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Just bought my first Volvo the other week. Had some weird things happening so I changed spark plugs then found out I had a bad coil pack and changed it out. Car was good for a few trips then I got a Power System Service Urgent with batt light. Tested battery and alternator got a weird reading from the alternator. Battery was old replaced it work fine for about 200 meters then the power system lights came back on. Replaced the alternator car worked fine for a few days. Took it in the highway and on my way back power system lights came back on. Also just before the car died the abs light came on then a message about the power steering came up and power steering died. When I got it towed I started the car and it started great then a minute or two later the power system service urgent light came back on. Any ideas on what the issue might be? Photo of dash
Last edited by TFactoR; 12-01-2018 at 10:07 PM.
Reason: Adding more information about my problem
That does happen. Might try turning off anything you can thats pulling power, lights, audio etc. Had 1 go bad about 2 weeks after replacing on a 90 maxima. Car had to run for 30 minutes and headlights on, audio, etc...the ensuing warranty "debate" is why I only go to Napa for "serious" parts. I havent tested this theory on my S40 yet. Ive done little stuff with OEM parts so far. Im going with OEM alternator on this one. Other threads mention voltage at the battery. Might check them out. So no alternator light in these? Interesting...
+1 on that it sounds like the alternator or the cables to the battery. I'd put a battery charger on it for a bit then measure the battery voltage with the engine off - should be 12.6V. Start the car and measure the battery voltage with the engine running - should be 14V give or take. Now throw on the high beams, rear defroster, AC blower etc and measure the voltage - should stay over 13V. turn off the car and feel the cables near the battery terminals - do they feel warm or show and corrosion? The fact that the car stalls suggests your system voltage is dropping below 12V when running and that messes with the computers and the car stalls. typically this is a sign of a bad alternator or a cable that has too much resistance but if your battery 5 years old, it may have a dead or weak cell.
+1 on that it sounds like the alternator or the cables to the battery. I'd put a battery charger on it for a bit then measure the battery voltage with the engine off - should be 12.6V. Start the car and measure the battery voltage with the engine running - should be 14V give or take. Now throw on the high beams, rear defroster, AC blower etc and measure the voltage - should stay over 13V. turn off the car and feel the cables near the battery terminals - do they feel warm or show and corrosion? The fact that the car stalls suggests your system voltage is dropping below 12V when running and that messes with the computers and the car stalls. typically this is a sign of a bad alternator or a cable that has too much resistance but if your battery 5 years old, it may have a dead or weak cell.
The Volvo ECM is VERY picky about the alternator. Many many "reman" units will not produce the needed output that the ECM calls for. I got lucky with an Advance Auto reman unit until it finally died after 3 years.The lifetime replacement unit I received, however, failed after one week. After much gnashing of teeth I bought a unit from Amazon that was listed as new. Although it was clearly marked as "reman" upon arrival, it has worked flawlessly.
The OEM Volvo unit from your local dealer is crazy expensive. Get your original rebuilt if you have that option.
The Volvo ECM is VERY picky about the alternator. Many many "reman" units will not produce the needed output that the ECM calls for. I got lucky with an Advance Auto reman unit until it finally died after 3 years.The lifetime replacement unit I received, however, failed after one week. After much gnashing of teeth I bought a unit from Amazon that was listed as new. Although it was clearly marked as "reman" upon arrival, it has worked flawlessly.
The OEM Volo unit from your local dealer is crazy expensive. Get your original rebuilt if you have that option.
After two alternators that tested okay. The dealer I bought it from took it to an electrical car shop. He found a cracked wire the ran in between the alternator and the AC unit. So far it's been running fine. I hope that solved the problem. I guess I see withing a week of driving it.....
Don't get too involved trying to decipher the messages that you get as the battery dies - as the voltage drops below certain thresholds, different sensors and computers will start erring out. Doesn't mean there's anything wrong with your ABS, for example.
The only realistic way to troubleshoot your car is to catch it in the act of failing. The easiest way to do that is to have a voltage monitor plugged into your cigarette lighter plug... something like this (figure $12-18 from Amazon or eBay):
Then, you need a voltmeter to see what's going wrong. If you're not comfortable probing around under the hood it's more complicated because you're going to have to get the car to your garage so they can probe around and see what's wrong.
The good news is, if the car's in "failure mode" but still running, it's not going to take too long to work out whether the following voltages are correct:
1) Sense voltage to the alternator
2) Output voltage from the alternator
3) Voltage to the battery clamp (positive)
4) Voltage at the battery positive post
5) Voltage drop from the battery negative terminal to the engine block (alternator ground) - should be a small fraction of a volt
With those five values, it should be pretty clear what's failing.
12-01-2018, 07:55 PM
2006 S40 T5 AWD Power System Service Urgent
