voltage read 19 volts
 

2001 Jeep cherokee running down road get check gauges lite - voltmeter
reading 19 volts - shut key off and back on gauge reads normal 14 volts - this
only happens every once and while, is there a problem with electrical system or is and alternator problem fixing to happen - has anyone had this happen

My 2000 has been doing this intermittently for the 4 years we've owned it. Tested alternator and have hooked it up to my buddy's Modis system a couple of times and never nailed anything down. The most mine has ever done it was 4-5 times across the span of 2 days, and oddly enough it was in your neck of the woods (Willis). I figured it to either be rain/humidity or it was just the little Jeep's AMC heritagge showing through!

The alternator and the voltage regulator (inside the computer) are possibilities.

But before you condemn either of those, for an "intermittent" problem like you are experiencing, I would start with refreshing the engine grounds. And along with that, be sure to refresh each and every connection related to battery (battery cables) and alternator. Simple things first. Always.
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Grounds can be the root cause of many electrical gremlins. Refreshing grounds is NEVER a bad idea, and the investment of your time in this procedure is always well worth it!

You can't tell much of anything by looking at ground connections!! You must remove, scrape, clean until shiny the cable/wire ends and whatever they bolt to. Be sure to remove all paint from any ground connections.

Start with the one on the back corner of the head, and where it attaches to the firewall, as it deteriorates over time and is an area that makes it susceptible to damage. Best to replace that woven cable with a #4 or #2 gauge cable. You can attach the one end to the intake manifold if you would like.

Next go over to the engine dipstick tube stud. Remove the nut and clean the wire ends and scrape the block until shiny at the stud. Reattach tightly.

If you are so inclined, add at least a #6 cable from the negative terminal of your battery to one of the bolts on your radiator support.

McRay has a 2001 XJ.

Remove your battery and verify the battery temp sensor is not broken,


Unplug the battery temp sensor connector and check for corrosion in the pins and pin cavities.

One thing to check might be the battery temp sensor...mine was doing this a long while back, and when I took everything apart to track it down, the harness/pigtail at the sensor was pretty chewy. Replaced it and haven't had an issue since. The temp sensor is directly related to charging.

You beat me to it, Ken...was typing my response while you were posting already, LOL

It's always good to have someone describe how a similar problem was solved.

Resurrecting an old thread for the same issue. 2001 XJ, 4.0 with a 160 amp Durango Alternator that idles at 13.8VDC (confirmed with volt meter). 3 month old Optima Yellow top battery. Battery, alternator and ground (both from battery to frame and frame to engine block) cables are 2/0 gauge audio grade cables. No cranking issues. I've been running this setup for almost a year without any issues before now.

Yesterday I was driving home and the voltage gauge in the cluster pegged at 19VDC. I was on the freeway so it took me time to get off and get to where I could stop. By the time I did, the gauge had returned to normal. Started driving home and it happened again (19VDC while cruising, back to normal on stopping).

This morning I hooked a digital volt meter to the battery (my battery is under my rear seat) and drove to work. As expected, got on the interstate and the voltage gauge pegged at 19VDC. Volt meter confirmed rock solid 14.2VDC the entire time. When I stopped, the volt meter showed 13.8VDC and the voltage gauge returned to normal. This indicates to me that the alternator, voltage connections, and battery are good. So I'm at a loss.

Any input?

Points to something flukey with the gauge. What, idk.

**Now I do know. After pulling the instrument cluster and dissecting it, I discovered I was barking up the wrong tree. Nothing was wrong with the gauges.
THE ANSWER IS: and this goes for all the Chrysler 'went to 19V" issues...this pcm regulator / batt temp sensor issue has come up on multiple forums and threads for a host of said vehicles.
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The battery temp sensor is not jiving with the voltage the voltage regulator is expecting. When your engine compartment heats up, the sensor does too, and accordingly the PCM dials back the charging voltage. It also dials back the charging voltage it expects to see, accordingly. IF the sensor is reporting a shad too few K-ohms, say 2k ohms for instance, the pcm reads a higher ambient temp and dials back the charging voltage. If then the charging voltage exceeds this parameter, the PCM will peg the volt meter and ring the chime and the Check Gauges light comes on. Not that you are charging at 19 VDC, but to alert one that one's charging system is charging too high for the temperature.

With my external reg, I added the 2k and fixed it instantly. Had no effect on the actual charging voltage, as that is completely regulated by the external regulator. The old field wires to the alternator just go to dummy load resistors so as not to set the "Disconnected Alternator Field Wires" code.
Got that? Lo;

What are "voltage connections"?

I would repeat your test with the multimeter hooked to the alternator. If the alternator is outputting 19.0 volts then you have to start looking for bad connections, particularly around the PCM.

If it's 14.2 volts start looking for bad connections (I'm really just curious to see what alternator does during the "pegged gauge" issue).

Since you're ending up with proper voltage I'm really not thinking it's the PCM. That said, I'm wondering if it could be a broken solder joint in a non-critical area on the board.

If your battery is in the back seat, what did you do to the battery temperature sensor to avoid issues (up until now anyway)?

This is a frequently reported issue on the boards that must get fixed somehow but rarely do the posters put the solutions up. It would be nice to know if it's like always the same wire, etc.

Re: solder connections this from a minivan I had where everything in the instrument cluster randomly went out. Note solder connection just to right of center last one in the row:

https://scontent-mad1-1.xx.fbcdn.net...cb&oe=5D05AA20

It was late, I meant to say electrical connections (not voltage connections). I'm saying that the main wires and grounds (alternator, battery and grounds) are solidly connected and clean.

My battery is connected to my alternator via a 2/0 gauge wire (through a 250 amp fuse). IF I had 19 volts at the alternator, I would have 19 volts (or at least 18.9 volts) at the battery and everything in the vehicle would have been fried.

I originally just cut the sensor off, shrink wrapped the ends to prevent shorting and it worked like this for 6 months. This issue only started a few days ago and when I reinstalled the temp sensor, the issue did not resolve (and tells me it's not the battery temp sensor).

Are you saying it might be a solder joint on the gauge cluster?

No, I would look for all the connections on the PCM itself. See


I'm really not thinking it's the instrument cluster itself cause those issues usually result in dead gauges.

That said, I have never seen a consistent solution to the 19 volt XJ problem, so if you find it you'll get the Silver Star.

I also had a situation where the master door lock in the XJ would only work when it was cold (HAH?) Turned out there were several broken soldered connections in the passenger side circuit board.

Sometimes things are just weird....