The HEATER CIRCUIT MALFUNCTION error means that the built-in heater inside
the sensor has failed. The only recovery from this is to replace the
affected sensor. Having said that, this is not an error that should result
in your car shutting down.

The sensor works when it has reached a certain temp. This temp will easily
be reached through the passing of the exhaust stream, but the rise-time is
too slow. The computer wants to see a valid input faster than exhaust stream
will heat the sensor -- the problem here is that the sensor is needed to
reduce smog, and a cold sensor will not reduce smog so they heat it by
internal means to get it to work. The internal heater is broken.

Neither code you reported should shut the car down. Of the two, the second
might result in the car reverting to Limp Mode, where it runs crappy -- and
rich (too much gas is fed).




> wrote in message
ups.com...
> My son has a 98 Escort GT. 2.0, the check engine light has been on
> for a while with the code P0141 02 Sensor Heater Circuit Malfunction
> (Bank 1 Sensor 2), but the car still ran ok. Just recently the car
> started fine and he drove about 1/4 mile and the engine quit, it would
> not accelerate. Once the car cooled off it would start again and do
> the same thing. I checked the codes again and an additional code was
> there (PO136), which was the 1st o2 sensor. I changed the 1st sensor
> and the code went away, but the car still has the same problem it
> shuts off after a 1/4 mile or so, the 2nd code is still there. If I
> change the 2nd sensor will this fix the problem or could something
> else be causing the car to stop?
>