How sensitive is it to voltage? 05 s40 2.4i alternator/battery issues?
#1
12-17-2013, 03:16 PM
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How sensitive is it to voltage? 05 s40 2.4i alternator/battery issues?
05 s40 2.4i, 149K miles.
Headlights flicker occasionally as well as the internal dome lights and the radio backlight. Very infrequently the radio will cut out.
I measured battery voltage while running and off, 14.4 and 12.5 respectively (good numbers). With the car on, turning the wheel left and right causes the battery voltage to drop momentarily (to 13.5 ish). It recovers almost instantly (1 second or so). When the voltage drops, the headlight dims.
The voltage drop on the positive from battery to alternator was about 0.05 V, voltage drop from negative battery to alternator body was about 0.02 V, both very low. Unplugging the voltage regulator on the alternator gave an immediate Red message on the dash, plugging it back in removed the fault.
The voltage regulator plug on the alternator looks like it was messed with, there are three wires coming out of the plug and all three are hooked together into a single red/white wire that goes back to the ECM. According to the wiring diagram I should only have a single wire coming out of the alternator. The part number on the alternator is for a rebuilt alternator from Denso for a 2005/2006 volvo S40 2.4i.
The flickering/cutout of the radio occurs on the highway most of the time when there is little load from power steering motor and high RPMs on engine. I am thinking the symptoms are pointing toward a failing battery due to it's inability to cover high demands without dropping voltage.
Any thoughts? I wish the car didn't have the alternator plug wires messed with but for an internally voltage regulated alternator that shouldn't matter too much, and it seems to be charging and not throwing codes.
Just how sensitive is this car? I wouldn't expect to see components turning off until the battery is down to 12V or so.
Headlights flicker occasionally as well as the internal dome lights and the radio backlight. Very infrequently the radio will cut out.
I measured battery voltage while running and off, 14.4 and 12.5 respectively (good numbers). With the car on, turning the wheel left and right causes the battery voltage to drop momentarily (to 13.5 ish). It recovers almost instantly (1 second or so). When the voltage drops, the headlight dims.
The voltage drop on the positive from battery to alternator was about 0.05 V, voltage drop from negative battery to alternator body was about 0.02 V, both very low. Unplugging the voltage regulator on the alternator gave an immediate Red message on the dash, plugging it back in removed the fault.
The voltage regulator plug on the alternator looks like it was messed with, there are three wires coming out of the plug and all three are hooked together into a single red/white wire that goes back to the ECM. According to the wiring diagram I should only have a single wire coming out of the alternator. The part number on the alternator is for a rebuilt alternator from Denso for a 2005/2006 volvo S40 2.4i.
The flickering/cutout of the radio occurs on the highway most of the time when there is little load from power steering motor and high RPMs on engine. I am thinking the symptoms are pointing toward a failing battery due to it's inability to cover high demands without dropping voltage.
Any thoughts? I wish the car didn't have the alternator plug wires messed with but for an internally voltage regulated alternator that shouldn't matter too much, and it seems to be charging and not throwing codes.
Just how sensitive is this car? I wouldn't expect to see components turning off until the battery is down to 12V or so.
#2
12-17-2013, 08:19 PM
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