2000 4.7 P340 (camshaft sensor and multiple items tested)

I have a 2000 Tundra 4.7. I am getting a p340 code. I have tried searching and had no luck on what the issue could be. I recently replaced the timing belt, idlers, and tensioner. Everything ran fine for a month then pulling out of a parking lot the engine power was suddenly decreased, engine code, and the exhaust note changed. The exhaust sounds like it is "Dumping" on acceleration. I double-checked the belt it is not broken and the tension looks good. The truck is drivable but not great. Extended cranking time if driven, shut off for a min, and then started again. If sitting for a while it will start okay. Things I have tried are as follows.

* New camshaft sensor (old one tested good but figured why not)
* Wiring to the camshaft sensor.
* Getting a good signal voltage at the ECM (5v)
* The crankshaft sensor has good voltage at the ECM and the sensor tested good.
* The lobe on the camshaft pulley is good.
*Fuel pump circuit good including relay.

I have not tested the following but plan on it.
*Compression test
*Fuel Pressure test

Any ideas?

 

MAF sensor?

 

P0340 or P0430? Just asking since we had someone else on here recently say they were throwing a P0013 when it was actually P0031. There's a huge difference.

If it's P0340, which camshaft sensor did you replace? There are two, IIRC (hopefully I'm not confusing my engines here), and in the older trucks, there was a defect in the earlier years that led to damage to the wiring.

If P0430, if you've never replaced your catalytic converters, P0340/P0240 are cat inefficienty codes and typically triggered by upstream and/or downstream O2 sensor, normally upstream, but can also be downstream.

Always replace in pairs (upstream and downstream on the affected bank, in your case P0340 is bank 2/passenger side, whereas P0420

Only replace with Denso OEM, and DO NOT buy the parts from scAmazon or fleaBay or WallyWorld or AliBaba or similar. Buy from a reputable source, like Summit Racing or RockAuto. You'll pay less $$.

 

And just for a visual on what often happens with these sensors getting damaged, I pulled this thread up in about 2 seconds using the search function: https://www.tundras.com/threads/p0340-code-camshaft-position-sensor.95343/

It also has a handy PDF in reply #17 that will show you the layout of sensors.

 

Maf sensor is good.
It is a camshaft code. I did see there may be a second sensor. Where is the second one? The diagrams on Mitchel 1 only have the one on the driver's side by the cam under the cover. All testing is on the one sensor. Cats are new before I got the truck in August of 23. Not sure what parts were used though.

 

These trucks are super f'n picky with cats, and will continue throwing codes if you don't use a couple of specific brands. We've seen it countless times.
Likewise, the cats rarely go bad unless you had air/fuel issues, inefficiency codes are often result of O2 sensors slowly dying.

Can you confirm whether the code is P0340 or P0430?

 

Yeah it is a P0340.

 

Ok, well, I just remembered my confusion. BubbaW called me on this a couple times and I guess it still hasn't sunk in, aphasia is really fun! I've got a newer VVTi Tundra, and I think it typically throws Camshaft "A" and Camshaft "B" codes, suggesting two sensors, but the "B" sensor is actually one of the VVTi sensors. This was my confusion.

But anyway, that said ... little sanity check here...

Did you confirm the timing is good?

Did you confirm both cams have their tabs intact (see below)? Maybe this is what you're calling "lobe".

Did you confirm reference voltage on the camshaft position sensor? (pretty sure ours are 3-wire, one is reference, middle is ground, other is power?)

If no reference voltage, did you confirm there are no blown fuses in the engine bay fusebox?

Cam tabs I'm referencing, I remember seeing one mystery P0340 where these were smehow snapped off on both cam pulleys for a 2UZ and causing P0340:

​

 

I am using lobe incorrectly tab is much more accurate. I did check the driver and it is there. I’ll have to check the passenger.
If I remember correctly I am getting 5v ref all the time with to ECM. I’ll double check that.
I did make sure the timing marks were correct when the timing belt was done. I’ll have to go look again but I think I am currently getting around 10 degrees at idle.

 

Have you tried clearing the codes and see how long before it pops again?

I'm still choking on that 1 month of no code. You're 100% positive no rub-through is happening? Like this or this?

This video talks about testing the sensor at the harness itself, and testing the sensor with a nifty trick:

https://www.youtube.com/watch?v=KTTs4eHU-d0​

 

100% on the camshaft sensor tested both wires to the ECM and both have continuity and almost the same resistance. I need to check the two to the crankshaft sensor. Though getting good voltage to the ECM pin. I did swap the ECM with a used one same issues.

 

You've got me stumped, that's about all I got.

This is one of those cases where I'd be really tempted to - after double-verifying time, tabs, fuses, no wire nicks - to pay Toyota for 1-2 hours diagnostics to see if they can figure it out.

 

Agreed, I'll double check and post an update once I get that done. Thanks for all the replies I do appreciate being able to bounce ideas off someone.