Have you found a solution to the problem?
Well i m coming back after a long time..
I did some tests with a voltmeter and a ohm meter. at the lambda cables
the 2 front lambdas and the back.
when the engine get start the 2 white cables having 12 volt signal to get warm the heater. after a few seconds the exhaust get hot and the ecu stops the signal at the 2 front lambdas.
the question here is ..
how the ecu undertand that the excaust is hot? from the signal that is coming back from the grey and black wires? (counts the oxigen?)or from the resistants of heater? as hot it is so the resistants gets higher.
so i did the same think and at the back
i connect the voltmeter at 2 white cables and i drive the car for 10 km.
all the excaust should be hot after this. but the ecu is still giving 12 signal at the heater!!! why is that?
maybe the ecu see from the oxigen sensor signal much co2? and thinks that the back catalisator is still cold? and not working properly?
why then doesn't give the message
P0139 O2 Sensor Circuit Slow Response (Bank 1 Sensor 2) or
P0138 O2 Sensor Circuit High Voltage (Bank 1 Sensor 2) or
P0137 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 2) ?
and gives always
P0141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
P0136 O2 Sensor Circuit Malfunction (Bank 1 Sensor 2)
my catalyst is a 200 cpi..
and i have remove the prokatalist..
i think that the ecu get stuck and give always signal the heater as much resistans the heater has.