No readings from lambda on 4.0 thor

Hi all, my range rover 4.0 thor p38,has just got back from diagnostics,and came up with lambdas not reading at all. Readings were 0.0. Does anyone know what might cause this?

There are two pairs of Lambda sensors on Californian (US too?) spec cars, UK cars only have the (pre cat?) lambdas, a numpty who doesn't know what he's doing might look at the wrong Lambda readings - the unfitted pair still exist according to the Engine Management Software software and show up as dead lambdas on my generic OBDII reader.

This was done by a 4x4 landrover specialist,have had the same machine put on it before, when i had problem before it was just 1 lambda that was slightly out so replaced both sides,now 6 months down the line no readings from none of them.

StuckAgainSteve said:

There are two pairs of Lambda sensors on Californian (US too?) spec cars, UK cars only have the (pre cat?) lambdas, a numpty who doesn't know what he's doing might look at the wrong Lambda readings - the unfitted pair still exist according to the Engine Management Software software and show up as dead lambdas on my generic OBDII reader.

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Thought the Later P38's had 4, pre & Post cat Lambdas (2 on each branch)...!!

Does anyone know where the wires go and if there is any fuses to the lambdas?As my rangey is now really lacking power and need it for work.

Do you have RAVE....??

Grad a copy here Manuals

just tried to download it ,but have no discs to burn it onto.

PDF Version - pdf Land Rover Manuals | Landroverweb.com

Online Version - Land Rover Workshop Manuals

Get under the car and read direct from the sensor with a multimeter. Connect to the black wire and look for a reading of .8 v rich to 0v lean changing about every 1 second. As mentioned the uk spec cars only have pre cat sensors although the motronic Ecu will register the missing ones but show a zero values. Did you get any reading from the Mac and check for air leaks.

Thought '99 on THORs had 4 Sensors....

My 99 Thor 4.6 only has two pre-cat lambdas.

Thor have only 2 if its a uk model,the us spec have 4, so i have been informed via the guys at landrover.still my truck is'nt working could bothe lambdas go at the same time?or is it worse than that.please help i'm stuck.:drama:

finch range rover fan said:

Thor have only 2 if its a uk model,the us spec have 4, so i have been informed via the guys at landrover.still my truck is'nt working could bothe lambdas go at the same time?or is it worse than that.please help i'm stuck.:drama:

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Unlikely, they tend not to fail completly but rather get lazy. I would look at the ECU plug, look for signs of water ingress / corrosion on the pins.

Had a quick look earlier,could'nt see any water or corrosion at the end where the lambdas plug into.could the ecu have failed? if so would a 4.6 one fit?

finch range rover fan said:

Had a quick look earlier,could'nt see any water or corrosion at the end where the lambdas plug into.could the ecu have failed? if so would a 4.6 one fit?

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Yes, they are the same.

do i have to have it matched to the the bcem?if so could it be done by myself?

Also a fellow member said have i got any readings from the mac,could someone please tell me what this is.Many thanks.Also could it be my mass air flow sensor?After going through loads of posts people say they have had readings of 0.0v.Having looked at mine it is not the original one as i can see it is not a bosche one .

Did you check the Ecu plug in the ebox next to the bulkhead, right hand side looking at the engine ?

finch range rover fan said:

Does anyone know where the wires go and if there is any fuses to the lambdas?As my rangey is now really lacking power and need it for work.

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Engine ECM, Ignition Coil and Oxygen sensor have a some fuse in the Bonnet. it is 10A. I do not remember what number the fuse.

Before you get too carried away with wiring diagrams etc,had it occured that they might be reading zero for a reason ? You say its flat and lacking power,that could be because its running too lean.Motronic engines are prone to this due mostly to low reading Mafs not allowing a wide enough injector pulse width.