My 04 G35 AT (100,000 miles) threw code P0021, Intake valve timing solenoid Bank 2. Past owner had replaced bank 2 Timing solenoid, Cam sensors and Crank Sensor with after market. I could see plenty of threads on this problem and after market sensors seem kind of iffy. I replaced Bank 2 Cam sensor and Crank Sensor with Infiniti parts purchased on-line. Oil (Mobil 1 Synthetic) is clean, new filter and topped off. Same code was thrown again. I checked oil pressure and all is well. I removed oil pan, no sludge and pick up clear. Replaced the o-ring behind oil filter housing while I was there. I replaced Bank 2 Intake Valve Solenoid (factory part). Still throws same code. The car idle is smooth, no knocks, pings, or any undue sounds. The timing chain is quiet. Gas mileage is around 18 mpg. Car starts and turns off easy.

I am going to add some Lucas Oil Treatment with the next few changes but I really don't know my next step.

I know there is an after market Cam Sensor in Bank 1. Could a bad Bank 1 Sensor have anything to do with a code on Bank 2?

I'm not sure what else to look at. Is this the point where I give up and take to dealer for diagnostic? I know they get better detail on codes and sensors. Any advice is welcome.

 

Here is a step to check:


INSPECTION AFTER INSTALLATION
Inspection of Camshaft Sprocket (INT) Oil Groove
CAUTION:
● Perform this inspection only when DTC P0011 or P0021 are detected in self-diagnostic results of
CONSULT-II and it is directed according to inspection procedure of EC section. Refer to EC-125,
"SELF-DIAG RESULTS MODE" .
● Check when engine is cold so as to prevent burns from any splashing engine oil.
1. Check the engine oil level. Refer to LU-7, "ENGINE OIL" .
2. Perform the following procedure so as to prevent the engine from being unintentionally started while
checking.
a. Release fuel pressure. Refer to EC-81, "FUEL PRESSURE RELEASE" .
b. Disconnect ignition coil and injector harness connectors.
3. Remove intake valve timing control solenoid valve. Refer to EM-100, "CAMSHAFT" .
4. Crank the engine, and then make sure that engine oil comes out
from camshaft bracket (No. 1) oil hole. End crank after checking.
WARNING:
Be careful not to touch rotating parts (drive belts, idler pulley,
and crankshaft pulley, etc.).
CAUTION:
Engine oil may squirt from intake valve timing control solenoid
valve installation hole during cranking. Use a shop
cloth to prevent the engine components and the vehicle. Do
not allow engine oil to get on rubber components such as
drive belt or engine mounting insulators. Immediately wipe
off any splashed engine oil.
● Clean oil groove between oil strainer and intake valve timing control solenoid valve if engine oil does not
come out from camshaft bracket (No. 1) oil hole. Refer to LU-4, "LUBRICATION SYSTEM" .
5. Remove components between intake valve timing control solenoid valve and camshaft sprocket (INT),
and then check each oil groove for clogging.
● Clean oil groove if necessary. Refer to LU-4, "LUBRICATION SYSTEM" .
6. After inspection, install removed parts.
Inspection for Leaks
The following are procedures for checking fluids leak, lubricates leak.
● Before starting engine, check oil/fluid levels including engine coolant and engine oil. If less than required
quantity, fill to the specified level. Refer to MA-10, "RECOMMENDED FLUIDS AND LUBRICANTS" .
● Use procedure below to check for fuel leakage.
– Turn ignition switch “ON” (with engine stopped). With fuel pressure applied to fuel piping, check for fuel
leakage at connection points.
– Start engine. With engine speed increased, check again for fuel leakage at connection points.
● Run engine to check for unusual noise and vibration.
NOTE:
If hydraulic pressure inside timing chain tensioner drops after removal/installation, slack in the guide may
generate a pounding noise during and just after engine start. However, this is normal. Noise will stop after
hydraulic pressure rises.
● Warm up engine thoroughly to make sure there is no leakage of fuel, or any oil/fluids including engine oil
and engine coolant.
● Bleed air from lines and hoses of applicable lines, such as in cooling system.
● After cooling down engine, again check oil/fluid levels including engine oil and engine coolant. Refill to the
specified level, if necessary.

 

Thanks, looks easy enough. I will not get a chance until this weekend or next but that looks like a good place to start.