Hello
Have a 99 Discovery V-8 auto 80,000 miles.
Need help, have a 1138 code coming from the reader.
All I can come-up with is: HO25 failed to switch to lean, Bank "A"
What does this mean-any ideas were to start ?
Any help will be appreciated.
Thanks,
Rm Andre

For some reason, you're running rich on one bank, or at the very least, the ECU thinks it is running rich.

What is the realtime output of the O2 sensor, bank A vs bank B?

mechanic....but this is all new to me back A / back B.
What is meant by back A and B ?
And how do you read realtime output of O2 sensor?

Thanks for the time/help.
Rm Andre

The Rover fuel injection management sytem controls the fuel injectors one side of the engine versus the other.

Reading realtime output of the sensors-your OBDII software should allow you to see the outputs of the various sensors as the engine runs so you can look for glitches in either the sensors or the control computer. The oxygen sensor outputs will toggle between rich and lean as it makes minute adjustments to the pulse width of the signal going to the injectors.

If you have a factory workshop manual or better yet, the Rave CDs, some reading on the theory of operation for the engine management system will serve you well.

Thanks for the help, will do the research in this area and
see what I can come-up with.
Thanks.