What Does P0433 Mean?
The heated catalytic converter on bank 2 is not achieving the required conversion efficiency. This code applies to systems with electrically heated catalytic converters that use heating elements to bring the catalyst up to operating temperature more quickly. The heating function or the catalyst itself is underperforming. The driver will see the MIL but may not notice driveability symptoms.
Common Causes
40%
Degraded heated catalytic converter catalyst material
25%
Failed catalyst heater element not bringing converter to temperature
15%
Wiring or connector issue to the catalyst heater circuit
12%
Rear O2 sensor degradation providing false efficiency readings
8%
Catalyst contamination from engine oil or coolant
Diagnostic Steps
1
Check the catalyst heater circuit — measure heater element resistance (typically 2–15 ohms depending on design). An open circuit or very high resistance indicates a burnt-out heater.
2
Verify power and ground to the heater circuit at the connector — with KOEO, there should be battery voltage on the supply wire when the PCM commands the heater on.
3
Monitor catalyst efficiency using front and rear O2 sensor waveform comparison at steady 2500 RPM — rear should be flat and stable if the catalyst is functioning.
4
Measure exhaust temperature upstream and downstream of the heated catalyst with a pyrometer during warm-up — the heater should bring the catalyst to light-off temperature (600°F+) within 30–60 seconds of cold start.
5
Inspect for the root cause of catalyst degradation — check for oil consumption, coolant leaks, and chronic misfire history that could have damaged the converter.
Estimated Repair Cost
$500 - $2,500
Parts + labor, varies by vehicle and location
The heated catalytic converter on bank 2 is not achieving the required conversion efficiency. This code applies to systems with electrically heated catalytic converters that use heating elements to bring the catalyst up to operating temperature more quickly. The heating function or the catalyst itse...
The most common cause of P0433 (Heated Catalyst Efficiency Below Threshold (Bank 2)) is: Degraded heated catalytic converter catalyst material
Typical repair costs for P0433 range from $500 to $2,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive. This is an emissions system efficiency concern. The vehicle will operate normally but will not meet emissions standards. Prolonged driving with a degraded converter could lead to downstream exhaust system heat damage in severe cases.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0433 to identify the root cause.
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Quick Info
Category
Powertrain
System
Exhaust / Catalytic Converter
Difficulty
Type
Generic (SAE)
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