98 XJ P1968 Code and other Issues - JeepForum.com
 
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post #1 of 10 Old 12-21-2015, 05:56 PM Thread Starter
antcg
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Xj 98 XJ P1968 Code and other Issues

So first a little back story.

I was driving down the interstate today and had my CE come on. So I stop to get gas and just do an overall check of my Jeep. It starts and runs fine so I take to an Advance Auto down the street and get the code pulled. I have never seen or heard of this code, but from what I understand the ECM/PCM is not communicating properly?

So I decided to continue down the interstate and then all of a sudden my Check Gauges comes on and my alternator isn't charging. So I did not have my multi meter at the time and was not near any parts stores so I turned off all accessories and went on. Once I got there I realized one of my headlights was out. I had to make it back home, and it would still crank. So I drove 45 mins back home and test the battery which is reading 12.2 volts off and about the same when running at idle, but the gauge still reads at 9.

What could cause a CE for the P1698 and then my alt to not charge? Could they be related or just a coincidence? I plan on checking my grounds tomorrow for the ECM when it is daylight. Would anyone else have any other suggestions? Or need any more info.

Thanks

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post #2 of 10 Old 12-21-2015, 06:44 PM
CJ7-Tim
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Maybe it is the other way around, low voltage caused the P1698. 9 volts on the dashboard gauge indicates low voltage, usually due to a faulty alternator.

P1698 Jeep - ECM Fault No CCD Message From TCM

Possible causes

- Low battery voltage
- Engine control Module (ECM) harness is open or shorted
- Engine control Module (ECM) circuit, poor electrical connection
- Faulty Engine control Module (ECM)

.

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post #3 of 10 Old 12-21-2015, 06:54 PM Thread Starter
antcg
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Quote:
Originally Posted by CJ7-Tim View Post
Maybe it is the other way around, low voltage caused the P1698. 9 volts on the dashboard gauge indicates low voltage, usually due to a faulty alternator.

P1698 Jeep - ECM Fault No CCD Message From TCM

Possible causes

- Low battery voltage
- Engine control Module(ECM) harness is open or shorted
- Engine control Module (ECM) circuit, poor electrical connection
- Faulty Engine control Module (ECM)
Did not think of that. But would that be the case even though it threw the code before the alternator was reading low voltage?
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post #4 of 10 Old 12-22-2015, 10:06 AM Thread Starter
antcg
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I took out the alternator and went and got it tested and it passed the three times they ran it. So that leaves fuses or wiring and worst case the ECM itself I guess?
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post #5 of 10 Old 12-22-2015, 05:10 PM
CJ7-Tim
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If the alternator was reading 9 volts, it is most likely the brushes are worn and sticking. Hitting a bump or removing the alternator for testing will often un-stick the brushes, resulting in a false positive test result. If the 9 volts happens again, suspect the brushes. Clean and tight wire connections and non-corroded wires and wire connectors are always good to have.

.

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post #6 of 10 Old 12-22-2015, 10:52 PM
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engine running. you do not have greater then 12.9 volts your alternator is not charging. i would double check at the B+ terminal on the back of the alternator while running to eliminate the possibility of a bad connection at the battery. a low charge will most likely cause that code. ideally you want 14.5 volts idling. but it always vary s. anything above 13 is usually normal.
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post #7 of 10 Old 01-01-2016, 03:01 PM Thread Starter
antcg
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And its back...

Well after putting it all back in and replacing the battery ground and the battery to body ground it fixed the problem. Today the CEL came back on, same code. This time the alternator is still charging but only at about 13.5 volts. Seems to run and drive fine. Not sure what to check next? Will see if the alternator stops charging again.
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post #8 of 10 Old 01-01-2016, 04:58 PM Thread Starter
antcg
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Quote:
Originally Posted by CJ7-Tim View Post
If the alternator was reading 9 volts, it is most likely the brushes are worn and sticking. Hitting a bump or removing the alternator for testing will often un-stick the brushes, resulting in a false positive test result. If the 9 volts happens again, suspect the brushes. Clean and tight wire connections and non-corroded wires and wire connectors are always good to have.
And now same issue all over again. I don't see any kind of corrosion on the wires, some of the ends are a little dirty. Not sure if i should try and tackle wiring, the alternator or replace the ECU?
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post #9 of 10 Old 01-01-2016, 10:32 PM
Jeepkruzer
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Quote:
Originally Posted by antcg View Post
Not sure if i should try and tackle wiring, the alternator or replace the ECU?
If it was mine (and granted, it is NOT), I'd buy a rebuilt Denso alternator from RockAuto and replace the current one that you have on there, especially if you don't know the past history of your alternator. I'd bet money that this will fix your problem.
Then take the (assumed) faulty alternator that you have now and have it rebuilt by yourself or a competent starter/alternator shop.
Second choice would be to buy a complete brand new one from RockAuto. It will also probably fix your problem, but chances are it will be made in China and the fix may not last a full year.
BTW, I have yet to see a discount chain employee properly test an alternator that replies on the ECU for the voltage regulator.

With that all said, competent troubleshooting should be performed before parts are thrown at it.
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post #10 of 10 Old 01-02-2016, 08:18 AM Thread Starter
antcg
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Quote:
Originally Posted by Jeepkruzer View Post
If it was mine (and granted, it is NOT), I'd buy a rebuilt Denso alternator from RockAuto and replace the current one that you have on there, especially if you don't know the past history of your alternator. I'd bet money that this will fix your problem.
Then take the (assumed) faulty alternator that you have now and have it rebuilt by yourself or a competent starter/alternator shop.
Second choice would be to buy a complete brand new one from RockAuto. It will also probably fix your problem, but chances are it will be made in China and the fix may not last a full year.
BTW, I have yet to see a discount chain employee properly test an alternator that replies on the ECU for the voltage regulator.

With that all said, competent troubleshooting should be performed before parts are thrown at it.
The alternator that is in there was replacement from over a year ago, and was a rebuilt I'm sure. I've been thinking about just throwing parts at it. Going to go through grounds today and possibly get a new alt. If I do that I'd like to go ahead and throw the 130 amp option in, does it just bolt in? Are there any physical size differences?
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