I have searched the forums, and I cannot find anything quite like what I’m having happen.

I have a 2010 S40 2.4i I bought from my parents for $300 after my last car got T boned. I like cars, Volvos are cool and I like them a lot, but my experience is with 20-30 year old V8 Lexus cars. So I’m dumbfounded. If anyone could help me I’d appreciate it greatly.

I do not have money for dealer diag currently but here’s what’s up!

occasionally, the automatic locks will not work, the keyless system will not work, the alarm goes off if I get the door open, the windows will not roll up and down correctly, the dash display does not turn on the first time that I turn the key, and I get two warnings, one of them telling me that the SRS system needs urgent service and the other saying that my tire pressure monitoring system is malfunctioning.

My very unprofessional theory is as follows; the battery is either old and quickly losing voltage or the battery has a bad cell, causing the ECU not to get enough voltage and the car freaks out?

Or, have I bought a possessed vehicle?

 

When you have several seemingly unrelated errors popping up at once, it's almost always a power supply problem. That normally means battery or alternator.

You might not have the funds for a stealership trip, but I'm betting you can afford a Harbor Freight multimeter (they have coupons for free ones fairly often - otherwise, $5-10 for a meter that will do nearly anything you need it to on your car).

Check the battery with the car not running. If it's well under 12 volts, it's probably bad - but check it again 10 minutes after driving it for 10-20 minutes (or charging it for a few hours, or overnight with a low-current charger). If it's still under 12 volts, it's probably bad (check the date code - if the battery is over three years old, it's really likely). Then, with the car running, check the voltage - it should be around 14 volts. If it's much less than that, the alternator isn't working right.

 

My S40 just died...2005. Been raining...something electrical..I cannot tell.

 

Chances are the wet weather created a short and drained your battery.

A few basic questions - did you try and jump start it? Once you connect the jumper cables, give the running car a few minutes to put a base charge into the battery.

Did you measure the voltage across the battery terminals? A battery at 80% charge should measure at 12.6V. Anything below 12.2 suggests the battery is drained or needs replacing.

If you get the car to run with a jump, with the car running and after you disconnect the jumpers, measure the voltage across the battery - should be in the 14V range. if in the 13s let it idle for a few minutes to see if it builds up. If not you may have an alternator issue. Finally, what condition are the battery terminals and big power cables in? if the cables are swollen and crunchy, they have corrosion inside the insulation. If the the insulation is bubbled and melted in spots, they have corrosion and need to be replaced. If the terminals to the battery have corrosion and salt deposits, they need to be popped off and clean the cable terminals and battery posts with a wire brush (I also have used naval jelly and similar solvents to get the corrosion off old terminals) and then reinstalled and tighten properly.

If the car won't start with a jump, check fuses. Your owners manual will show which fuses are where. Owners manuals can also be found online free from Volvo. just google "volvo owners manuals" Don't go to an ad riddled site that wants to charge you for the booklet.

 

Yes it turned out to be the battery...now I just have to assemble the CEM back into the car......GOSH !

 

Again...are the Haynes book advice correct when restarting the Volvo S40 after battery disconnect ?

 

I'm curious - what does Haynes suggest? Is it something like locking/unlocking with the fob to reset the immobilizer? Some cars also recommend a driving cycle to help the ECU relearn, typically taking a 30 minute drive over varied speeds will take care of that.

 

I recall it says to keep the key at position 2 for a minute before going into position 3...as the computer checks everything by it self when alerted...sorta.

 

No...it says keep it at position II for ten secends..then cut it and then start like normally !

Idle first to warm it then to 1500 rpm...and back to idle.

 

good to know, thanks for the share.

 

I cleaned a register plate light...not broken but sems to cause no electricity to pulp.

I wonder if that caused the battery to empty itself ?

 

Doubtful that's your problem. An open circuit (no connection) draws no current at all, ever.

A shorted light socket would blow the fuse immediately, so that's not likely either.

It's really just a matter of hooking up an ammeter in line between your battery and battery cable, and pulling fuses until you find the one that kills the current drain... then tracing that circuit down to figure out the guilty component.