P0429 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.
Possible causes
- Catalyst Heater Control harness is open or shorted
- Catalyst Heater Control circuit poor electrical connection
- Faulty Powertrain Control Module
×