vectra c

[radiosolutions]

04 reg, 1.8l, it is runnuing erratic when started. plugged in opcom keeps coming up with crankshaft sensor "a" open circuit,replaced sensor with genuine vauxhall new, i have checked wiring from sensor to ecu,all is fine. does this mean ecu is faulty. thanks

[oldford]

What's the number from the fault code?

[radiosolutions]

What's the number from the fault code?

p0335 crankshaft sensor "a" open circuit m8

[oldford]

I would check the signal with a scope. Maybe the wiring picks up some interference.
Also check trigger wheel. All teeth present with the correct height?

[Scopepattern]

also check engine valve springs are not broken,this is a known issue at this age of vectra,also camshaft sensors can still throw up crank codes.Has the timing belt tension been checked,a loose timing belt can cause crank/camshaft phase issues.

[radiosolutions]

just to let all no, the problem was the wiring. the chap who owned the car had another engine fitted and the crankshaft sensor and the oil sensor were the same plugs,so were fitted wrong. has the crankshaft sensor was grey and the oil sensor black,he automatically thought the grey plug went to the crankshaft sensor and the black to oil sensor,but this is wrong the black plug went to crankshaft, all is running perfect now. hope this helps. thanks for all your info

[autoelectric]

Thanks for the feedback m8.

[racin-snake]

the good bit in this story is one point overlooked
try the old sensor for actually being open circuit if not next test is volt drop wiring from ecu
as an ohmeter will show continuity but will it carry the load or signal ?
then ecm last
a scope s great when required but this fault in actual fact could have been found with just a dmm and a code much earlier
all in all its a great fix but also a lesson in reading the code correctly then having the strategy to deal with the fault logically

[BRAVO6]

, i have checked wiring from sensor to ecu,all is fine.

Fair play for putting up final solution, but this is a lesson to people to check wiring correctly. If you had consulted a diagram and check the ECU pins for crank sensor, then you would have seen that wire colours were wrong