Flickering Dash Lights and Head Lights 2004 Jetta BEW PD

[Mawcus]

2004 Jetta BEW PD 5 Speed 170k miles. Dash and Head lights have been flickering. The flickering seems to be related to a small stumble Im having at idle. The flickering matches the pulsing of the tachometer. Had a code for Cam Position Sensor. Replaced the CPS and symptoms were still the same. Noticed on VCDS Lite that with old CPS measure block 4 group 4 (which I am assuming is Torsion Value) was reading 2.2cf at idle and jumping to 2.8cf at higher rpms. After installing new CPS I was getting a Torsion Value reading of 1.1cf at idle that would bounce between 0.6cf - 1.1cf at idle and jump to 1.7cf at higher rpms. That makes me think the old CPS was giving an incorrect reading. Since CPS didn't fix the problem started checking other things. Battery is good 12.38V when car is not running and its staying charged so alternator should be good. Changed the alternator pulley, serp belt and serp belt tensioner a year ago. Pulled the battery and checked the grounds under the battery tray and they look good. No corrosion and they were tight. Got a code for Antenna on VCDS Lite saying something like "antenna open circuit". Antenna is broken off from base so there could be corrosion in there I suppose. Could be DMF but not hearing any sounds to indicate that. Dont think in tank lift pump is bad but could a bad one cause flickering? I've also seen mentioned that a loose timing belt and or timing belt tensioner could be the culprit. Cant think of anything else I've checked so hoping someone has some ideas.

Thanks

 

[puntmeister]

I'd take a close look at the timing belt & timing belt tensioner.

 

[burpod]

before doing something crazy liking timing belt, why don't you check with a voltmeter while the car is running highly highly doubt it is tb-related....

 

[Mawcus]

Had timing belt and all related parts replaced last Dec about 10k miles ago. Also had new cam installed. All done by a guru. Gonna check to see if belt is loose. Next step is to check things with voltmeter when car is running.
Also experiencing random hard starts. Sometimes after sitting overnight it fires up as soon as i turn the key. Other times it takes 3 to 4 seconds. Same thing when warmed up, random hard starts.
Flickering seems to get better once engine is warmed up but it still flickers. The stumble at idle is worse when engine is cold and becomes very slight when warmed up. No real performance issues except when putting around the parking lot after a cold start. Kinda stumbles and bucks a slight bit. Oddly enough my last two tanks were all time bests. Usually 41-42mpgs. Last two tanks were 44+
All these symptoms just recently started showing up. The last month or so. So far im stumped

 

[truck240]

Your symptoms are very similar to what I had on my car. I also had the TB done by a so called expert. The expert installed to tensioner with the tang in the wrong place. He put the tang in the groove between head and block. My tensioner broke but it was not obvious till I had symptoms like you are experiencing. The belt may feel tight but with the car running it was deflecting badly.
If it is not the TB then perhaps check what the voltage fluctuation is at the headlights. I believe with DRL lights engine running there is 13.1V & 13.7 with headlight switch on. To all you TDI experts could bad diodes in the ALT cause the OP's problems? Just guessing but maybe the ECU getting AC ripple.

 

[Mavrick]

Typical failing alternator. Try un plugging the alternator and see if the flickering stops.

 

[BobnOH]

Sure sounds like basic electrical to me.
There are a couple main grounds in the cabin, might be good to check those. Check engine strap ground (top of tranny), alternator wire connections. Also check that your alternator clutched pulley operates correctly.
Flickering lights is an interrupted electric signal, nothing to do with CPS, timing settings or any other engine control. Could be any loose wire, relay, fuse or connector.

 

[LNXGUY]

The KISS principle. I for one have no idea how this could be TB related (That seems like the first thing people like to throw out there though)

I'm with Bob on this one.. Loose wire, connector, something stupid I'm sure.

 

[VeeDubTDI]

Bad voltage regulator?

 

[PDiesoiler]

2004 Jetta BEW PD 5 Speed 170k miles. Dash and Head lights have been flickering. The flickering seems to be related to a small stumble Im having at idle. The flickering matches the pulsing of the tachometer. Had a code for Cam Position Sensor. Replaced the CPS and symptoms were still the same. Noticed on VCDS Lite that with old CPS measure block 4 group 4 (which I am assuming is Torsion Value) was reading 2.2cf at idle and jumping to 2.8cf at higher rpms. After installing new CPS I was getting a Torsion Value reading of 1.1cf at idle that would bounce between 0.6cf - 1.1cf at idle and jump to 1.7cf at higher rpms. That makes me think the old CPS was giving an incorrect reading. Since CPS didn't fix the problem started checking other things. Battery is good 12.38V when car is not running and its staying charged so alternator should be good. Changed the alternator pulley, serp belt and serp belt tensioner a year ago. Pulled the battery and checked the grounds under the battery tray and they look good. No corrosion and they were tight. Got a code for Antenna on VCDS Lite saying something like "antenna open circuit". Antenna is broken off from base so there could be corrosion in there I suppose. Could be DMF but not hearing any sounds to indicate that. Dont think in tank lift pump is bad but could a bad one cause flickering? I've also seen mentioned that a loose timing belt and or timing belt tensioner could be the culprit. Cant think of anything else I've checked so hoping someone has some ideas.

