P0340 code (complete shut down) and need some advise

Hi Everyone,

Long time browsing and great website for Subaru info.

My car:

2009 Legacy (special edition), 2.5i na, 5MT.

All OEM, 116k miles and running great until yesterday.

(had timing belt, plugs, coil pack, wires done at 105k)

Car completely shut down while on the fwy doing 75mph (no prior warning or hesitation) and wouldn't crank over or start on the side of the fwy. Had it towed home and read just a P0340 code (camshaft position sensor).

After charging up the battery (2 yrs old) a little, the car barely cranked over and backfired.

Read that a P0340 code usually would put you in a limp mode, and maybe doesn't restart. Also read that when a motor completely shuts down (and doesn't restart), it could be a bad crankshaft sensor (P0335 code), but I only had the P0340 code.

Pulled both the camshaft sensor and crankshaft sensor out and measured good resistance of 2k ohms for both. Cable harness grounding measured good on both.

Please correct me if wrong, but a 2009 2.5 na (SOHC) only has one camshaft sensor on the driver side just behind the front timing cover, right? I read that turbo 2.5i or earlier motors had two camshaft sensors. Interesting that a P0340 code is for passenger side (bank 1) but the only one sensor is on the driver side (bank 2).

Next step - if both camshaft and crankshaft sensors measuring good and the wiring seems ok, I'll clean the sensors, re-install them, clear the code, reset ECU (10 sec ignition on before starting) and see if the car will start.

Not sure if with cleared codes, will another code(s) appear by just cranking the motor w/o it actually starting?

My concern is that maybe the motor timing skipped a tooth (even though new belt 11k ago) and if I start cranking it over, I might cause damage (bent valves, etc..).

Thanks in advance for any response.

Richard

If it did jump while you were driving the damage may already have been done.

Remove valve covers and check timing first. When that's done - check the compression. If both checks out then it's probably only the sensor that died.

And if it has jumped it's not necessary that it did cause problems so get the timing right and do a compression test.

Please correct me if wrong, but a 2009 2.5 na (SOHC) only has one camshaft sensor on the driver side just behind the front timing cover, right? I read that turbo 2.5i or earlier motors had two camshaft sensors. Interesting that a P0340 code is for passenger side (bank 1) but the only one sensor is on the driver side (bank 2).

Not sure if with cleared codes, will another code(s) appear by just cranking the motor w/o it actually starting...

My concern is that maybe the motor timing skipped a tooth (even though new belt 11k ago) and if I start cranking it over, I might cause damage (bent valves, etc..)...

P0340 is usually used to indicate a fault in the sensor or the wiring (i.e. open circuit or short circuit). There is a P0341 DTC that indicates the readings from the camshaft position sensor don't match what's expected.

I would check all wiring/connectors thoroughly to rule that out. Check wiring between the sensor and ECU, and also the engine grounds. I think you are on the right track.

If you want to be safe, you can turn the motor over slowly by hand, using a breaker bar on the crankshaft. Stop if you feel any resistance. You can also remove the timing cover, but that is more work.

Thanks ehsnils & MilesA

I figured P0340 was a generic code and doesn't mean just the camshaft sensor.

I reinstalled same sensors and tried starting the car. With a fully charged battery, it cranked slow, never caught up to start and had a small backfire. The battery drained a lot for just cranking over the engine twice for 10 sec. No hard mechanical interference that I could tell but it cranked very slow.

I don't think it's a harness or grounding issue, but a mechanical off-timing issue.

Tomorrow, I'm going to remove the front timing covers and inspect the Gates belt, tensioner, sprockets, etc and also try to check the compression.

Thanks for the inputs