my car (SKODA OCTAVIA 2016 1.6TDI) has flashing glow plug light twice in 2 weeks. Car doesn't go into limp mode. Still drives normally. The cruise control shows it has error and got deactivated when the glow plug light flashes.

 

I have scanned with VCDS and saw this error code- P0572 - Brake Switch.

 

I checked the brake light still works normally when the error comes on. A restart of engine will clear the flashing light. Anyone able to share what is the part that I should change? Thanks.

There are two switches involved, one causing the brake lights to come on, the other one informing the engine ECU that the brakes are being applied. They're both in the same housing. The brake lights working doesn't prove that the other is, unfortunately.  

 

On your car I expect the switch(es) are on the underside of the brake master cylinder rather than at the pedal. The wire from the relevant switch going to the ECU may be a white/green one from pin 1 of the 4-way at the switch connector to ECU pin 21.  Access is not easy, I believe, on RHD cars.  I would be inspecting that wiring and connections prior to purchasing anything, if it were my car.

 

Edited 27 April, 20224 yr by Pete_Ex-Wino

4 hours ago, Pete_Ex-Wino said:

There are two switches involved, one causing the brake lights to come on, the other one informing the engine ECU that the brakes are being applied. They're both in the same housing. The brake lights working doesn't prove that the other is, unfortunately.  

 

On your car I expect the switch(es) are on the underside of the brake master cylinder rather than at the pedal. The wire from the relevant switch going to the ECU may be a white/green one from pin 1 of the 4-way at the switch connector to ECU pin 21.  Access is not easy, I believe, on RHD cars.  I would be inspecting that wiring and connections prior to purchasing anything, if it were my car.

 

thanks for the info. will definitely check out the wiring and connections. Are you referring to this switch #7 in the diagram?

 

Yep.

I wonder if the wording 'repair set' implies a known issue?? 

Those two part numbers seem to be equivalent, see all numbers near top:

Brake Light Switch Škoda 5G0698459 (skoda-parts.com)

 

Which is odd considering the price difference shown here LLLParts

 

Edited 27 April, 20224 yr by Pete_Ex-Wino

Hi Pete,

 

Would you know what do "Short to GND" means?

"Short to GND" means no voltage present where voltage expected - most common cause is a blown fuse, next most common is a broken wire or bad connection, least common is faulty component.

Could also be an actual short to ground, say from water having got into the connector and shorting pins together. Or a bit of loom wire with insulation worn away against some unpainted metal.

I have changed out the brake light sensor and everything has been working fine.

 

To change the sensor, there's a need to remove the coolant and brake oil expansion tank.