Thanks

Your battery is only at 75% SoC. If V reads 14+V while running...it's time for a new battery

 

[Mawcus]

I agree with the flickering lights probably being an electrical problem. Gonna check out alternator, grounds and etc... As thoroughly as i can as soon as i have more time.
Ive also got a stumbling problem at idle that seems to match the flickering lights.
Post is here
http://forums.tdiclub.com/showthread.php?t=448977
I feel like stumbling and flickering are somehow related. Had a code for camshaft position sensor and thats why i replaced the cps.
Flickering and stumbling could be two seperate problems but they both manifested themselves at the same time.

 

[Dimitri16V]

Is the accessory belt tensioner bouncing around ?
Measure resistance from (-) pole to cylinder head , should not be more than 0.5 ohms

 

[Mawcus]

Is the accessory belt tensioner bouncing around ?
Measure resistance from (-) pole to cylinder head , should not be more than 0.5 ohms

Havent noticed serp belt bouncing. Wasnt specifically looking at it but didnt notice. Will check it out. Should be good tho. Replaced belt, tensioner and alternator pulley within the last year.

 

[DonCarroll]

more then likely the Alternator Clutch has gone bad , this happened on my Jeep liberty diesel, easy to see on my jeep , but much harder on VW tdi's

 

[Mawcus]

Checked the in tank fuel pump by pulling fuel line (the one that doesnt go to the t fitting on filter) an sticking it in a jar then cycling the key on and off without starting. Nothing really came out. Maybe a few drops. Also listened under back seat for pump to cycle but didn't really hear any thing noticeable.
Is it possible that the pulsing I have at idle when cold is the tandem pump, pumping fuel from the tank and priming the system and once it's primed the pulsing at idle smoothes out. stumble/pulsing usually smoothes out in a few minutes.
Pretty sure I will be installing a new in tank lift pump soon.

 

[LNXGUY]

A dead liftpump definitely isn't going to help the situation. Get one from Mike @ Defendertech. Way cheaper them OEM.

 

[Mawcus]

New camshaft position sensor, new intank lift pump and new battery and still having the same stumbling and same flickering of lights. Bought new Interstate Mega Tron 94r h-7 battery yesterday and was a little surprised when I checked the voltage right off the shelf and it was 12.47-12.49. Old battery was a little low after sitting over night but after its been charged by car it was reading same as new battery. Checked new battery today after car had been sitting at the park n ride for 9 hours. It read 12.44v. Seems like it should be higher than that with a brand new battery. Running I'm getting 13.52v, so as I understand things the alternator is good. Not sure what's next. Ive always had luck troubleshooting problems and good luck replacing the part/parts causing the problems but with the stumbling and the flickering I've thrown 3 parts at it...cam position sensor, intank lift pump and battery with no results. All were parts that weren't functioning 100 % (had a code for cps, old lift pump didnt work, 7 year old battery was on the way out) but also didn't fix current problems.
I'm sure flickering lights is some loose connection somewhere.
Stumbling for 1-3 minutes at idle when car has been sitting overnight...not sure what to think of that.
Also noticed that tach doesn't move when cranking the starter. About to look up what that may indicate.
Any help is appreciated

Thanks

 

[Alchemist]

Perhaps some other BEW owners could report their experience, but I don't ever recall seeing the tach read while cranking. Mine doesn't read until about 3 seconds after the engine is running.

 

[Mawcus]

Well the flickering lights and stumbling at idle on cold starts turned out to be a voltage drop between the battery and the alternator. Took to a mechanic to solve a flickering lights problem and they discovered a 2v drop between battery and alternator. I'm sure I failed at some basic electrical troubleshooting by not discovering this myself. I checked battery and alternator individually but I didnt check between the two. It is my understanding based on what mechanic told me that you check between the two by checking positive on battery and positive on alternator with multimeter. Anyway I had given up on troubleshooting it myself so I took it in. They replaced the cable/harness that goes from alternator and battery and now the car seems fine. Flickering lights and all previous symptoms are gone.

 

[Mawcus]

Well problem with flickering lights is back. But now its only happening when starting the car cold. Flickering goes away once car is warmed up.
Here's a link describing other symptoms I'm having with cold starts
http://forums.tdiclub.com/showthread.php?t=465626

 

[Dimitri16V]

If lights flicker there is a problem with electricity ... Even if charging is subpar , there should be enough juice off the battery. UNLESS , the path to the various electricity consuming items is resistive
Battery poles clean and clamps tight ?
Resistance to ground ?
Resistance to alternator ?
Battery fuse box corroded ?

 

[Mavrick]

Clean connections, replace alternator or voltage regulator.

