po340 fault code

[Gazz2311]

car in question is a 2003 arosa 1.0 mpi keeps throwing out this code which is cam shaft sensor open circuit . . Tried a few things to fix it like check the timing marks line up which they do tested the wiring to the sensor getting 12volts on one wire other wire think its the signal wire 5 volts and the other not sure whats its for earth ? replaced the sensor with a genuine one makes no difference car starts and drives no problem only problem i got is engine light stays on any help would be much appreciated thanks .

 

[ArosaRacer]

could be the breather blocked causing the cam sensor to throw a hissy fit

 

[Gazz2311]

Dunno still thinking it's a wiring fault 3 wire on that sensor getting voltage at two but am not sure what the other wire is doing i have been trying to find a wiring diagram but having no luck . Is there any marks on the cam shaft for the sensor to read it . Think that will be next job rocker cover off and inspect the cam shaft will also check breather's

 

[silver surfer]

3rd wire is earth for sensor

 

[Gazz2311]

That's what i thought its getting a 12 volt feed a 5 volt feed at signal wire
And its getting an earth. Light still on and still showing same code timing was
Checked again its spot on. Its had a brand new sensor fitted as well makes no
Difference cant get the light to stay off. Have no idea now what's causing it

 

[MJ]

Check the wiring from the ecu for short circuits or resistance. Open circuit denotes a break in the circuit.

It could be wiring or the ecu itself.

Or if the fault erases when the engine is not running but is stored as static when it's running then it could be the sensor ring on the crank and it's slipped causing timing correlation issues that the ecu flags as an open circuit fault.

 

[Gazz2311]

Would it not show a crank sensor fault up on the diagnostic computer ? . light was re set on Saturday again it run all day with light off even after a few re starts after coming out off shops . Sunday morning started it and light came on instantly. But car still drives perfect no loss off power it's as smooth as can be .