16787 - EGR Valve (N18) malfunction - something else to check

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hermanjirwin
Caddy2k Groupie
Posts: 5
Joined: Fri Jan 17, 2020 7:40 pm
Engine size/power: 2.0 SDI (70bhp)

16787 - EGR Valve (N18) malfunction - something else to check

Post by hermanjirwin » Thu Feb 13, 2020 4:33 pm

2007 Caddy 2.0 SDI. Lots of white smoke. Rough tickover and hard to start.
Reports 16686 Missfire and
16787 - EGR Valve (N18) Malfunction.
Looking at live data and could see the EGR spec was asking for 185mg/str and the actual was 460mg/str.
So thought I would start with the EGR. Stripped what I could and inspected. The online help I found said to check electrical connections and wiring, faulty N18 valve etc. I couldn’t see anything wrong so was considering replacing parts. Putting it all back together I nudged the servo pipe coming from the Vacuum pump. It fell apart revealing a split in the end of the pipe. Checked the other end at the servo and it was split as well. Haven’t had the caddy long, the brakes work fine but the pedal did go hard quite quickly after killing the ignition. Anyway, replacing the two pipes between the servo and the vacuum pump has removed the fault and brought the actual readings in line with spec. So, just something else to check when you’re looking for causal issues.