What it means
Heated (electrically warmed) catalyst on bank 2 fails efficiency monitoring. In addition to standard catalyst aging, faults in the catalyst heater control or supply can cause this code.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The Bank 2 heated catalyst uses an electrical heater to help it reach effective operating conditions sooner. The engine control module monitors catalyst efficiency and heater-related operation, and P0433 sets when the heated-catalyst efficiency test falls below its threshold.
Common causes
Most likely first.
- Catalyst aged or contaminated
- Catalyst heater circuit fault
Symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
How to diagnose it
- Review freeze-frame and live data to confirm when the Bank 2 heated-catalyst monitor failed and whether the fault followed a cold start.
- Inspect the Bank 2 catalyst and exhaust joints for leaks, damage, or signs of contamination.
- Check the heated-catalyst heater wiring, connectors, and related supply connections on Bank 2 for heat damage, corrosion, or looseness.
- Use the manufacturer's procedure to check heater operation and control-circuit integrity, since a heater fault can affect catalyst performance.
- If the heater circuit and exhaust are sound, compare Bank 2 sensor data and assess the catalyst for lost efficiency.
Common fixes
- Repair an exhaust leak or damaged connection near the Bank 2 heated catalyst.
- Repair damaged heater wiring or a loose or corroded connector.
- Repair a confirmed heater control or supply fault.
- Replace the Bank 2 heated catalyst assembly if testing confirms it is inefficient or damaged.
Can I keep driving?
If the engine runs normally, gentle driving is generally possible, but emissions may be high and the vehicle may fail inspection. Avoid heavy load if there is a strong sulfur smell, and address the heater or catalyst fault promptly.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.