This car has recently had a (second) head gasket replacement. The quality of workmanship is very poor. Silicon sealer in great big globs, rounded off fasteners, complete inability to diagnose failed ignition lead despite big burn mark on the side etc. I did ask the customer if the job was done by a family member or a "professional" and apparently she paid good money for the work, but when she got it back it was misfiring and the engine light was on. We wonder why we get a bad name!
To the problem:-
P0340 returns immediately Which Autodata decodes as "CMP circuit problem". I told customer that I could fit a sensor or spend time diagnosing. The answer was fit a sensor. Problem remained so out comes the scope, trace attached.
It certainly looks to me as if the CMP signal is late in relation to the crank signal. Does anyone have a known good trace for this engine,or information on which edges should sync?
I do find it frustrating that the code is listed as "circuit fault" and not "cam/crank synchronisation error" or a different code given for this fault. Unless of course this trace is correct and the ECM cannot see the cam signal at all. Customer feedback suggests no MIL before headgasket replacement.