204ps suddenly lagging

[swd80]

We have a 2017 204 ps DSG LWB Caravelle which we've had since May. The engine was running fine until today when it has been seriously lagging. I notice that when cruising, the kickdown needs a big push on the accelerator and it's similar when setting off from a standstill. This has literally just started today.
Any ideas?

 

[Loz]

Loss of boost
faulty maf sensor
manifold flap
DPF clogged

any warning lights?
you need to scan it really.

 

[swd80]

No warning lights. No fault codes when scanned with Torque app connected to a Carista dongle.
Watching the realtime data in Torque I can see a real lag between throttle and boost.

 

[swd80]

The issue went away but back today (with the wet weather? ).
Glow plug light on dash started flashing.
Scanned again and got:

P0402 – Exhaust gas recirculation (EGR) system -excessive flow detected​

 

[DXX]

Just had a look at Ross-tech codes and does look like the egr is playing up


16786/P0402/001026 - Exhaust Gas Recirculation (EGR): Excessive Flow
Possible Symptoms

• Malfunction Indicator Light (MIL) ON
• Reduced Exhaust Gas Recirculation (EGR)
• Reduced Power Output/Engine running rough
• Increased Emissions

Possible Causes

• Exhaust Gas Recirculation (EGR) Valve stuck open/leaking/faulty
• Exhaust Gas Recirculation (EGR) System leaking/faulty
• Wiring and/or Connector(s) from/to Exhaust Gas Recirculation (EGR) Valve faulty

Possible Solutions

• Check/Clean Exhaust Gas Recirculation (EGR) System
• Check/Replace Exhaust Gas Recirculation (EGR) Valve
• Check Wiring and/or Connector(s) from/to Exhaust Gas Recirculation (EGR) Valve

Possibly a split EGR pipe, plenty of cases, common fault.

 

[swd80]

Now the code has changed to

P0403 – Exhaust gas recirculation (EGR) -circuit malfunction​

 

[mmi]

Torque app connected to a Carista dongle.

Perhaps you could use app "Car Scanner" (free version) with Carista dongle and read engine fault codes again - curious to see what Car Scanner reports.

1st tip - for T6 use Connection profile Volkswagen > OBD-II/EOBD Diesel DPF var. 1.​

2nd tip - tick only engine for fault code reading (much faster than scanning all controllers (possibly even non-existing))​

​

Now the code has changed to

P0403 – Exhaust gas recirculation (EGR) -circuit malfunction​

Did you get flashing glow plug light for this?

 

[swd80]

Sometimes I get a flashing light, sometimes not. It has settled down a bit now and I'm getting full power most of the time.
It's gone into the garage today and they say that because of the electrical code it's showing it'll need a whole new EGR unit. Quoting close to £1K with parts and labour

 

[Loz]

Sometimes I get a flashing light, sometimes not. It has settled down a bit now and I'm getting full power most of the time.
It's gone into the garage today and they say that because of the electrical code it's showing it'll need a whole new EGR unit. Quoting close to £1K with parts and labour

If it's jammed open yes, but have they ruled out damage(chafing) of the loom to the EGR sensors?

 

[swd80]

They don't seem that confident to do anything with it like that. They said that even to take it off for a clean would be a couple of hours labour and they think it's not worth it. I might take a look for an EGR expert locally who could sort it out for less money.