Looking for some solid sound tech advice (preferably from someone with Volvo Experience) in regards to a 2006 Volvo 5.0GXI that is pulling a 342 Loss of Cam input signal code once running. Note: I work for a full service marina, we have 3 highly trained techs with 20years each in the Marine trade as well as automotive Licenses. There’s no lack of knowledge, but we have run into a problem leaving us at a loss. The History: A customer purchased a boat sight unseen from Florida and brought it to us not running with the above engine. It had no fuel pressure with key on or Cranking. Pump harness had power. Replaced the fuel pump and the engine fired right up, but ran very poorly and pulled the code listed above. Pulled the distributor cap off, bellow the cap was full of corrosion, also had original plugs and ignition wires. Performed and ignition tune up per the customer request, and also put a cam sensor in it becuase we had it all apart and the sensor is directly bellow the rotor. Fired it up, engine runs perfectly, but still pulls the Loss of Cam input signal code. Started diagnosing the cam code: first confirmed the distributor and rotor were in the correct orientation per the timing mark on the crank. (Flat top distributor, same as the Mercruiser 555ecm). Performed continuity test between the cam sensor signal wire and the pin on the ECM. Also confirmed 5v reference and ground is being supplied to the sensor. We also backprobed the Cam sensor plug and supplied a good ground, and backprobed both the ECM plug and the cam sensor plug and provided a jumper wire in the event that the signal wire possibly showed continuity, but had high resistance. When doing this, the engine actualy runs poorly. Scoped the Cam sensor siganl wire with its unplugged. Only seeing 0.3Volts. We believe this is a pull down style hall effect that should have 5 volts on the signal wire when unplugged. Scoped the signal wire with engine running. Square wave is supplied, but only between 0V and 0.3V. Here’s where it gets weird: Fire the engine up, and shut it down with the ignition switch. Try to restart it, and it won’t restart. Cranks, fires momentarily, and shuts down. Cycle the battery switch (cutting constant 12V power to the ECM) the boat will fire back up. Even with the Loss of Cam code still active. Other things we have checked: Crank sensor and wiring all good, Ignition module and wiring all good, correct wiring at the ignition switch. We also confirmed that instead of shutting the battery switch off and back on, if we simply pull the 20amp fuse supplying constant power to the ECM momentarily, the engine will start back up. Don’t kill power to the ECM, and it will not start after the key has been cycled. We have also confirmed the ECM has a good clean ground and 12 volts when cranking (14.2 when running) On our Techmate 2, When the engine is running, cam retard is showing 0 degrees. Spark advance is fine between 7-25 depending on RPM. Tach shows a proper RPM reading. Based on all the diagnostics, we called an ECM, which did NOT fix the issue. Has anyone ever run into this situation before?
Topic Author
