P22BE: O2 Sensor Reference Voltage Circuit High (Bank 2 Sensor 2)

P22BE is stored when the reference voltage lead of the bank 2 downstream wide-band probe carries more voltage than a working Nernst cell can produce. A healthy cell produces well under one volt from a source of roughly 300 ohms, so contact with the heater feed, a 5 V line or battery voltage swamps it, and a cracked ceramic can let heater potential leak into the cell. No maker documents this code publicly. On upstream probes the top of the scale is already an open-circuit criterion: Ford and Saab react above 4.7 V, VW's Touareg above 4.80 V, while Ford files shorts to battery under P0152 for bank 2. Under CARB rules a secondary sensor must also be checked for readings outside its range. P22BB is the open, P22BD the low reading, P22B1 bank 1. The lamp comes on.

Bank 2 is the side without cylinder 1, so it only exists on V or boxer engines. Sensor 2 is the sensor after the catalytic converter.

Symptoms

• Check engine light
• Bank 2 downstream oxygen reading pinned at the upper limit
• Heater codes for the same sensor may appear alongside

Most likely causes

• Nernst-cell lead shorted to the heater supply or another live wire
• Cracked ceramic letting heater voltage into the sensing cell
• Faulty sensor interface in the engine control module

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. Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
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 P22BE means

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

Frequently asked questions

Can I keep driving with code P22BE?

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 P22BE?

The most common causes are: nernst-cell lead shorted to the heater supply or another live wire; cracked ceramic letting heater voltage into the sensing cell; faulty sensor interface in the engine control module.

Related codes

• P22BBO2 Sensor Reference Voltage Circuit/Open (Bank 2 Sensor 2)
• P22BCO2 Sensor Reference Voltage Performance (Bank 2 Sensor 2)
• P22BDO2 Sensor Reference Voltage Circuit Low (Bank 2 Sensor 2)
• P22B1O2 Sensor Reference Voltage Circuit High (Bank 1 Sensor 2)
• P2250O2 Sensor Reference Voltage Circuit High (Bank 2 Sensor 1)

Sources

• law.cornell.edu: 13 CCR 1968.2
• bosch-motorsport.com: Data Sheet 69034379 Lambda Sensor LSU 4.9
• newtonnet.co.uk: fordobd2012
• saabwisonline.com: dtc p2237 p2239 p2243 p2251 or p2626

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.