My car has been slightly miss fireing and I have today changed the air flow sensor and although the car is running better i still have a slight misfire in lower gears, i cleared the error codes but after a 10 min drive i re -tested, and the codes P1646 and P1647 where back.

The codes are Linear 02 Sensor Control Chip Bank 1, and Bank 2?

I believe these to be sensor on the excaust system bank 1 (Passenger side) and Bank 2 (drivers side)?

Surely both have not gone at the same time? Hence why i have changed the Air flow meter as the only thing i can think off that would cause this is a lean engine air/fuel mixture?

can anyone give me guidence on what to check next?

 

Those codes are for the lamda sensor heater circuit according to JTIS. That would indicate either some ECU problem (hope not!), ground circuit (inspect where th sensor ground connects) , or MAYBE a blown fuse in the heater circuit.
Post the MY and model, and I will look up which fuses to look at.

 

Jaguar XKR, 2000 model,

Although this morning i have driven the car and it drove perfectly, I think it may have been that it needed a cold start to re-set the engine management system. but i'm still getting the error codes.
Thanks

 

I dunno. Those are pretty specific code to the heater control circuit and the implication is that they are generated by the ECU based on current flow.
Do you have a CEL? Did you reset the codes with the scanner? By disconnecting the battery?
In any case, good luck and repor back how it comes out.

 

Just been out in the car and now only one of the wornings are coming up, I'm now hopeing it is just taking time to clear our the system.