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Pulled fault codes this morning...any ideas

Discussion in 'Dakota, 1998-2013 Durango and Aspen' started by Peymack91, Sep 6, 2016.

  1. Peymack91

    Peymack91 Member

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    My "check engine" light is on so I pulled the codes on my '91, 3.9, auto. Dakota. Came up with:
    12: low battery
    36: different definitions
    37: solenoid coil circuit
    41: alternator field circuit open (?)

    I know that my ammeter gauge is registering just above the second hash mark (where 12v would be) At one point, it was halfway up the gauge (around 14-15v), even at idle with AC and headlights on.
    What should I be looking at with those codes?
    I do NOT want to get stranded with a bad alternator/dead battery.
     
  2. valiant67

    valiant67 Rich Corinthian Leather
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    Code 12 does not mean a low battery. It means power has been interrupted to the computer. However, it often is present when that has not occurred and is better looked at to mean "start of codes".
    At this point, the best thing is to have the charging system (battery and alternator) tested. 12V is low, it should be around 14V.
     
    floridaman2013 and Doug D like this.
  3. Peymack91

    Peymack91 Member

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    I just had the alternator tested and it came back as working just fine. Putting out 14.5v to be precise. Battery WAS low, as I had it tested and charged at the same time the alternator was tested. I'm not used to this truck and no other vehicle I've had did this with a low battery (or a battery on its way out). Is this typically what happens with a dying battery in these cars; the ammeter reads lower and lower?
     
  4. Doug D

    Doug D Virginia Gentleman

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    Are you sure it's not a voltage gauge? I haven't seen an ammeter gauge as a factory gauge in decades. A good battery should read 12.6 volts at rest (engine and all accessories off) and ~14.4 volts with the engine running. A battery has 6 cells with each cell holding 2.1 volts. 2.1 x 6 = 12.6 volts.

    However, a battery could read "good" with 12.6 volts, but fail a "load" test. Batteries do eventually die. Heat is the primary killer, but the symptoms don't usually show up until colder weather when the extra cold cranking amps are needed to turn a cold engine. The test should have indicated what the cold cranking amps measurement. If it's significantly lower than the CCA rating of the battery, the battery is probably on its way out. How old is the battery? Typically they last 5-6 years (longer if you are lucky or shorter if you reside in a very hot climate).

    The original battery (MoPar) in my '06 Ram 1500 was still going strong at the 6 year mark (2012). I preemptively replaced it with another MoPar battery. Actually the OEM battery was closer to 7 years old as the truck was manufactured in Nov. 2005.
     
  5. Peymack91

    Peymack91 Member

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    Battery was in the truck when I bought it. What happened was this: the ground cable was broken at the post clamp and was not grounding the battery while I was driving it one night. The alternator was not charging it, of course, and I got home just as my headlights went out and car almost died as I pulled in the driveway. Didn't know about the crack, so I pulled the alternator and battery and had them both tested. Alternator tested great, battery tested good. Found the crack and replaced the ground cable. No problems until Friday when the gauge kept reading lower and lower. Didn't drive it at all on Sat., Sun. or Mon. Today, it reads around 12v with the truck running. Every time I start the truck it reads lower.
    Sounds like running that battery without it charging has put the final nail in its coffin.
    P.S. - It is a voltmeter.
     
  6. Doug D

    Doug D Virginia Gentleman

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    Yeah, if it was nearly discharged, that probably hurt more than helped. If it had been a marine battery, no problem, but regular lead-acid batteries used in vehicles don't take to being almost completely discharged very well. You make get away with it once or twice when the battery is young, but after that it probably will kill it. 12 volts with the engine running is not good. It's probably not even charging the battery (If at all). Time for a new battery.

    If you have a trickle charger you could try to charge it overnight (remove it from the truck), but the odds are it is probably toast.
     
  7. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    How old is the battery? What happens when you do a load test and open-circuit test?

    To test, top off the battery at a 2A or even 6A rate until it's fully charged. Then wait a few hours for the battery to stabilize. Measure open-circuit voltage (no load). Should be about 12.6V. Then turn on the headlights and measure voltage every 5 minutes. After 15 minutes, should still be above 12.0 volts. If not, battery is toast.
     
  8. Peymack91

    Peymack91 Member

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    I'll try this all and report back. I think the battery is toast, though.
     
  9. AllanC

    AllanC Well-Known Member

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    Your 1991 Dakota has a voltmeter gauge in the instrument panel. It is not an ammeter. The gauge has 2 numerical markings: 8 and 18. Under normal engine running with low or high electrical load, the gauge need should be at the midpoint of travel between the markings. That coincides with a 13 volt charging rate and that is where is should be.

