Time for another diagnosis and repair
This time on a 2007 ’57’ 1.9 CDTI Vauxhall Zafira MPV sporting just under 50K
The owner has just had some issues with vehicle, after a recent repair at another garage, the cars service / Engine check light was coming on
This was put on the Maxi code reader knowing its pretty good at diagnosing Vauxhall cars
P0400 – EGR (exhaust gas recirculate) Flow Malfunction
I’ve had this fault code appear on another Vauxhall beforehand (Astra 1.3 version – solid with carbon build up).
To ensure it wasn’t “just a blip” it was cleared, to see if the code re-occurred like I suspected it would.
A Short time later the vehicles lights were back on, with the same P0400 code.
Since the car was pretty much sure the EGR was problematic, I suspected it was most likely gummed up with carbon deposits causing the mechanical valve inside to be stuck.
Strip down time – Since the Zafira has a large engine bay, the engine sits nicely inside, but the opening of the bonnet isn’t as great….. So making it a little harder to get my club hands in to remove the valve
After Removing 3x Longer Anchor bolts, 1 electrical connection and 4x Pipework bolts the EGR valve was pulled free!
So away I went using a screwdriver to scrape all the gunk and hard carbon deposits out of the valve to enable to some flow of gasses.
The valve physically couldn’t open as the carbon build up inside was so bad; it couldn’t compress and allow any flow of the gas.
So time later with a toothbrush and a can of brake cleaner, the majority of the gunk was pulled out, leaving a visible improvements
Using a socket and a hammer, the valve was operated till it was free to operate by hand
Next the electrical side of the valve was looked at – removing the small amounts of carbon present from the spacer gasket and the little actuator rod
Slight problem been the valve was fully retracted inside the actuator – meaning I was unable to ensure it could move freely, as I didn’t have the diagnostics equipment to carry out actuator tests. This caused me the concern that it may result in the fault code re-occurring due to been a failed actuator.
Rebuilding the EGR valve, the attention was pulled to the pipework that the EGR uses.
The Return from the EGR to the Intake wasn’t as bad as the EGR, but still coated in oil and carbon, a quick spray with cleaner and wipe out removed the majority of the gunk.
The feed to the EGR from the exhaust system wasn’t able to be cleaned as well due to no-access. Using a screwdriver and spending some time, the gunk was removed to help improve the flow of exhaust gases to the EGR valve.
All back together, followed by a code clear, the car was sent back on its way with the owner, in hopes the actuator was able to operate the valve properly. Should the code return; the valve will simply need to be replaced and another attack of the feed pipe to pull the gunk out.
However – now the valve can work, it may now be able to pull sufficient of the exhaust gasses to give its desired effect of cooling the combustion chambers temperature
bbautorepairs 