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mfrance388

Electrical Issue, Please help.

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I have what I believe is an electrical issue that is getting worse and now has become a safety concern and would greatly appreciate any help.

I bought a 2005 Mercury Sable GS with a 3.0L V6 with 139K miles and for the first three weeks everything was great. 

I got home from work, shut the car off and the gauge needles started to shutter rapidly.  When I turned the key to start the car nothing happened.  After about 30 secs the shuttering stopped and everything was back to normal.  This now happens quite often.  Now something else.  While driving, the ABS and Brake lights come on, the gauge needles all drop to zero and the there is a short, quick loss of power but everything comes back on.  Now this can happen an you lose all power.  The car shuts off and you have to hopefully coast somewhere safe and try to start the car.  Hence the safety concern. 

I know electrical issues are sometimes hard to diagnose.  I'm just hoping someone has heard of something like this before and can point me in the right direction.  If more information is needed just let me know and I'll list it.

This is a beautiful car that has no other issues.

Thank you for your time and help.

Mike

 

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This happened to me a while back. You are having a voltage drop issue which is causing everything to lose power for a fraction of a second. Have your battery load tested, it might be dying or have a bad cell. Have the alternator checked as well.

You can check on your own without load testing if you want, but the results might not be as conclusive. Check the voltage at the battery and alternator with a voltmeter with the engine running. The battery should be over 12 volts and the alt should produce more than 13 (typically a little over 14). Turn the engine off, then press and hold the RESET button on the dash. While holding it down start the car. Keep holding the RESET button until ENGINEERING TEST MODE shows up on the little data center. Release the RESET button and start pressing it repeatedly until you get the readout for battery voltage. If you pass it just keep pressing it until you come back to it. If the voltage at the display is lower than the voltage at the battery you probably have a bad battery. This was my problem for a while. The battery always checked out but the gauge cluster said it was getting less than 12 volts. Tested the cells on the battery and one of them was bad. Went through a couple alternators trying to fix the issue. The Taurus and Sable became quite sensitive to voltage fluctuations when Ford introduced the CANbus system into these cars in '03-'04.

Edited by Angrod

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Thank you for the information. I have done everything you suggested and here are the results.

At Autozone the batt, alt and starter all passed.  Using a volt meter at home I double checked all but the starter. Batt and alt checked out.

Then I put the car in Eng Test Mode.  With everything off the batt showed between 14.1-14.3.  I turned on the AC, Max, the reading changed to 14.0-14.2.  Turned on the radio and reading stayed the same.  Pushed on the brake peddle and it dropped to 13.9.  Took foot off brake turned on rear defroster it changed to 13.5.

The other thing I noticed were DTC codes that I’m having trouble finding the meaning of.  E203 and $9208.  

I drove the car while watching the battery voltage. With radio and AC on the voltage was 14.0-14.3.  Until I put the brakes on and it dropped just under 14.  Same with defroster on.

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18 minutes ago, mfrance388 said:

Thank you for the information. I have done everything you suggested and here are the results.

At Autozone the batt, alt and starter all passed.  Using a volt meter at home I double checked all but the starter. Batt and alt checked out.

Then I put the car in Eng Test Mode.  With everything off the batt showed between 14.1-14.3.  I turned on the AC, Max, the reading changed to 14.0-14.2.  Turned on the radio and reading stayed the same.  Pushed on the brake peddle and it dropped to 13.9.  Took foot off brake turned on rear defroster it changed to 13.5.

The other thing I noticed were DTC codes that I’m having trouble finding the meaning of.  E203 and $9208.  

I drove the car while watching the battery voltage. With radio and AC on the voltage was 14.0-14.3.  Until I put the brakes on and it dropped just under 14.  Same with defroster on.

Volts seem good. I would redo the grounds as a routine maint. See pic, this is the ground strap from the engine to the body at the cowl, PCM ground below and corroded. Note, they bolt the power strap over paint, and it corrodes. I sanded the paint off, scrubbed the corrosion off the terminals and put electric joint compound on them. Fixed an wandering idle speed. The TPS showed erratic volts on the ground/return post. It goes direct back to the terminal in the picture. Engine off it was steady, once started the ground terminal had variable volts vs the body.

-chart-

GroundTavWh.jpg

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Going to check all grounds I can find.

Thank you for your help.  Will let you know how it turns out.

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Well I cleaned up the grounds you mentioned and a few others.  Now when I run the cars Eng Test Mode I get 4.3 - 4.5 volts even with the AC on MAX.  When I turn on other items, radio, rear defroster, etc. the voltage stays above 4.2.  So, I'm seeing a .2 to .3 increase with everything off and up to a .6 increase with items on.  I'm going to stop and just drive it and see what happens.  I will continue to run the tests.  But would like to see if this was for sure this fix.

I can't thank you guys enough for your help.  Never had this type of problem and need the help. 

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