Powertrain, generic · Auxiliary emission controls
P0433 Heated Catalyst Efficiency Below Threshold Bank 2
Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo
An electrically heated catalyst has a heating disc ahead of a support catalyst so that it works soon after a cold start (Emitec EMICAT, 12–48 V); it was tried on Californian petrol cars in the 1990s and is used today mainly on diesels, for example Audi's 3.0 TDI from 2014 and 48-volt diesel vans. P0433 means the heated catalyst of bank 2 (the side without cylinder 1) no longer converts enough; CARB requires it to be assessed like any other catalyst. No manufacturer document available to us uses this code.
Likely causes
Heated catalyst aged or poisoned
Heater not working, catalyst active too late
Sensor used for the assessment faulty
Calibration (Ram: software update per bulletin)
Symptoms
- Check engine light on
- Higher emissions after a cold start
- Otherwise usually unremarkable
Repair estimate
DifficultyHardWorkshop job
Parts and labour€150–3,000
Time0.5–4 h
Typical range across vehicles; the real cost depends on what the testing finds.
Parts involved
electrically heated catalystcatalyst heaterengine control module
Related codes
References: law.cornell.edu, emitec.com, dieselnet.com.