P0488 fault code

[GruffLion]

Evening all,

I have an HDi in limp mode with a P0488 fault code. It looks like an EGR problem. The car is on 138k miles if that assists. I have tried the easy option of spraying a can of cleaner into the inlet just downstream of the inter cooler without luck. What do I try next - EGR off for a deep clean? I should add that the car does the infamous ‘fart’ on shutdown.

 

[Pedro]

P0488- EGR Throttle position control/range performance discrepancy Check the MAP sensor is clean & is in one piece also P1161 can sometime appear which indicates MAP & EGR problems as in carbon build etc

 

[GruffLion]

P0488- EGR Throttle position control/range performance discrepancy Check the MAP sensor is clean & is in one piece also P1161 can sometime appear which indicates MAP & EGR problems as in carbon build etc

Thanks Pedro,

I have stuck a new MAP sensor in but no Luck - it is still throwing codes.
using my cheap as chips OBDii dongle and iPad I can see both manifold pressure and throttle position graphs as the engine runs. However the throttle position seems to start somewhere in the mid 40% Range at tickover and drop when I rev; is that normal behaviour?
Im not quite sure where to go next - TPS if the behaviour above is not right I guess?

 

[GruffLion]

Thanks Pedro,

I have stuck a new MAP sensor in but no Luck - it is still throwing codes.
using my cheap as chips OBDii dongle and iPad I can see both manifold pressure and throttle position graphs as the engine runs. However the throttle position seems to start somewhere in the mid 40% Range at tickover and drop when I rev; is that normal behaviour?
Im not quite sure where to go next - TPS if the behaviour above is not right I guess?

Don’t worry - I have finally found the issue ( with assistance from YouTube) and it’s a daft one. Basically on the throttle body but hidden on the engine side there is a plastic linkage that is a push fit onto its’ shaft - it had fallen off…

 

[Pedro]

I remember putting a screw in the arm on one of those for someone they are a pain as the linkage wears & they just disconnect themselves the other one to watch is the flap inside the housing which can also cause problems

 

[GruffLion]

I thought I would share some pics of what I found with the throttle body removed. Hopefully this may assist someone in the future.

As you can see the hole in the end of the vacuum actuator arm has worn down to the point where it has almost broken right through - no wonder it fell of the crank pivot. What a poor bit of engineering.

 

[Pedro]

Yep that's the culprit a truly piss poor design for a component that has to work its bollocks off to keep the car moving !