 

[Mawcus]

i'll check those out too. Im thinking it could be the glow plugs. havent had the recall done so its the factory glow plugs that are in it now. could the flickering and stumbling be caused by faulty glow plugs cycling on and off? Wondering if i could just disconnect the glow plug harness to see if the glow plugs are causing the problems or is that a bad idea. This morining it was about 55 degrees. started it up and it stumbled, ran rough and the lights were flickering for about 2-3 minutes about a mile or so. then it smoothed out. ran smooth and lights stopped flickering. no problems once its warmed up

 

[BobnOH]

You can disconnect the glow plugs, but that ain't it. Loose connection, bad wire or grounds most likely.

 

[Mawcus]

i agree but also the flickering and stumbling goes away after a couple of minutes. so whatever it is its only happening when the car has sat overnight or isnt warmed up and it only happens for a few minutes. if it is a loose connection, bad wire or grounds then its only getting juice under those cold start conditions

 

[wonneber]

Light flicker

Well problem with flickering lights is back. But now its only happening when starting the car cold. Flickering goes away once car is warmed up.
Here's a link describing other symptoms I'm having with cold starts
http://forums.tdiclub.com/showthread.php?t=465626

I'm not a fan of resistance tests all the time.
With lights I prefer to do a voltage drop test.
Measure from the battery + to the light + terminal. More then a few tenths of a volt is not good.
Same for the negative side.
If the lights flicker that bad you should see higher voltage readings.
Trace the drop backwards to the source.
There is a ground connection under the battery tray known to be bad.

Every now & then I see my running lights flicker when I release the parking brake. Only lasts a few seconds.

Rich W.

 

[BobnOH]

I'd continue with the connections service. clean the ground on top of the transmission case, and at least the 2 grounds in the front of the cabin, inside.

 

[Dimitri16V]

i agree but also the flickering and stumbling goes away after a couple of minutes. so whatever it is its only happening when the car has sat overnight or isnt warmed up and it only happens for a few minutes. if it is a loose connection, bad wire or grounds then its only getting juice under those cold start conditions

Worn brushes or shot alternator or poor grounds

 

[joep1234]

Have a load test done on the battery and alternator and check all of your grounds. The main one that gives so much trouble is the one under the battery box. It has problems from the battery and water getting to it.

 

[Mawcus]

Well the battery is completely dead (less than a year old). Car wont start with dead battery. It will start with a jump. The rough starts continued along with the stumbling and lights flickering as described earlier but just a few days ago i started it cold, drove about 2 miles, parked it, immediately tried to start it again and it just cranked and faded until it was dead. Today when the car is running after I jump it, Im getting 13.45v to 14.06v when i did about a minute long log on VCDS Lite. Pretty much the same with Multimeter on battery. About an hour later I did another quick VCDS log without car running and voltage had dropped to 10.41v
I realize if the battery is shot (even though its relatively new) it wont hold a charge. Its seems the alternator is working based on VCDS log and multimeter reading when car was running. Voltage did jump when car was started/jumped making me think the alternator is good.
I also got several codes with VCDS
VCDS-Lite Version: Release 1.2
Control Module Part Number: 1C0 909 605 F
Component and/or Version: 04 AIRBAG VW61 0202 0003
Software Coding: 12340
Work Shop Code: WSC 00066
VCID: 2721789FD6F5
1 Fault Found
00532 - Supply Voltage B+
07-10 - Signal too Low - Intermittent
------------------------------------------------------------
1 Fault Found:
01316 - ABS Control Module
49-10 - No Communications - Intermittent
--------------------------------------------------------------
1 Fault Found:
00778 - Steering Angle Sensor (G85)
49-10 - No Communications - Intermittent
--------------------------------------------------------------
00668 - Supply Voltage Terminal 30
07-10 - Signal too Low - Intermittent
--------------------------------------------------------------
00856 - Radio Antenna
36-00 - Open Circuit
One of the main things i suspect is that there is some sort of Parasitic Draining of the Battery going on. Recently my turn signals started acting up. Replaced the relay in the dash and problem solved. Shortly after that i heard the speakers crackling and popping when the car was off, radio was off and the key was out of the ignition. So possibly radio is killing battery.
Another idea is that the alternator is dead and or the voltage regulator. I did notice the multimeter briefly jumping around erratically with low readings right after i pulled the jumper cables and the car was stumbling like is has been (also might not have had good contact with terminals)...so maybe voltage regulator was acting up on cold starts but smoothed out after it warmed up
Sorry for long winded, possibly disjointed post but this has been driving me nuts. I dont have the best understanding of electrical issues. I'm mechanically inclined but not electrically. Ive checked most of the obvious grounds and connections and Ive done some basic tests with a multimeter and VCDS Lite trying to isolate the problem (Battery, Alternator, Voltage Regulator or Parasitic drain) and ive scoured this site and the rest of the interweb. Trying to figure this out before i have to take it to the shop. Luckily i have some time because the shop is backed up 2 weeks.
So far I haven't figured out much so any help is much appreciated
Thanks