Alt output 15v,too much?

[Gyro]

My 06 had the abs,tc and esp/bas lights come on with chime,and lost throttle response.
Pulled into a parking lot did a couple figure 8's and throttle response returned but lights stayed on.
Drove it a few kms,parked it and it sat for 1/2hr,
Started it back up and no lights,everything back to normal.
Check for codes, got p0562 low system voltage.
Battery reads 12v while off and 15v at idle.Is 15v too much?
Had battery load tested, only 654 of 690cca.it is 23 months old.Napa will replace free.

Thoughts?

Gyro

 

[uss2defiant]

It's a tad high.
What's the spec of the alternator?

Typically lead acid batteries are charged max at 14.4V

 

[tjkj2002]

Yeah 15v is way to much,14.9v is max.The voltage regulator is located in the PCM,not the alternator.

 

[Gyro]

So a new pcm is in order?

Gyro

 

[CactusJacked]

Battery reads 12v while off and 15v at idle.Is 15v too much?
Had battery load tested, only 654 of 690cca.it is 23 months old.Napa will replace free.
Thoughts?
Gyro

You didn't say, but were you checking with a volt meter, or going by the (less accurate) dash gauge?

 

[Gyro]

DMM

Gyro

 

[LibertyTC]

Ensure the battery contacts have zero corrosion are spotlessly clean & tight!
If it is consistently running at 15 Volts, I would wonder whats up. Mine has hit 15v for a second then backs off to 14.9 to 14.7 normally.
I am reading my voltage through OBD2 port /Autel gauge reader. Some variances are possible on different external Digital meters.
The KJ should throw an Alt light though if something is really wrong my guess.
Alternatively many shops can test the charging system including a voltage & diodes & loaded amp output check.
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Snap On has some pretty nice equipment out there!

 

[Billwill]

The PCM reads the voltage somewhere....usually near the ignition switch but I am not sure about the 2006 model. The PCM then adjusts the voltage pulse going to the field coil inside the alternator to raise or lower the voltage.

The fact that the PCM complains about a low voltage and tries to up the voltage by going all the way up to 15 volts seems to me that there is a voltage drop somewhere.

I would check that the battery connections are clean and tight, the negative lead going to the chassis is clean and tight and the grounding strap grounding the engine to the chassis is clean and tight on both ends.

Give that a try and lets see what happens.

 

[Gyro]

Had the battery on charge overnight and 12.12v is the DMM reading this morning.
Going to replace battery,clear code and see what happens.
I have been driving it since with no problems.
I''ll check the grounding straps,the battery terminals are clean, tight and greased.

Gyro

 

[Gyro]

Replaced battery,12.74v engine off,14.75v at idle.low system voltage code gone on it's own.
I'll put a few drive cycles on it and see how it goes.

Gyro

 

[LibertyTC]

That is strange that the old battery would pass a load test and yet the volts were still quite low in the AM even after charging.
I wonder if a hydrometer test on each cell may have shown a bad cell?