Flashing Glow Plug Assistance (000741, 00750)

I've got the flashing glow plug issue from the above two codes:

00741 - Brake Pedal Monitoring
00750 - Warning Lamp: Open or short to ground

Glow plug light goes off when the brake pedal is pressed, but comes back on again a couple minutes later.

I've researched both and can't seem to resolve this problem by doing what is called for to resolve both codes. I've also noticed cruise control doesn't work (I purchased a new cruise control switch but haven't installed yet)

- all brake lights work (no led bulbs)
- changed glow plugs, harness, relay, all rear lights
- changed both brake switches (blue and black) and recalibrated both plungers

Another note, I had gotten pretty deep into trouble shooting but can't remember where in VCDS I was checking for brake pedal 000/010 monitoring. 0 would change to a 1 when pressing the brake pedal. I do recall one of them was showing a 1 when it should have been a 0. Or was it vice-versa...

Any assistance would be greatly appreciated.

The brake switch has two sets of contacts, one for the brake lights and one for the cruise control. A failure of either one triggers a flashing glow plug "fix me now" MIL warning, and given your symptoms it sure sounds like it's the cruise control side of the switch that's gone south.

Normally I am not a big fan of shotgun troubleshooting, but in the case of flashing glowplug lights and brake switch codes I'd suggest just replacing the switch and see if it fixes things...they are cheap and the job is quick.

One of those "by the time you read 10 random internet suggestions you could have already fixed it" kinda things.

What kind of brake bulbs do you have? I had the same problem on mine, come to find out, someone had put led brake light bulbs in.

Edit: noticed you stated no led bulbs... be sure they are the right number bulb though, there are several that fit, but some don't have the right resistance.

Sent from my S60 using Tapatalk

I do have LED headlights. I hope and assume this isn't the problem.

I'll try swapping out all the tail lights today as there were there before I purchased the vehicle.

Headlights are not monitored on that circuit.

Added brand new 7528 brake light bulbs, problem persists.

Any other ideas? I’m sure I’m not the first to have this specific problem...?

Perhaps I missed it... have you replaced the brake light switch... ie... maybe you got a dud the first time? Where did your new switches come from?

Another option, track down someone with VCDS and you can explicitly monitor both sides of the brake switch.

I was thinking about replacing the switches, again.

I have VCDS but I don't recall the module I was in that monitored the 0's and 1's in real time while pressing the brake pedal.

Might you know?

Can't remember off the top of my head, but Ross Tech's site will have the info.

It's one field with multiple bits, and there's one bit each for the two brake switch contacts and a third for the clutch switch IIRC.

So... after replacing all the tail light and all brake switches, I found the problem after a year of troubleshooting a flashing glow plug light and the codes above. I had also purchased a cruise control switch to replace for when I did the heater core and flap rehab, but couldn't find where to replace the switch. Reason being, the car didn't have cruise control and I had mistakingly replaced with a cruise control stalk when I removed the steering wheel. The fix was simply disconnecting the cruise control stalk harness connector and problem solved. I just have to replace the stalk with a non cruise control one. I have it.

Oreganoflow said:

So... after replacing all the tail light and all brake switches, I found the problem after a year of troubleshooting a flashing glow plug light and the codes above. I had also purchased a cruise control switch to replace for when I did the heater core and flap rehab, but couldn't find where to replace the switch. Reason being, the car didn't have cruise control and I had mistakingly replaced with a cruise control stalk when I removed the steering wheel. The fix was simply disconnecting the cruise control stalk harness connector and problem solved. I just have to replace the stalk with a non cruise control one. I have it.

Click to expand...

That's a very strange situation, was your car a regular US import? All mk3 Jetta TDI cars had cruise as standard equipment so I don't know why the switch removal would solve your problem unless the replacement switch you removed was faulty.

This is a very curious situation.

Steve

My car doesn't have the cruise control silver box next to the white box behind the light switch, so I'm assuming it never came with cruise control.

Oreganoflow said:

My car doesn't have the cruise control silver box next to the white box behind the light switch, so I'm assuming it never came with cruise control.

Click to expand...

TDI doesn't require separate cruise module (silver box), the ECU handles the cruise function and because the car is DBW it is a much cleaner setup.

Steve

Ah damn. How do I know if I have it then?

Pretty sure all TDIs have cruise as standard... 'cause it's just a few extra lines of software plus the clutch, brake, and stalk switches.

Oreganoflow said:

Ah damn. How do I know if I have it then?

Click to expand...

Like Vince (and I before) said, all Mk3 Jetta cars (starting 1995) had cruise control as standard equipment. At least for US import (and probably Canada too).

It was standard in 1993 on Jetta GLS and in 1994 on GLS and GLX too.

You have it, you just need the correct stalk.

Steve

Interesting... I'll find another stalk and see if that one works without codes. Thanks everyone for your help.