Rattle on start & Error P0391 Cam Shaft Sensor

[irelandbuyer]

All,

Wondering if this has happened here before.

Car was rattling on cold last week, was OK when it warmed up. Nothing else for the rest of the day.

The following day, the Emmissions Light came on so I brought it to my local independent who ran a diagnostic and it threw up the following fault:

"Fault Code: P0391/Cam Shaft POS Sensor.Bank 2"

We're going to swop this to the other side and see if the problem follows it and if so, then replace the sensor. Hopefully it's just a sensor but the concern of the technician is that this is actually a deeper issue with the timing chain and he feels it's an early warning that something else is amiss..

I read elsewhere that you can see from the readings if the timing chain is elongated?

Wondering if anybody has heard of this fault code etc?

Cheers.....

[Mechcanico Lee]

Originally Posted by irelandbuyer

All,

Wondering if this has happened here before.

Car was rattling on cold last week, was OK when it warmed up. Nothing else for the rest of the day.

The following day, the Emmissions Light came on so I brought it to my local independent who ran a diagnostic and it threw up the following fault:

"Fault Code: P0391/Cam Shaft POS Sensor.Bank 2"

We're going to swop this to the other side and see if the problem follows it and if so, then replace the sensor. Hopefully it's just a sensor but the concern of the technician is that this is actually a deeper issue with the timing chain and he feels it's an early warning that something else is amiss..

I read elsewhere that you can see from the readings if the timing chain is elongated?

Wondering if anybody has heard of this fault code etc?

Cheers.....

Which engine , petrol , diesel ...... does it have variable timing control cams
The rattling maybe suggests stretched timing chain so yes you would get the code you have .
To check the cam /crank synchronisation with out a strip down you need to scope cam and crank signals and compare to a known good waveform trace .

Thinking about it if in the data blocks you have relative cam angle to crank , yes you could see from this if the chain is stretched

[matt]

When you say rattle on cold for how long.

I only ask as my 4.2 petrol 06 d3 has just started rattling for about 3 secs when its not been run for a few hours.

Only had it a few weeks, Seems like i Have a few issues under the hood that have just developed. have to top up water every 3 days. The guy must have had a good way of disguising faults as they didnt do it for the first few weeks lol.

Gonna trawl some threads and see if i can diagnose

[Mechcanico Lee]

Originally Posted by matt

When you say rattle on cold for how long.

I only ask as my 4.2 petrol 06 d3 has just started rattling for about 3 secs when its not been run for a few hours.

Only had it a few weeks, Seems like i Have a few issues under the hood that have just developed. have to top up water every 3 days. The guy must have had a good way of disguising faults as they didnt do it for the first few weeks lol.

Gonna trawl some threads and see if i can diagnose

Very often the rattle from cold for a few seconds is a stretched timing chain , the hydraulic tensioner has to wait for the oil pressure to fully extend it , the 3 second rattle is the time it takes to build the oil pressure .
Also check that it has a genuine or at least a good quality oil filter , if it's a spin on filter they have a one way membrane on the filter inlet , this is there to hold oil pressure in the oil filter to help with the no oil pressure from start scenario .

[matt]

Originally Posted by Mechcanico Lee

Very often the rattle from cold for a few seconds is a stretched timing chain , the hydraulic tensioner has to wait for the oil pressure to fully extend it , the 3 second rattle is the time it takes to build the oil pressure .
Also check that it has a genuine or at least a good quality oil filter , if it's a spin on filter they have a one way membrane on the filter inlet , this is there to hold oil pressure in the oil filter to help with the no oil pressure from start scenario .

This was my thought thanks for the second opinion.

I am going to do an oil and filter change i think.

It sort of coincides with an oil top up i did.

Never trust the guy at the car shop lol... maybe i topped up with wrong oil perhaps.

[Mechcanico Lee]

Yes try the oil and filter change , but if it still has the start up rattle looks like you may be in for a much bigger job I'm afraid