Got the ODB2 scan tool and started messing around with that this morning. Recorded a test run on some parameters. With the Envoy in park, no AC, the voltage indicator on the Scan XL program shows the voltage at about 13.6 volts and fairly steady. The RPMs show the desired idled speed at 626 which sounds consistent with many posts here, but the report shows the idle speed range going from 579 to 632 with 616 being the average. Turn the AC and lights on, the report shows the voltage runs from 13.5 to 13.9. The I couldn't find any PIDs to set up for "alternator" - all I can find is "generator" so I added those to the data capture. It doesn't give a voltage reading but a percentage which I didn't quite understand. I was looking over all the data it was capturing and it's showing some cylinder misfires so is that normal? Any specific PIDs I should set up for my electrical issues on this program?
Flickering dash lights and courtesy lights on '04 Envoy
- Thread starter jimmackey11
- Start date
floridarv
Member
- Mar 30, 2013
- 59
Jim, check out this thread http://gmtnation.com/f23/liftgate-problems-dealer-says-3526/ Read #26 in the thread. He talks about this caused his dash lights to flicker.
Just a thought.
Just a thought.
Great suggestion - I've had to repair those a while back (as I think just about everyone with an Envoy!) I've rechecked that whole wire strand again and everything looks good.
I'm not sure if this is related or not, but playing around with the ScanXLPro this weekend (man, I've got a lot to learn there) and I show a code C0055. I'm not getting any SES light and thought maybe it was old and cleared it out but it's back this morning.
Yes I did - that might be the cleanest, tightest ground on the whole Envoy! It looked brand new. Thanks for the idea - keep 'em coming until I can figure this out!
jimmackey11 said:
Going off of the OEM service info:
So I think the more that you loaded the alt down, the percentage would go up.
The other scan tool definitions were On/No output for Gen L and the ignition 1 voltage.
I don't know of any other PIDs that can help rule out anything else.
Oh, and about the misfires, I see that often while reading live data for unrelated things.
It's been a busy few weeks and I've been unable to get to any work on the Envoy, but I have noticed over the last week or so that when I open the liftgate that the latching sound it used to make within a couple of seconds on opening and closing the LG has become slower and slower. It's to the point it takes about 10 minutes or so after I open the LG before it makes that latching sound now. The LG works fine as do the remote locks. I've gone over every inch of the wires and connections several times from the end of the roof liner to the LCM and they all look great. I'm curious if this all could be related?
To me, that would seem real obvious that either the alternator and/or battery are bad or dying, but they are both relatively new - a couple of months old on each. And I've had both of them repeatedly tested at several different places and they always test out perfect which makes this even more frustrating. Several people have commented that they've had alternators that tested out fine but, in fact, were bad or had a bad diode. I'm just trying to avoid the "shotgun" approach and just start replacing parts that might be good!
jimmackey11 said:
I hear ya and believe me the last thing I want to see is anyone to throw a part at something on a whim. It's unfortunate that many repair places rely on quick and easy test equipment (like the handheld "load" testers) as opposed to the more technical (see also: expensive) equipment. If I had an extra alt here I'd send it to you to try out to rule it out as the cause of the flicker.
Let the saga continue, it does make for interesting "forum news"...jimmackey11 said:
So you have made some "new" observations about your tailgate. Of course, those observations are made with your truck off, right? Are they the same with your truck running, my good Dr. Watson...
Brilliant question, my dear Budwich! With the Envoy running, when I open and shut it the latching sound happens almost immediately! Turn it off, and the delayed response returns.
Went out and bought a brand new battery today and........still have the delayed LG mechanism after opening and closing. Basically, no change whatsoever
???? OK... surely though after what we have been thru with your "astute observations", you would be providing us with a little more than... got a new battery, no change... further, the "dying battery" comment was in response to the "latest observations" about the slowness of the tail gate, not necessarily the "root cause". So again, is there a difference with the "new battery" and the tail gate, with the vehicle running versus off? Next, a new battery doesn't necessarily mean a full charged battery although some places will "quick charge" if asked. Further tests, on this battery, with vehicle (not running) but with headlights on along with fan and wipers, what does the voltage at the battery read.
Budwich - excellent questions (as always)! I did have them charge the battery first and, I didn't check it out thoroughly myself which I should know better so shame on me. The battery wasn't 100% up to charge so I took care of that myself and the problem stopped! However, today for some reason, the LG latch on opening the LG did not make that noise which was the first time in a week that has happened. Unfortunately its late and dark and too many mosquitoes to mess with now but will attempt some more battery testing tomorrow or Tuesday. I'm starting to think the alternator is quirky and isn't fully charging but it must be randomly happening?
As I "insinuated", the battery is necessarily the "root cause" of your problem. As you have found, it is likely the reason for the difference in LG response between "engine running" and "vehicle off". However, your "root cause" of why your battery was "dying" could be a bad battery (ie. dead cell or otherwise) or it could be your alternator not doing its job for its own "reasons". That's kind of where you are at. Since you have replaced the battery a couple of times now, it would appear unlikely that you have gotten bad batteries so your "search" for the root cause (of all your problems maybe) continues assuming the LG operation "differences" are related to the original post.... quite a saga. It looking like the alternator is a good candidate but that might not be the case directly... but maybe .... there are a couple of charging system (ie. alternator setups), one where the output voltage is controlled to help split the load between the alternator and battery and the more traditional "continuous charge" mode. The "controlled mode" (sorry can't remember what the official name is ... PMS power management system?) might have a control issue as opposed an actual issue with the alternator. My guess is still that you have lost a diode and so you aren't actually getting a very good DC wave form which is likely not helping your battery very much. Probably the only way to check that would be a scope to look at the output wave form.
kkoether
Member
- Aug 18, 2013
- 37
budwich said:
If you suspect AC ripple on DC voltage you can switch you meter to AC to check for it. I do this all the time looking for bad power supplies on machine tools. That said I don't know how clean the DC voltage will be out of a properly operating alternator. I have never tried this trick on a running car. I would suspect it to be pretty close to 0 VAC though. Good Luck.
