P0165
System
Powertrain (Emissions)
Scanner required
Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)

O2 Sensor Circuit High Voltage (Bank 2 Sensor 3)

Understand P0165, common causes, and the right SEAFLO pump to diagnose it.

Bank 2 sensor 3 O2 circuit voltage high or open.

Common symptoms

  • Check engine light
  • Poor economy

Typical causes

  • Open O2 sensor circuit
  • Failed sensor
  • Connector unplugged after exhaust work

What scanner do you need?

Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)

Use live data and freeze frame to confirm the fault before replacing parts. ABS, SRS, and network U-codes usually require a full-system scanner.

Diagnostic tips

  • Record freeze frame data when the code first sets
  • Clear the code only after fixing the root cause
  • Check for related pending codes that point to a common issue
  • Verify battery voltage is above 12.4V before chasing sensor codes

Frequently asked questions

Can I diagnose P0165 with a basic code reader?
P0165 may set in the engine module, but related diagnostics often benefit from an enhanced or full-system scanner with live data and freeze frame.
Is it safe to drive with P0165?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.