Hi
i have a 2003 2.1 x type and i have the code p0037 coming up on my code reader i have changed the down stream lambda sensor and reset the codes but the dash light as come back on and its still reading p0037 does anybody have any ideas what it could be. I have read on the net it could be a relay. Any help would be gratefull

kelv

 

forgot to ask how many downstream sensors are there on the car i have a 2.1 petrol x type

 

Bank 1 sensor 2 is the black (not gray) connector sensor on the catalytic converter by the FIREWALL, NOT by the radiator, as everyone seems to think.

 

 

You have 4 sensors; two in front of and two after each catalytic convertor.

The first think to check for that "heater low" error is the fuse for the upper sensor; someone will chime in shortly with the fuse number (in the fuse box under the bonnet).

The heater elements will stretch as they grow older, sometime sagging far enough to contact the case internally; that will waffle the fuse in short order.

Eventually, the heater element will break like a light-bulb filament, which does mean that the sensor needs replacing.

Also, make sure your replacement is the Denso; other brands (Bosch, for example) have a different heater resistance and may show bad even though they are not.

 

It's an 8 year old thread too.