Car problem question:

This 2002 Hyundai Accent has a cam sensor code: P0340. We tested the 3 wire terminals of the cam sensor and for some reason, the cam sensor signal wire (white black) does not have a voltage reading at KOEO. To verify, we disconnected the sensor and the reading remains open. Do I replace the ECM?

ATS Adviser:

That cam sensor signal wire should have a fluctuating voltage when engine is running. It is either 0-5 v or 0-12 v depending on the engine rpm. If no reading at all, its an open connection between pin 2 at cam sensor to pin 79 at ECM. To verify, measure resistance between those 2 points and expect to get 0.2 to 0.4 ohm to see if the wire is connected. If higher than 5 ohms, it is shorted, if infinite ohm reading it is open. You can also run a jumper wire on the same points and see if the problem stop. Note: when doing resistance (ohm) test, disconnect car battery.

Shown below is a typical 2002 Hyundai Accent cam sensor wiring:

2002 Hyundai Accent cam sensor wires

For more details, you can get a complete wiring diagram for this vehicle from most parts store when you buy parts or get it free online when you join ATS.

It's a miracle! I found the open ECM wire (pin 79) like what you said. Reconnected and sealed the wire and the car problem is fixed!

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