P223F: O2 Sensor Reference Resistance Out Of Range (Bank 2)

P223F is the reference-cell resistance check for the front wide-band sensor of bank 2. GM's 2016 and 2018 tables translate the measured resistance into element temperature and count readings below 700 °C or above 1,000 °C; 64 of 80 samples (2018) or 128 of 160 (2016) at 25 ms set a Type B code. The monitor waits for heater warm-up plus 20 s and is blocked while the bank 2 heater codes P0050-P0052 or P0155 are present, so a pure heater fault shows up there first. A reading that is too cold despite a working heater points to a sensor whose ceramic has aged and become high-resistance; too hot suggests overheating, for example from misfire. Bosch's LSU 4.9 data sheet gives 300 ohms as the nominal cell resistance. P223E is bank 1, P223D the pump-current check of the same sensor.

Bank 2 is the side without cylinder 1, so it only exists on V or boxer engines.

Symptoms

• Check engine light after two drives
• Bank 2 lambda control slow to become active after a cold start

Most likely causes

• Bank 2 sensor ceramic aged and high-resistance
• Weak heater supply or high resistance in the heater wiring
• Sensor overheated by misfire or very high exhaust temperature

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the wiring and connector of the sensor indicated
2. Compare the reading with other engine data while varying the engine speed.
3. Look for exhaust leaks
4. Check the signal in live data with the engine warm
5. Check the fuse and the heater resistance if the code mentions it
6. Replace the sensor if it has power and does not respond

Good to know

• Repair difficulty: medium
• It affects emissions.

What each character of P223F means

• P: Powertrain: engine and transmission
• 2: Generic code: same on every make
• 2: Fuel injection
• 3F: Specific fault in that system

Frequently asked questions

Can I keep driving with code P223F?

Yes, you can normally drive in moderation, but get it repaired soon: you will use more fuel and the catalytic converter can be damaged over time.

What causes code P223F?

The most common causes are: bank 2 sensor ceramic aged and high-resistance; weak heater supply or high resistance in the heater wiring; sensor overheated by misfire or very high exhaust temperature.

Related codes

• P223EO2 Sensor Reference Resistance Out Of Range (Bank 1)
• P223DO2 Sensor Pumping Current Range/Performance (Bank 2)
• P0050HO2S Heater Control Circuit (Bank 2 Sensor 1)
• P0155O2 Sensor Heater Circuit Bank 2 Sensor 1

Sources

• gsi.ext.gm.com: 18OBDG03A Engine Diagnostics
• gsi.ext.gm.com: 16OBDG05 Engine Diagnostics
• bosch-motorsport.com: Data Sheet 69034379 Lambda Sensor LSU 4.9
• law.cornell.edu: 13 CCR 1968.2

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.