Am here seeking advice where to look first or second. 2003 XC70 drove to the store car ran great. Came out started it and the radio went off,air con stopped, lights locks windows all no go. many warning lights. It ran so I drove it home but it didn't have a lot of power. Had been running great since I changed some relays and the alternator. The battery had been fully discharged a number of times before I put in the new alternator. (I suspect there was a phantom draw from voltage regulator.) Thanks a lot for any advice or links. I sincerely appreciate it.

 

sounds like the car went into limp mode - which can also happen when the system voltage drops below 12.6 V. If you can start the car up, test to see if your charging system (and battery) is maintaining about 14V when running. Also check all the fuses.

 

Thanks so much for describing a "limp mode". Makes it sound curable.

I unhooked battery to "start over" and haven't hooked it back up yet... Was thinking of pulling battery to charge first ....or not do you think. Haven't restarted. Will check battery before I lift it out (leaning over from inside car doors locked) . If it's low I I should probably not use it for troubleshooting... eh? Just get another one. Three year old battery but fully discharged numerous occasions before and after I owned this car...part of the "good deal" Thanks for responding. Could that battery finally decayed enough to have triggered this? No early warning system error light.

One more thing ...what about with the air-con on high already, left on when I shut the car off, , (which I never recall leaving it on before) the stereo up high, phone charger, maybe my foot on the brake, and driving lights all when started hit that system hard enough to funk in this direction with a decayed battery?

Appreciate your help. Get you a "big purple drink" when you come to Mardi Gras!

 

Most of the time, when this happens, it's because the body/accessory contacts on the ignition switch didn't make up. The a/c, radio, etc etc. all go dead every day when starting, but the spark plugs don't. So having one circuit broken and the other not is actually a normal state of the ignition switch. So wiggling the switch a bit is the normal first response.

In your normal life history, you never saw this, because the spring in the ignition switch pushes the switch back just-so-perfectly when you let go of it. But sometimes things don't happen perfectly when a car gets old.

 

Checked all the fuses went and bought a new battery. old one was low voltage 8.6... Hooked fresh battery up. Everything worked after using the power lock button a few times. All warning lights off then after a few minutes of running fine battery warning light came on and EL. POWERSYSTEM SERVICE REQUIRED message displayed. Warning light and error message both would go out when I revved it up, but both came back on at idle. After a while it took an even higher idle. Unhooked battery overnight am going out again and will measure at battery when I have an assistant to operate throttle. I'll wiggle the switch. I'll wiggle those computer boards first too.