ALH RPM drop + glow plug light

mk4gasm · Sep 15, 2014

I have a 2001 5spd Golf with 212000 miles.

I was doing 70mph the other day and the RPM's dropped 2-300 and gave me a quick jolt forward (like tapping the brakes) and the glow plug flashed once and went off. I changed the fuel filter, oil filters, and air filter and it still does it. I do have vagcom but it doesn't want to do it on the way home.

No limp mode. No stored codes when I checked.

Any ideas? I can't seem to find the right search phrase to find any similar posts to this.

EDIT: Adding a better description of what happens:

When the rpm's drop my CEL (racepipe) turns off and the glowplug light turns on for about a second, then after 10-15 seconds the CEL for the racepipe comes back on. It is almost as if my engine is stalling at speed and restarting itself.

Bob_Fout · Sep 15, 2014

Inspect / clean the needle lift sensor wires and plug that are attached to #3 injector. Should have set a code of if it was that, though.

whitedog · Sep 15, 2014

How about the throttle sensor?

RacerTodd · Sep 15, 2014

The flashing glow plug is sort of a super "check engine light". It flashes when the ECU detects that certain very important components are out of spec.

Per a post by MoGolf, the codes that cause a flashing glow plug light are below.

00741 Brake pedal monitoring - implausible signal
01044 Control unit incorrectly coded
16705/P0321 Engine speed sensor - implausible signal
16706/P0322 Engine speed sensor - no signal
16955/P0571 Brake light switch (F) - implausible signal
17653/P1245 Needle lift sender (G80) - short to earth
17654/P1246 Needle lift sender (G80) - Implausible signal
17655/P1247 Needle lift sender (G80) - Open circuit/short to positive
17762/P1354 Modulating piston movement sender (G149) - electrical fault in current circuit
17969/P1561 Metering adjuster (N146) - control difference
17978/P1570 Engine control unit blocked
18020/P1612 Control unit incorrectly coded
18026/P1618 Glow plug relay (J52) - short to positive
18027/P1619 Glow plug relay (J52) - open circuit/short to earth
18040/P1632 Accelerator position sender - voltage supply

mk4gasm · Sep 16, 2014

Bob_Fout said:
Inspect / clean the needle lift sensor wires and plug that are attached to #3 injector. Should have set a code of if it was that, though.

Thanks, I''l try this tomorrow when I have some free time.

whitedog said:
How about the throttle sensor?

I'm not sure what you mean, is it something I can clean/test?

RacerTodd said:
The flashing glow plug is sort of a super "check engine light". It flashes when the ECU detects that certain very important components are out of spec.

Per a post by MoGolf, the codes that cause a flashing glow plug light are below.

00741 Brake pedal monitoring - implausible signal
01044 Control unit incorrectly coded
16705/P0321 Engine speed sensor - implausible signal
16706/P0322 Engine speed sensor - no signal
16955/P0571 Brake light switch (F) - implausible signal
17653/P1245 Needle lift sender (G80) - short to earth
17654/P1246 Needle lift sender (G80) - Implausible signal
17655/P1247 Needle lift sender (G80) - Open circuit/short to positive
17762/P1354 Modulating piston movement sender (G149) - electrical fault in current circuit
17969/P1561 Metering adjuster (N146) - control difference
17978/P1570 Engine control unit blocked
18020/P1612 Control unit incorrectly coded
18026/P1618 Glow plug relay (J52) - short to positive
18027/P1619 Glow plug relay (J52) - open circuit/short to earth
18040/P1632 Accelerator position sender - voltage supply

The glow plug light doesn't flash constantly..it almost acts as if my engine stalls for a second because the glow plug light comes on for a quick second and my CEL turns off (racepipe) and then comes back on after 10-15 seconds. Maybe I should add that to the OP.

whitedog · Sep 16, 2014

You could check to see if the throttle position sensor is showing properly across the full range of it's movement.

But now I am wondering if you had a main power disconnect for a second. it shut off the power to everything then it came back on and lights came on then went off.

Dave_D · Sep 17, 2014

Has relay 109 ever been replaced? If it starts to go you will get drop-outs similar to what you are describing, as the ECU loses power for a few moments. You can get a new one for about $20, so it is no big deal to replace and may solve the problem.

Dave

mk4gasm · Sep 17, 2014

Thanks for the responses guys, it managed to do it again on the way home from work and I literally just finished running vagcom:

Address 01: Engine
Fault Found:
16786 - EGR System
P0402 - 35-10 - Excessive Flow - Intermittent
Readiness: 1 1 0 0 0

Address 15: Airbags
1 Fault Found:
00532 - Supply Voltage B+
07-10 - Signal too Low - Intermittent

Address 19: CAN Gateway
1 Fault Found:
01314 - Engine Control Module
49-10 - No Communications - Intermittent

The 01314 - Engine Control Module one I've never seen before....

mk4gasm · Sep 17, 2014

Dave_D said:
Has relay 109 ever been replaced? If it starts to go you will get drop-outs similar to what you are describing, as the ECU loses power for a few moments. You can get a new one for about $20, so it is no big deal to replace and may solve the problem.

Dave

It has not been replaced, I'll look into that after I check up a little on the code I just got. Thanks for the help!

mk4gasm · Sep 18, 2014

Well it looks like a good place to start is by replacing relay 109, I'm going to order one and I'll update the thread when I'm back in the country.

ALH RPM drop + glow plug light

mk4gasm

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Bob_Fout

Oil Wanker

whitedog

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RacerTodd

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mk4gasm

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whitedog

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Dave_D

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mk4gasm

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mk4gasm

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mk4gasm

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