Diagnostic trouble code P0155 on Volkswagen vehicles — what it means, the common
causes, and how to confirm the real fault before replacing parts.
What does P0155 mean?
P0155 indicates: O2 Sensor Heater Circuit (Bank 2 Sensor 1).
This relates to the Fuel & air metering system.
Common causes of P0155
oxygen sensor heater failure preventing rapid warm-up of sensor ceramic to operating temperature
What to check (live data)
oxygen sensor heater operating temperature (target approx. 1652°F / 900°C)
Parts often involved in P0155
oxygen sensor heater (Z19, Z28, Z29, Z30)
Don't replace parts until the root cause is confirmed — many of these codes are caused by wiring, a connector or an upstream fault, not the part itself.
Get the confirmed root cause for P0155 — on YOUR vehicle
A code is a symptom, not a diagnosis. AutoDX Pro cross-checks several
independent assessments, pinpoints the actual root cause, gives you the
exact tests to confirm it, and shows the parts — only after the cause is
confirmed. Reads your scan-tool photo and decodes your VIN with open
recalls.
P0155 is a diagnostic trouble code: O2 Sensor Heater Circuit (Bank 2 Sensor 1).
What are the common causes of P0155 on a Volkswagen?
Common causes include: oxygen sensor heater failure preventing rapid warm-up of sensor ceramic to operating temperature. The exact cause depends on the vehicle — confirm it before replacing parts.
Can I keep driving a Volkswagen with P0155?
It depends on the fault and your symptoms. Some causes are minor, others can damage components or affect safety. Get the root cause confirmed before deciding.
How do I fix P0155 on a Volkswagen?
Confirm the actual root cause with targeted tests first, then replace only the part that's at fault. AutoDX Pro gives you the root cause, the exact tests, and the parts for P0155 on your specific Volkswagen.