99svtvenom

Hey guys, I have a 1998 LS 400 and have a PO340 code, the scanner tells me that its a camshaft position sensor. From reading it looks like these cars have two camshaft sensors and I was trying to figure out which one it is because they are a bit pricey and I didn't want to pick up the wrong one. Also will this PO340 cause the car to have a hard time starting? i.e. turning the key 3 or 4 times for it to fire up?

Tizzymack

I also have the same issue. I had my timing belt and water pump replaced because my timing belt had jumped a tooth. After it was completed I get the P0340 code. I'm going to order a sensor Monday and see if that corrects the issue.

andyman32

Yes, although I should issue the same caveat emptor as I do every time I offer advice here, I'm pulling from experience with engine management systems on other cars; but here goes.

The camshaft position sensor is primarily concerned with startup timing sequence. If the sensor is returning odd values or not functioning, the ECU will use default ignition timing tables which may or may not match "reality". It's virtually guaranteed to cause strange, labored startup behavior.

Once the engine has caught and is running normally, there is a crankshaft position sensor that runs engine timing. This is usually a sensor mounted to the front of the engine that "hovers" about 1mm away from the outer rim of the harmonic balancer. There will be a bunch of teeth and one gap. I believe the gap faces the sensor when the engine is at TDC.

I'm afraid I will have to leave it to the folks more experienced with the 1UZFE to tell why there are 2 cam position sensors, and if so, which one to replace. If there is just one sensor on each camshaft (as there may be), a rudimentary way you could check is to remove one or the other and crank the car, see if it makes any difference whatsoever. If one has failed, disconnecting the other one will probably cause the car not to start at all.

Good luck!