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Intermittent flashing coil lamp

13K views 15 replies 9 participants last post by  Mosquitoe 
#1 · (Edited)
Since the snow came the other week, the glow plug lamp flashes but not
all the time, now the check engine lamp is on, no reduction in power and no codes stored in the ecu? Anyone had this combination of odd things?
It's an 08 2.5 130, dpf removed and pendled...
 
#3 ·
Yes, had same situation, occasional glow plug light, then later engine light........took it to a local independent VW specialist..."hum strange no fault codes".......after fiddling about with some of the cable connections the engine light disappeared (after removing fault reader & restarting engine)????

The glow plug light has returned (motorway driving only) a couple of time since, still trying to figure it out!
 
#5 ·
Could be 1) your brake light bulb has blown, 2) but I would guess its you brake light pedal switch, easy cheap fix however there are a couple of types, it simples unscrews half a turn from the top of the brake pedal once off you can se how many connections it has then replace it, its like a kind of rachet plunger thing. Good Luck
 
#8 ·
I've checked the brake light switch, works brake lights as it should. Removed brake light switch and checked for signs of wear inside it, all good.

Now when the coil light flashes, power is reduced, it wont allow boost. Yet when the coil lamp stops flashing, power restored.
Engine check lamp is sometimes on, sometimes not but has no bearing on the power.

Brake bulbs (non-led) checked and found to be working and tight in their housing.

Towbar wiring checked and found to be ok, no chafing and good insulated connections.

VAG Com cable sourced from forum member, just got to wait until her returns from hols before I can try looking into codes with a more specialist code reader than the one I already have.

Bloomin frustrating, sometimes there power and all is well, sometimes it feels like I'm towing a sherman.

It's now relegated to the drive... I wonder if mazda bongos/transits have these problems?:*
 
#9 ·
VCDS diagnostics is definately the only easy way to repair these modern vehicles. They are so complicated, that to try and do it by old methods of multi meter and osciloscope etc would take forever.
Without this sort of kit, you can spend huge amount of time and money guessing, and repacing perfectly good components.
I'm sure when you get the VCDS on loan, all will reveal itself. Good luck!
 
#10 ·
Got version 704 vagcom working on nieces laptop and pulled the following:
Address 01: Engine Labels: None
Part No SW: 070 906 016 EC HW: 070 906 016 DS
Component: R5 2,5L EDC 000SG 2539
Coding: 0000072
Shop #: WSC 66565

1 Fault Found:
001031 - EGR Potentiometer (G212): Signal too Low
P0407 - 000 - - - MIL ON
Freeze Frame:
Fault Status: 11100000
Fault Priority: 1
Fault Frequency: 1
Mileage: 211401 km
Time Indication: 0

Freeze Frame:
RPM: 777 /min
Speed: 0.0 km/h
Load: 0.0 %
Lambda: -25.0 %
Mass Air / Rev.: 1100.0 mg/str
Mass Air / Rev.: 515.0 mg/str
Bin. Bits: 00000000

Readiness: 0 0 0 0 1

EGR needs looking at then...
 
#11 ·
16791/P0407/001031
Contents [hide]
1 16791/P0407/001031 - EGR Potentiometer (G212): Signal too Low
1.1 Possible Symptoms
1.2 Possible Causes
1.3 Possible Solutions
16791/P0407/001031 - EGR Potentiometer (G212): Signal too Low

Possible Symptoms
Malfunction Indicator Light (MIL) active
Possible Causes
Wiring/Connectors from/to Exhaust Gas Recirculation (EGR) Potentiometer (G212) faulty
Exhaust Gas Recirculation (EGR) Potentiometer (G212) faulty
Possible Solutions
Check Wiring/Connectors from/to Exhaust Gas Recirculation (EGR) Potentiometer (G212)
Check Exhaust Gas Recirculation (EGR) Potentiometer (G212)
 
#13 ·
Right, egr removed and cleaned (wasn't too dirty), and all moving parts moved, nothing stuck. Broken wire on plug to n18 egr valve fixed. Ran vagcom again, code 001027 now present and won't be cleared. Engine power restricted but seems smooth with steady idle, no excessive smoke etc...

Even changed the black plastic egr cover with mni geeks but alas, same problem... I tried the vagcom output test of the egr which does on-off-on-off etc but it doesn't make a sound like its opening/closing so I'm guessing the actual valve is faulty even the plunger to opens the valve can be moved by hand which only points to the motor that controls the plunger...

Reluctant to shell out on a new egr without some reassurance that's to blame... Any one else had this code?
 
#14 ·
So, as all connections, hoses, etc had been checked numerous times and the vagcom was pointing to the egr, which didn't seem to be opening and closing with the output test, I bit the bullet and replaced the egr valve for a new one.
Reassembled all parts, checked connections, turned key to position 1, glow plug light on, then off as per normal so I start the van.
After 30 seconds, glow plug light starts flashing again.

Sense of humour failure, much swearing and I've decided to come inside before I make expensive mistakes with a wide variety of tools...

:confused::(:*
No longer feeling the love for the van, the egr, the f$*kwit that designed it and put the bolts in hard to reach locations etc and deciding that getting a van to inhale its own sh01te was a good idea....

I hereby admit defeat and will accept the first reasonable offer... Yep I'm that annoyed with it.
 
#16 ·
For what its worth, after an MOT fail for a failed nearside brake light, I noticed my glow plug warning light flashing; I read this thread and checked the brake lights; sure enough, the nearside light had gone -I replaced it but no change - warning light still on. Checked brake lights again, and found the offside brake light not working. Changed that and so far, no more warning light.
 
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