P0439 Volvo Catalyst Heater Control Circuit Bank 2

P0439 Volvo Catalyst Heater Control Circuit Bank 2

Possible causes
– Catalyst Temperature Sensor harness is open or shorted
– Catalyst Temperature Sensor circuit poor electrical connection
– Faulty Catalyst Temperature Sensor
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
P0439 Volvo Description

The Engine Control Module (ECM) monitors the switching frequency ratio of heated oxygen sensors 1 (front O2 sensor) and heated oxygen sensors 2 (rear O2 sensor).

A three way catalyst converter (Manifold) with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. As oxygen storage capacity decreases, the heated oxygen sensor 2 switching frequency will increase.

When the frequency ratio of heated oxygen sensors 1 and 2 approaches a specified limit value, the three way catalyst malfunction is diagnosed.

Volvo Vehicle:Volvo C70,Volvo S40,Volvo XC90,Volvo XC70,Volvo XC60,Volvo V70,Volvo V50,Volvo V40,Volvo S90,Volvo S80,Volvo S60
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