Hi,

My 94 Volvo 850 n/a has recently developed a rough idle and it will stall occasionally. It will stall either while idling, or when driving at lower speeds.

So while checking for the ususal suspects I pulled the codes for the fuel system, and I got code 1-3-2 (Battery voltage too low or too high). This led me to checking the battery and the alternator and it turns out that the output from the alternator is way too high, in the 16.8 range.

So would this cause the engine to run rough and stall? Or is this a separate issue?

 

Yes, it would. That kind of voltage could cause the ECU to read sensor incorrectly and even overload the system all together.

 

Thanks for your reply. I pulled the alternator and will take it to have it tested out of the car tomorrow, and if it is indeed faulty, I'll get a new one, so hopefully that will take care of my problems.

Any chance the high voltage have caused permanent damage to any sensors or the ECU?

 

It's possible, but hopefully you will be alright. The voltage regulator part of the alt is usually replaceable separately; it's integrated into the brush holder. But replacing the whole alt would be safer; esp if you don't have the means to ck out the windings and such..

 

So I got a rebuilt alternator and put it in today. I did consider getting just the regulator, but I figured I might as well just replace the whole thing while I'm at it.

Anyway, the stalling problem seems to have gone away, but it's a little early to conclude since it was an intermittent problem. Looks like gas mileage went back up a bit so that's a good sign at least.

Thanks for your help guys!

 

Just wanted to give a quick update on this one. The new alternator did not solve my stalling issue, so my car stalled again and wouldn't start at all. Ended up having to call a tow truck to get it home.

The good news however is that in replacing the alternator the code for too high voltage went away, and the code for the camshaft position sensor started showing up. So I replaced the sensor and now the car seems to be running fine.