error code p1138

Hi guys,

managed to get my bluetooth OBD2 scanner to comunitcate with the ECU on my 4.0 gems P38 today and its brought up a fault code.

Using a cheapo ebay item and the free "Torque" app on my phone. pretty impressed with the results to be honest!

P1138 Lack Of HO2S12 Switch - Sensor Indicates Rich

Now its been pinking on the what sounds like the drivers side of the block under load. feels a little underpowered and getting poor fuel mileage. All this started after a waterpump failure on the driveway. engine got warm but not in the red as it popped as we pulled up and I got it switched off before anything major!

Live data reading show bank 1 sensor 1 voltage changing as we drive but bank 1 sensor 2 at 0 volts unless thrashed to death then it suddenly picks up!

The fuel/air app shows it switching from closed to open to closed all the time.

From all this info can we deduce a knacked O2 sensor or could it be something else?

MAF has been exchanged for a known good item, Fuel pressure reg also been done

Decided I should really stop just throwing parts at it and figure out whats what.

Cheers for any help

Nobody?

I think you answered your own question - seems like a dicky Lambda sensor....

Thanks saint.
Just wanted to be sure and ask for some expert advice before just lobbing bits at it to be honest.

Cheapest way would be to swap them over and see if the error follows. Then you will know if its the O2 sensor or something darker.....

Beautifully simple idea! Bloody annoyed now that I didn't think of that myself as I do it all the time at work!

Time to go break some spanners!

I've had six now , every penny counts.....