Polo TDI 6R - glow plug feed voltage

[DIYspanner]

2011

Glow plug light on the dash is flashing.

All three glow plugs have about 1Ω resistance so seem good.

I put the multimeter on one of the glow plug's feed wire and switching on the ignition, showed 11.75v for about two seconds then dropped to 2v for a while, then zero.

Faulty glow plug relay perhaps?

 

[Belle427]

Sounds normal to me if close to battery voltage.
The glow plug light flashing usually points to another issue so I'd code read it first.

 

[Burnerman]

As above, the voltage is correct.......it drops low according to ambient temperature which in turn affects the glow plug timer.
Sometimes the glow plugs aren’t energised at all, sometimes they come on even if the engine is running!
The flashing lamp indicates other engine issues - it’s very much generic so out with the code reader.
John

 

[DIYspanner]

I'll get the code reader plugged in.

 

[DIYspanner]

P00AF code

Doing some investigation on YT, I discovered that the little one way valve that's piped between the vacuum pump and turbo boost pressure valve was not allowing any vacuum to the turbo boost pressure valve so the turbo's actuator wasn't operating, hence the glow plug warning light was flashing.

Blew through the one way valve and got it freed up. Have been out for a drive and the turbo's performance is very much improved and no flashing glow plug light. If it happens again, I'll fit a new one way.

 

[Belle427]

Good result.