1998 Pontiac Grand Prix PO560

Tiny
LLREPAIR0247
  • MEMBER
  • 1998 PONTIAC GRAND PRIX
  • 3.1L
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 176,000 MILES
17.6 with koer voltage on orange wire at alternator with koeo is 10.65 tried a different alternator and a different reflashed pcm
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Friday, November 6th, 2015 AT 8:07 AM

18 Replies

Tiny
WRENCHTECH
  • EXPERT
You appear to have a bad battery. The koeo voltage should not drop that dramatically. A bad battery can make the alternator do strange things also so I would replace the battery and check your voltages again.
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Friday, November 6th, 2015 AT 8:41 AM
Tiny
LLREPAIR0247
  • MEMBER
The battery is new battery voltage with engine off is 12.3 why does my orange wire at the alternator only have 10.65 this should also have12.3 right?
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Friday, November 6th, 2015 AT 8:53 AM
Tiny
WRENCHTECH
  • EXPERT
Yes, it should. There is a fusible link between the alternator and the battery that may be bad or you may just have a bad connection somewhere.
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Friday, November 6th, 2015 AT 8:55 AM
Tiny
LLREPAIR0247
  • MEMBER
Where is the fusible link should I run a new wire from the sense fuse to the alt.
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Friday, November 6th, 2015 AT 8:58 AM
Tiny
WRENCHTECH
  • EXPERT
Sense fuse? I though you were reading the output terminal.
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Friday, November 6th, 2015 AT 9:03 AM
Tiny
LLREPAIR0247
  • MEMBER
The voltage at the sense fuse is 12.3 and the voltage at the orange wire at the alternator is 10.65
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Friday, November 6th, 2015 AT 9:22 AM
Tiny
WRENCHTECH
  • EXPERT
I don't know what color the wires are. If the main terminal doesn't match battery voltage, you have a problem in that circuit. The fusible link is probably at the starter.
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Friday, November 6th, 2015 AT 9:34 AM
Tiny
LLREPAIR0247
  • MEMBER
U are telling me info I already know I need help finding the problem can u look at a wiring diagram and give me some good info if u need more info on my end just ask
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Friday, November 6th, 2015 AT 9:43 AM
Tiny
WRENCHTECH
  • EXPERT
Check for the following conditions:

Poor connection or damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the Ignition 1 voltage display on the scan tool while moving connectors and wiring related to the PCM, dash harness, and engine harness. A change in the display will indicate the location of the fault.

If DTC P0506 cannot be duplicated, reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

https://www.2carpros.com/images/external/62533027.jpg.gif

The orange wire runs from the fuse box to the PCM and the code is telling you the voltage is incorrect.
Find out why. Does the fuse match the battery voltage? Maybe an issue with the fuse box or wiring.
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Friday, November 6th, 2015 AT 9:53 AM
Tiny
LLREPAIR0247
  • MEMBER
The fuse voltage is correct and the #20 orange wire at the pcm has the correct voltage I don't understand where the orange wire at the alternator gets its voltage --if I unhook that orange wire at the alternator my engine running voltage falls into spec
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Friday, November 6th, 2015 AT 10:21 AM
Tiny
LLREPAIR0247
  • MEMBER
Should the orange wire at the alternator be hot at all times when I turn the key off I lose voltage at orange wire at the alternator but it stays hot at the -pcm when I unhook the orange wire at the alternator and jump to b+ everything works normal
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Friday, November 6th, 2015 AT 10:31 AM
Tiny
WRENCHTECH
  • EXPERT
The orange wire at the alternator should be hot at all times. It is powered by fuse #10
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Friday, November 6th, 2015 AT 11:00 AM
Tiny
LLREPAIR0247
  • MEMBER
Be back on Monday am will text more info then thanx for all the help
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Friday, November 6th, 2015 AT 11:21 AM
Tiny
WRENCHTECH
  • EXPERT
You should be able to resolve it with the info you have.
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Friday, November 6th, 2015 AT 11:33 AM
Tiny
LLREPAIR0247
  • MEMBER
There is no fuse #10
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Monday, November 9th, 2015 AT 7:25 AM
Tiny
WRENCHTECH
  • EXPERT
According to the wiring diagram, it should be hot at all times.

https://www.2carpros.com/images/external/78916039.jpg.gif
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Monday, November 9th, 2015 AT 7:44 AM
Tiny
LLREPAIR0247
  • MEMBER
The ecm sense fuse is hot at all times with correct voltage with key on voltage at orange wire at alternator is only 10.65 with key off it goes to 0
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Monday, November 9th, 2015 AT 9:09 AM
Tiny
WRENCHTECH
  • EXPERT
The first diagram was for a Grand am not Grand prix but here is the correct one and that feed is the same. That fuse should be hot at all times.

https://www.2carpros.com/images/external/78916033.jpg.gif
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Monday, November 9th, 2015 AT 9:16 AM

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