Helge

I left my 2001 LS430 to a certified independent Toyota shop to replace the VSV for ACIS stuff which was throwing an error code.

It came back with that fixed and the code gone, but with a camshaft position sensor error code combined with a VCT error code.

I understand that the VCT error is normal with a check engine light and will probably go away when the camshaft error is fixed.

However, despite having the same shop change both cam sensors and swap them from side to side, the cam sensor error refuses to go away, and the shop has run out of ideas.

The engine is sometimes hard to start, so it behaves as if there really is a cam sensor error, not just a confused computer.

Ideas on what could be wrong? Most likely, the shop messed something up when doing the intake job, e.g. damaged a cable...

Tom57

What codes are you getting? Is it possibly the VVT oil control valve that is the problem? Since it's an '01, the oil control valves could be failing.

Helge

It is code P0340.

tcr101

iTrader: (2)

A code P0340 could mean one or more of the following has happened:
- Faulty Camshaft Position Sensor
- Camshaft Position Sensor harness is open or shorted
- Camshaft Position Sensor circuit poor electrical connection
- Faulty starter motor
- Starting system circuit
- Dead (Weak) battery
(http://engine-codes.com/p0340_lexus.html)


I got lucky with mine, it was only the sensor. If its hard to start, is it possible your battery is dying?

Helge

Replaced the battery to eliminate that potential problem.

Arcturus

Check the wiring harness on the sensor. First check visually for any cuts or kinks in the wiring. Then examine the plug pins for damage or discoloration.

I'm not sure if there's a sub harness for this sensor, but if you can find both ends of the plugs check for an open connection. Put the multimeter on both ends of the same wire of the plug and check for high or infinite resistance with your multimeter.

If someone can post the circuit diagram we can try and find where in the branch a possible fault could lie. I went through this same issue with a wheel speed sensor and replaced it only to find the same error message - it turned out to be a burned out harness plug.

Also check whether there are any fuses on this circuit that may have burned out.

Arcturus

Are these camshaft positions sensors factory or aftermarket?

rkw77080

Here's what the repair manual says about P0340...

Tom57

What parts exactly DID the Toyota dealer replace?

Helge

Factory from Sewell and that place in California. In original Toyota packaging.

Helge

Since the parts are cheap and I did not know whether the valve or the actuator was bad, I had the shop replace both:

VALVE ASSEMBLY, INTAKE AIR CONTROL, 1730050010

ACTUATOR, INTAKE AIR CONTROL VALVE, 1733550011

GASKET, INTAKE FLANGE, 1711650010

Helge

Since swapping over the sensors from bank to bank has not made the problem go away, it points to cabling (or ECU).

Arcturus

I would strongly suggest examining the wiring in detail before condemning the ECU. They seldom go bad.

Might also want to check the resistance of the cam sensors themselves and compare with the factory specs just to be sure.

rkw77080

Here's the inspection procedure for the Variable Valve Timing (VVT) sensors...



Please note that VVT Sensors are not the same as Camshaft Position Sensor

Helge

Far-fetched idea: are the VVT and Camshaft sensors identical? I.e. could the shop have replaced the wrong sensor?

(I remember they have talked about doing work on on the intake side when replacing the sensors. From the picture, it looks like the cam sensor is on the front side of the cylinder head, facing the grille. The one cam sensor I have tried to replace myself was on a Mercedes V8, facing the grille but behind a couple of belts...)