Pls help me as I have battled hard starting for some months.all d mech I met are just guessing in their approach.

I scanned the car and it came up with the following code;

P0340 - Camshaft Position Sensor 'A' Circuit Malfunction
P1656 - Oil control valve circuit malfunction
P1663 - Oil control valve/variable valve timing RH bank malfunctionlfunction
P0141 - O2 sensor heater fault (bank 1 sensor 2)

Ireplaced the camshaft sensor but still no improvements

If it's a V6 you have 2 camshaft sensors.
Make sure you are changing the right one.
If you change the right one and it continues then your issue is timing related which is actually very likely since you have oil control valve codes.
Your timing chain/belt may have jumped a tooth

http://www.themazdaforum.com/showthread.php/5568-The-P0340-Camshaft-Position-Sensor-Circuit-Malfunction-Thread

check this forum.

Spoke with another mechanic and after listening to the engine sound, he said the timing was ok.
Now back to the OCV, is it thesame as the cam shaft sensor? Where is the ocv filter located in my Avalon xls? All the mechanics cant locate it.

Please someone help me out...

P0340 - Camshaft Position Sensor 'A' Circuit Malfunction
P1656 - Oil control valve circuit malfunction
P1663 - Oil control valve/variable valve timing RH bank malfunction
These codes related to hard starting...but may not necessarily be component malfunction. it reads "Circuit Malfunction" and may just be a wiring problem.
The last code has nothing to do with hard starting, but can impact on your fuel consumption greatly. The information you gave is scanty, i will need the following information:
At what time of the day do you have the hardstarting?
If it started did the engine run smoothly?
Have you ever done a compression test on the car before?
When last did you do a service? (I mean quality service? Quality service translate into four things 1. Genuine Materials, Skill personnel, Factory Procedures and Good Machines).
I am afraid some of these vehicles are sensitive to conditions of usage and maintenance.
Let me know your answers to the questions.

THanks Autoquint,

I recently did acomprehensive servicing . The hard starting happens at anytime of the day and sometimes it starts at one crank.

The runs smooth with ocasional lost of power when breaking and accelerating. It also misfire once a while.

How do I trace or troubleshoot the cam sensor wiring?.

I will say it one more time, your issue is timing related.
A mechanic cannot "listen" to an engine to determine a timing belt issue conclusively.
The OCV is in the timing belt cover area.
You can start by replacing it(pic posted below. If that doesnt fix then have an experienced tech open up the timing area to check for a jumped/extended belt and other anomalies.

@ Nisspart,
We checked the timing and it seems ok. I still checked for the ocv but didn't find it.

This is what we located. Am sure this is camshaft sensor. What do u think?[img][/img]

I cant open your link but ive already shown your what the OCV looks like.
You'll see the dark part with the connector sticking out of the timing cover.
As I said, listening to an engine will not give you an indication of a timing belt issue and the fact that your mech doesnt even know where the OCV is says it all.

nissparts: I cant open your link but ive already shown your what the OCV looks like.
You'll see the dark part with the connector sticking out of the timing cover.
As I said, listening to an engine will not give you an indication of a timing belt issue and the fact that your mech doesnt even know where the OCV is says it all.

I have corrected the attachment. The engine has two of those. Still check for the OCV myself with another mechanic but we didnt find any.

Thats the camshaft sensor and as i told you in my very first response, there are 2 on your engine and you should verify you even changed the right one

What i did this morning is to remove the two from another Avalon and tested it on mine but no improvment. the DTS code only shows P1656 and P1663 after clearing the codes, then after running the engine for some times, it shows P0340, P1656 and P1663.

Still cant find the OCV. So sad

Sigh, I guess I have to do everything for you. Luckily Im in a good mood

http://imageshack.us/photo/my-images/716/ocvj.jpg/

There are 2. One on each engine bank.

This is now getting intresting. Using the drawing provided, I search deeper and found two connectors just hanging but the ocv are not there. My mech suggested that probably the engine has been changed before but I doubt. No sign of any ocv point. It looks stupid but that is d reality.