Son was on his way to work this morning in the '09 XC90. He called to state that he had "broken down" and there was a message "POWER SYSTEM SERVICE URGENT" on the dash.
I drove to his location and scanned the codes. P062001 Generator control circuit, General electrical fault and P062074 Generator control circuit, Mechanical faults, Actuator slipping. Battery was reading about 8.5V, car would not start. Drove home and got the battery out of my '79 300SD (conveniently it's the same size), went back to the Volvo and changed it out. Car started and ran fine, no fault messages. I drove it home and on the way there was a sudden screeching noise under the hood and the same fault message appeared. That continued for about 20 seconds and then stopped. The message stayed on. The alternator control module (ACM) sends the engine control module (ECM) information on a mechanical fault in the alternator (engine speed exceeds a certain value but the alternator is not operating). Turns out the alternator on this car is not directly belt driven, it's driven by a coupling off the back of a pulley on the serpentine belt path. From what I've read online[1], there is a bolt in that coupling that can back out and then it will slip. So this sounds like what is happening. To get at the alternator and coupling, the intake manifold has to come off. So I'm going to look into that job. Sounds like it might be a bit of a PITA. Suppose I should just go ahead and replace the alternator prememptively while I'm in there? The car has 194k miles and I have all the maintenance history from prior owner and no record of the alternator being replaced. [1] https://www.swedespeed.com/threads/power-system-service-urgent-questions-p062001-p062074-codes.614113/post-7589041 _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