    12: Battery voltage dropped below a certain threshold or was disconnected. Same as the description implies.

    36: An open or shorted condition detected in the air switching solenoid circuit. The air switching solenoid is mounted on the air pump. It provides air in 2 different paths for exhaust emission control. Air is directed either to the exhaust manifold ports or downstream to the catalytic converter. Make sure its electrical connector is attached to the air switching solenoid valve on the pump.

    37: An open or shorted condition detected in the torque converter lockup solenoid circuit on the automatic transmission. There is an internal electrically operated solenoid that is controlled by the PCM. At the appropriate vehicle speed and after the engine has reached proper operating temperature, the solenoid is energized. A valve opens and allows hydraulic pressure to engage the 4th gear overdrive on the transmission.

    There are 3 different electrical control circuits on the driver side of the transmission. So it is easy to get confused. There is a 2 wire connector on the tail shaft of the transmission. This is the speed / distance sensor and is in the immediate proximity of the speedometer cable drive. There is a 3 wire connector on the side of the transmission that is mounted horizontally. This is the neutral start safety switch. There is a 3 wire connector that plugs vertically into the transmission. This is the 4th gear, overdrive solenoid. Make sure the connector pins and receptacles are clean and tight.

    41: Alternator field control circuit not switching properly. Many times when this code appears and/or intermittent it means the brushes on the internal slip rings of the alternator have worn sufficiently such that there is insufficient spring tension to maintain proper contact. Insufficient spring tension causes an intermittent electrical connection at the slip rings and the PCM detects this and sets diagnostic code 41. Many times you can remove the alternator and have it bench tested and it will be deemed to be properly charging. But in the under hood environment with heat and vibration, the intermittent charging comes and goes. The original equipment alternator on this vehicle was a Nippondenso unit. It is very easy to remove the alternator, remove the cover on back side of the unit and replace the brushes and have proper alternator charging restored.
     
  10. Peymack91

    Peymack91 Member

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    Tested the battery. 225 CCA out of a possible 660 CCA. The alternator is shot. Charging at 11.5v at idle. Not original unit, so no way to change brushes. Replaced it (and the battery under warranty) and everything is copacetic.
    Even the check engine light is off. I know I still need to address those other codes, but for now, I'm calling it a day.
    I can't find the overdrive solenoid and the manual is no help. Is it on top of the transmission?
     
  11. AllanC

    AllanC Well-Known Member

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    The solenoids that control the 4th gear and lockup engagement of torque converter are located inside the transmission. They are attached to the hydraulic valve control body. You have to drop the pan, fluid and remove the filter to gain access.

    The wiring connector to the solenoid control is on the driver side of the transmission. It plugs vertically into a socket on the side of the transmission. The factory service manual shows the wiring harness on page 21-40, fig 13. Page 21-72, fig 86 shows the solenoid attachment to the valve body.
     
  12. ImperialCrown

    Level III Supporter

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    Using a wrong or insufficient service manual is frustrating. Treat yourself to a correct factory service manual or Powertrain Diagnostic Procedures manual for this level of work.
    Many of the tests use the DRBII or DRBIII scan tool, but if you understand what they are testing, a volt-ohm meter can be used to perform many of the tests.
    Is this a 42RH (A-500) transmission? It may not be the electronic-governor RE yet. The solenoids themselves rarely go bad, but they are a good test point for diagnosis.
    Do you feel the 'extra shift' as the torque converter locks up going down the road? It may feel like a 4-5 gear shift.
     
  13. Peymack91

    Peymack91 Member

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    Trans. shifts fine. A little soft, but I'm used to a really firm shift in all my other cars. Not sure why the code was thrown.
     
  14. Doug D

    Doug D Virginia Gentleman

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    Keep in mind with a weak battery (low voltage) you can get "false positives" and other weird electrical oddities. With as many computer modules as there is on today's vehicles, proper voltage is critical.
     
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  15. Meester Beeg

    Meester Beeg Active Member

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    What happened? You stated earlier the alternator output was fine. Is the battery of the type the acid level can be checked? Are the terminals clean and tight?
     
  16. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    Right, those are false fault codes due to the low voltage. If transmission shifts fine, just keep driving and the codes will clear themselves in a week or two, if they didn't already after replacing battery.
     
  17. Peymack91

    Peymack91 Member

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    Sorry, guys, I thought I had closed this thread out. Changed out the alternator put in fresh battery and all is good. Check Engine light is off and no issues at this point.

    Thanks for all the posts!!!
     

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