discovered a bad regulator after replacing what I thought was a bad battery.

happy new year

 

ELECTRICAL ISSUE ONLY

After reading your dilemma, I needed to write this little note. I would like to express my gratitude for ANY info/suggestion you may have. MANY members within 3 forums and other overseas forums have drawn a blank over my Electrical problem. I have been working on my Volvo 850 turbo on and off for OVER two years and have changed / swapped / troubleshot many items as you have done. My distinct advantage, is that I have a duplicate car/engine available to me. I have a 94 850 turbo 5234T station wagon and a 96 850 turbo 5234T sedan, the same engine. There are minor differences (EGR) between the cars, but they are ideally the same. I have reached the level of tearing into the connector that goes to the engine control module. My car starts perfectly and runs perfectly for approximately 18 seconds and then stalls. I do not have multiple electrical problems that you had on your vehicle. I have never had any OBDII codes, all components and indicator lights are responding correctly, but it still dies. Swapped /changed / Replaced: ECM, MAF, CPS, RPM, TPS, Coolant sensor, Fuses, Overload relays, ignition switch, battery, DI power stage, coil assy and the problem is EXACTLY the same. The problem has never changed in any way. Gave a serious examination of my pos lead to battery/alternator. My bottom line: The yellow/white wire that is an output signal from the ECM connector B11 becomes an input signal for the coil connector (now a Blue wire) to the base of a transistor of the DI power stage. If I compare my '94' to my '96' voltage, I can definitely see the problem.

When I start my '96', I read 13 Volt on the red wire (coil) during startup, running and into the stall. However, on the blue wire (coil) I get: 10V on the startup, about 1/2 second later, I get 11V and about 7 seconds later I get 5.5 volts, and during the stall I get .7-1.3 Volts. My '94' Volvo RED wire (coil) reads, 14.4V on the start and the run. The '94' BLUE wire (here is the BIG difference) reads 13.4 V on the start and run. The blue wire (according to the Volvo schematic) is part of the secondary winding to the collector and then the emitter to ground. A y/w wire from the ECM connector B11, to pin 4 on the connector to the coil, supplies voltage (???what value???) to the base of the transistor. I tried an in-line 5A fuse from the pos lead of the battery to the red wire of the coil....hoping that adding (if possible) EXTRA voltage would provide a stable voltage to the blue wire....this did nothing, the vehicle still stalled as usual. I tried the same on the Neg lead of the battery......fuse died instantly. I tried the battery draining procedure.....pulled out each fuse one by one and found 168 milli volts everywhere. Even the alternator passed the tests at a (Auto Zone) parts store. I got a paper read-out and it shows that the alternator is within specs. I have researched voltage regulators for my Alternator till the cows come home. I would recommend that if you want to save 60% on Voltage regulators that you order them from England. Believe me, I can tell you where each wire to each connector goes. I have put in so much research, that I have helped many people with their Volvo problems, but my own is illusive to say the least. I can even tell you that the CPS,TPS and coolant sensor tie in together at pin #1. I took my '94' failed smog test (685 Nox reading down to 3) basically took apart components that most people would say "just buy a new one". I do not have a scope and do not trust my DMM Fluke 83II in the frequency mode to help me check the CPS for a signal. Any suggestions you can provide will be helpful.

pgu44

 

FIRST AND ALWAYS check your fuses. Both under hood and dash ! I can't tell you how many problems I have solved with a $.75 fuse. Check all of them. Won't take you 5 minutes and could save you thousands of rip-off dollars at dealerships.

 

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My s70 is putting out 18 volts and over heating the positive charged wire connecting to the battery. I recently replaced the alternator and the problem resurfaced after one day. Any ideas about what might be going on?
I'm about to replace the alternator for a second time.