I changed for a new battery over a month ago and everything seemed ok. No more flickering dash light or courtesy lights, and whatever the LG mechanism sound that it makes right after you open or close the LG was happening as normal. About 2 1/2 weeks ago, that LG noise stopped completely. It won't do it with the car running or turned off. I'm not exactly sure what that mechanism does but I don't seem to have any problems with the LG working or locking. Should I be concerned or not? What exactly does that noise mean when you open and close the LG? Now today that LG sound happened when I opened it first thing with the car off and then when I shut it, but nothing since either running or not. The flickering light problem has not returned.
Mark20
Member
- Dec 6, 2011
- 1,630
The other week when I was running to get some RV anti-freeze for the camper the headlights and interior lights were noticeably dimming. I also caught the dash gauge dropping below 14V. On the way home I was waiting for more of the same and nothing, perfect operation. I'm wondering if the alternator is going, that happened on my old Tran Sport van but they were definitely flickering constantly, a sure sign of the regulator going. This is random.
Off to check the grounds and alternator connections plus search here some more.
BTW, the battery is only a couple of months old.
EDIT:
Just found Roadie's note about the SAIS (air pump) diagnostic test. It was getting cool/cold that evening.
Off to check the grounds and alternator connections plus search here some more.
BTW, the battery is only a couple of months old.
EDIT:
Just found Roadie's note about the SAIS (air pump) diagnostic test. It was getting cool/cold that evening.
The SAIS test doesn't depend on the temperature outside. It runs every drive cycle after a cold start when certain conditions are met, which usually happens within a few minutes after start-up a few miles down the road. The conditions include driving at a steady RPM, so it's going to happen at a time when you are least distracted by merging onto a highway, or stop and go city traffic. And just after daylight savings time goes away, the evening commute in the dark is now the most likely time for you to notice the voltage drooping after you notice the light flicker and then glance at the gauge for confirmation. In the summer, and on most people's morning commute, the diagnostic happens in daylight, and you just never get that visual clue to glance at the gauge exactly when the diagnostic is happening.Mark20 said:
I ran a wire from the circuit that powers the exhaust manifold solenoid to a LED that I put at the edge of the hood so I could confirm all this years ago. You see, I'm nuts about mystery system operation.
At the air injection solenoid on the exhaust manifold, black wire is ground, and the pink/black wire goes to 12V when the system is active. That comes from the front fuse block relay #55. So you can put any sort of 12V test light from the pink/black wire to ground, or wind a tiny wire around the proper blade of the relay and plug the relay back into the fuse block. I use that trick all the time to monitor a signal that's otherwise tough to get to inside a harness. Discovering WHICH is the proper blade of the relay is left as an exercise for the student. There's only four. 
Flickering/dimming started this morning. 5 hour holiday trip tomorrow in the upstate NY, heart of the impending nor'easter.
Crossing fingers it's just a battery (05 still on factory battery...oops)
Not really keen on rolling the Grand Caravan over the river and through the woods to grandmother's house.
Crossing fingers it's just a battery (05 still on factory battery...oops)
Not really keen on rolling the Grand Caravan over the river and through the woods to grandmother's house.
the roadie said:
I agree, worth every penny and it's overdue.
Just took a 50 minute round trip to my kids' day care to give meds and this is what I observed:
Using a voltmeter on my radar detector (I know, not reliable, but the best I had in the moment) I showed 14.5 volts (fluctuates down to 14.3) until truck was up to operating temp, and then dropping to 13.7-13.9. On the return trip the reading held between 13.2 and 13.4, but dipped as low as 12.9 during light city driving. Volt meter on the dash showed similar. No flickering, I turned on all the interior lights, kept headlights on, radio on, and heat running, just like I did on the drive into work this morning.
That's normal behavior, and is an indicator that the alternator is fine. What will be a good test of the battery is to turn the engine off, add a load light the headlights for ten minutes, and watch the voltage droop. Compare that rate of droopage to a known good battery like on another vehicle, or do the math and see how much of a good battery's capacity is consumed in that sort of test.pejeeper said:
If kids and family and winter safety is involved, I wouldn't even be worrying about diagnosing anything to do with flickering or voltage droop if the battery is more than five years old. It's a ticking time bomb waiting for the worst possible combination of conditions to put the family in danger. Are you always carrying water, food, and heavy clothes as emergency supplies?
tbyoda
Member
- Apr 19, 2013
- 187
pejeeper said:
Based on what you are saying and were you are location is I'd say you are traveling to Rochester or Buffalo NY. Dude go buy a new battery! They is a winter storm warning in effect up here. First big snow up here going to be a mess. Calling for 5 -12 snow winds 20 -30 mph. Pack some boots, warm cloths, hats gloves, etc, food, water. Take main roads.
the roadie said:
Rs8892 said:Based on what you are saying and were you are location is I'd say you are traveling to Rochester or Buffalo NY. Dude go buy a new battery! They is a winter storm warning in effect up here. First big snow up here going to be a mess. Calling for 5 -12 snow winds 20 -30 mph. Pack some boots, warm cloths, hats gloves, etc, food, water. Take main roads.
Close. Watertown, NY I take 87 to 90 to 81. I grew up in the Rochester/Syracuse area and know the weather quite well. Grabbed a new battery, Optima Redtop, but alas, the flickering has not repeated. And the new Redtop is still sitting on my laundry room counter. Took the minivan up north and missed all the weather. Installing battery tomorrow and *hopefully* forgetting about the flickering.