P0096 fault code
Discussion
Hello,
My Nissan Xtrail 1.6dci tow barge has thrown a P0096 code. ( I used a cheap diag tool to plug into the OBD2 port). It means that the IAT2 air temp sensor is displaying a value more than 10 deg different to other sensors. In this case the ECU provides default temp of 70F. However as the ECU can only see 70F it won't complete a regen of the DPF, which obviously can be a serious issue.
It is a known fault on this car, with the dealers just continually replacing the sensor - which doesn't get to the route of the problem. It has only occured on my car in the last month (90k miles from new/ full service history) because of the cold weather and it sitting on the driveway most work mornings, idling to clear the frost.
Drive routines are 5 miles ea way daily, urban but very little traffic, and 2x per month long journeys, including towing the race car. So it does normally get enough of a run.
Symptoms - eggy smell. (over fuelling I believe) , DPF/CAT can't handle the excess fuel so sulphur dioxide is in excess and can't be burnt off. Cruise control doesn't work. The latter is only related to the failure of the sensor in order for the driver to recognise there is a fault with the vehicle. Theoretically a technician should see that the Cruise doesn't work and link it to a faulty IAT.
The IAT sits downstream of the throttle body, and upstream of the air mass meter. All of those components are next to each other, at the front of the engine. It sits on top of ( with the sensor inside) an inlet tube.
My first action was to clean the sensor. I did this with some brake cleaner, and everything went back to normal again, no fault codes, cruise working, regen working. However after about a week, the faults came back.
Second action - test for resistance and also test a new spare I'd ordered. Both show as working, ambient value 2.2, hot value ( using hair drier) 0.6, re clean the sensor.
As the sensors appear to work, and as they appear dirty ( oil) when not working, my third action was to remove the TB, clean it, and do the same to the inlet pipe - the theory being that a dirty inlet pipe was sucking muck onto the IAT. It certainly was dirty, but not excessive ( although I don't know how bad it can get and still work).
Took the car for a test drive... it's probably ran the best it has in ages - stop start working, good fuel economy, felt like it had the power it should have.
However - do I think I've got to the route cause of the problem? No I don't think so.
Does any one have any other ideas I can look into, for if ( when ) the fault comes back?
My Nissan Xtrail 1.6dci tow barge has thrown a P0096 code. ( I used a cheap diag tool to plug into the OBD2 port). It means that the IAT2 air temp sensor is displaying a value more than 10 deg different to other sensors. In this case the ECU provides default temp of 70F. However as the ECU can only see 70F it won't complete a regen of the DPF, which obviously can be a serious issue.
It is a known fault on this car, with the dealers just continually replacing the sensor - which doesn't get to the route of the problem. It has only occured on my car in the last month (90k miles from new/ full service history) because of the cold weather and it sitting on the driveway most work mornings, idling to clear the frost.
Drive routines are 5 miles ea way daily, urban but very little traffic, and 2x per month long journeys, including towing the race car. So it does normally get enough of a run.
Symptoms - eggy smell. (over fuelling I believe) , DPF/CAT can't handle the excess fuel so sulphur dioxide is in excess and can't be burnt off. Cruise control doesn't work. The latter is only related to the failure of the sensor in order for the driver to recognise there is a fault with the vehicle. Theoretically a technician should see that the Cruise doesn't work and link it to a faulty IAT.
The IAT sits downstream of the throttle body, and upstream of the air mass meter. All of those components are next to each other, at the front of the engine. It sits on top of ( with the sensor inside) an inlet tube.
My first action was to clean the sensor. I did this with some brake cleaner, and everything went back to normal again, no fault codes, cruise working, regen working. However after about a week, the faults came back.
Second action - test for resistance and also test a new spare I'd ordered. Both show as working, ambient value 2.2, hot value ( using hair drier) 0.6, re clean the sensor.
As the sensors appear to work, and as they appear dirty ( oil) when not working, my third action was to remove the TB, clean it, and do the same to the inlet pipe - the theory being that a dirty inlet pipe was sucking muck onto the IAT. It certainly was dirty, but not excessive ( although I don't know how bad it can get and still work).
Took the car for a test drive... it's probably ran the best it has in ages - stop start working, good fuel economy, felt like it had the power it should have.
However - do I think I've got to the route cause of the problem? No I don't think so.
Does any one have any other ideas I can look into, for if ( when ) the fault comes back?
Edited by Dynion Araf Uchaf on Sunday 26th February 13:39
An Update.
I bought a new genuine IAT.
However before fitting it, I recleaned the old IAT using brake cleaner, then cleaned the inlet tube, then took the car on a 2 hour drive towing the race car, but keeping the revs high at 3k rpm to force a regen of the DPF. Problem gone, and not come back since.
I haven't needed to install the new IAT.
I did however remove and clean the EGR valve, it needed doing but I've seen a lot worse.
Interestingly I now have a theory as to why Diagnostic 'forced regens' only partially work, as I think you have to clean the IAT for it to work completely.
So the answer ( for all those R9M diesel engines throwing fault P0096 fault codes), clean the IAT, long run at 3k rpm, maybe clean the EGR and it's fixed.
I bought a new genuine IAT.
However before fitting it, I recleaned the old IAT using brake cleaner, then cleaned the inlet tube, then took the car on a 2 hour drive towing the race car, but keeping the revs high at 3k rpm to force a regen of the DPF. Problem gone, and not come back since.
I haven't needed to install the new IAT.
I did however remove and clean the EGR valve, it needed doing but I've seen a lot worse.
Interestingly I now have a theory as to why Diagnostic 'forced regens' only partially work, as I think you have to clean the IAT for it to work completely.
So the answer ( for all those R9M diesel engines throwing fault P0096 fault codes), clean the IAT, long run at 3k rpm, maybe clean the EGR and it's fixed.
Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff