2004 L322 4.4L V8 misfire on cylinders 1-4 but OBD code P0156 is Bank2 Sensor2 fault

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22nd February 2018, 08:10 PM
Pedro_The_Swift

thinking by bank,,
If the thermo is not working, would the cold water in bank 1 cause missing, by the time the coolant has passed through bank one its warm enough for bank two to operate?

hard pressed to think of another reason an entire bank would miss,,
22nd February 2018, 08:52 PM
PLR

It`s a bypass system where the engine and heater matrix system are used on initial start so other than what is in the block from cold the engine block , heads etc themselves are always heated .

On initial there is no flow through the radiator etc

The firing order probably masks the fact that one bank misses other than at low revs .

When it does what it does would be important and what the engine check is doing going out at revs would say somethings not right low down . The check norm would be to come on or blink or stay on .

The lack of drivability suggest limp but most things of cause will code , the O2 could do it and light the engine check other sensors etc should code but they have not but things don`t always act as expected .

Self would first be checking vacuum and air leaks etc vacuum pipes , PCV system as with Martys , inlet gasket , throttle gasket etc charging the battery , checking exhaust for leaks all for elimination .
22nd February 2018, 09:50 PM
PLR

Quote:

Originally Posted by cuz

Thank you for your help.
Although the 1- 4 cylinder misfires are on a single bank, shouldn't that bank be Bank 1 and not bank 2 as indicated by the P0156 fault code?

Best regards, Cuz

Didn`t look at it properly till just now sorry .

P0156 is RH bank rear O2 signal circuit malfunction ( drive side )

RH bank is cylinders 1-4 ( drive side )

If you swap O2s right to left and read code with a P0136 outcome the O2 in the now left probably need replacing .

If no code shows you may have had a poor connection or similar .
25th February 2018, 07:18 AM
cuz

Quote:

Originally Posted by PLR

Didn`t look at it properly till just now sorry .

P0156 is RH bank rear O2 signal circuit malfunction ( drive side )

RH bank is cylinders 1-4 ( drive side )

If you swap O2s right to left and read code with a P0136 outcome the O2 in the now left probably need replacing .

If no code shows you may have had a poor connection or similar .

That's great info and tip thank you PLR. Will do. Rgds, Cuz
25th February 2018, 07:28 AM
cuz

Quote:

Originally Posted by PLR

G`day ,

don`t know , depends on the cause could be 2 things the missing won`t necessarily affect O2 reading enough to register/log a fault .

The O2 telling what it is doesn`t necessarily mean it`s broken they can be tested .

Is the rough idle all the time or is it hot or cold , when does it happen .

Is the light on with the rough idle or doesn`t it matter , what revs or speed does it extinguish and does it come back on or stay off , till restart or what .

Where did you find the definition P0000 code as thermostat at best that i can find it`s suggested it`s a code to say no faults logged or a pass code .

Below is a pdf if it works it`s a manual for L322 only thing is it for the USA , CAN .MEX market so has some differences .

You will find test procedure of O2s , P codes etc , most is there

http://www.landroverweb.com/Pdf-file...ge%20Rover.pdf

Thanks for the advice and pdf.
The light is only on with the rough idle. At normal driving revs it goes out and comes back on again at idle. Also, the steering starts to squeal at rough idle when stationary. I assume that's because there's not enough revs for the power steering to operate normally.
The P0000 code and all other code definitions are from the Carsoft i930 diagnostic tool I used to assess the faults.
25th February 2018, 10:10 AM
PLR

Thanks .

You may want to check that the fluid level for the power steering is in range .

Rough idle and PS squeal could relate to the idler or one of the tensioning pulleys trying to seize or any of the rotating bits the belt runs on if the squeal is the belt .

The AC has its own belt and tensioner

If the rough idle and squeal persist after you`ve had a look at the O2 you may want to take the belt off and see that all spin freely .

With help you could just relax tensioner to give enough belt slack to spin each if you`d prefer not removing the belt but the route of the belt is in that pdf

By the way the pdf is the correct right hand drive one and not the other US Canadian one though it does cover some of their stuff .
26th February 2018, 04:12 PM
cuz

Quote:

Originally Posted by PLR

Thanks .

You may want to check that the fluid level for the power steering is in range .

Rough idle and PS squeal could relate to the idler or one of the tensioning pulleys trying to seize or any of the rotating bits the belt runs on if the squeal is the belt .

The AC has its own belt and tensioner

If the rough idle and squeal persist after you`ve had a look at the O2 you may want to take the belt off and see that all spin freely .

With help you could just relax tensioner to give enough belt slack to spin each if you`d prefer not removing the belt but the route of the belt is in that pdf

By the way the pdf is the correct right hand drive one and not the other US Canadian one though it does cover some of their stuff .

Thank you PLR,
Power steering fluid is clean and level is good.
O2 sensor sockets and fan clutch nut wrench kit came today, so I'll attack all parts as suggested in the coming days.

Thanks again and best regards, Greg (Cuz)
26th February 2018, 05:51 PM
p38arover

Quote:

Originally Posted by Pedro_The_Swift

and electric thermostat?
or am I reading that wrong?

The thermostat is conventional but with an electric heating element to open it further if the need arises.

My M62 now has a conventional thermostat. The electric bit is not there and the wiring is disconnected.

Over the past weekend during a tour (with a motorcycle group) mine stated to misfire quite often and badly and occasionally brought on the engine check light. When I was able to, I connected the diagnostic tool and saw multiple misfire but only on no.1 cylinder. I cleared the fault and the car was OK for most of the remaining trip into Canberra. I cleared it again last night ready for today's trip home.

It stumbled a couple of times today but when I got home and had a look, no faults had been logged. Nevertheless, I swapped the coils between 1 & 2 cylinders and will monitor it to see if there are any more faults logged.
28th February 2018, 04:04 PM
cuz

Quote:

Originally Posted by p38arover

The thermostat is conventional but with an electric heating element to open it further if the need arises.

My M62 now has a conventional thermostat. The electric bit is not there and the wiring is disconnected.

Over the past weekend during a tour (with a motorcycle group) mine stated to misfire quite often and badly and occasionally brought on the engine check light. When I was able to, I connected the diagnostic tool and saw multiple misfire but only on no.1 cylinder. I cleared the fault and the car was OK for most of the remaining trip into Canberra. I cleared it again last night ready for today's trip home.

It stumbled a couple of times today but when I got home and had a look, no faults had been logged. Nevertheless, I swapped the coils between 1 & 2 cylinders and will monitor it to see if there are any more faults logged.

Thanks for the additional info Ron,
I've now removed, cleaned and swapped over both left and right downstream oxygen sensors. As previously suggested, I now have the fault on the opposite bank with error code on my iCarsoft i930 of P0136 ( bank 1 downstream sensor) where as I previously had error code P0156 ( bank 2 downstream sensor).
I conclude that the O2 sensor is faulty and will be replaced. While I'm at it, I will replace both downstream sensors and let you know how I get on.

Thank you everyone for all your helpful suggestions.
Best regards, Greg (Cuz)

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