P22AD: O2 Sensor Positive Current Control Circuit High (Bank 1 Sensor 2)

P22AD is the high-side fault on the positive current control line of the bank 1 downstream wide-band probe: the pump-current wire is pulled above its expected level, for example by contact with the heater feed or another supply wire. On Saab's 2010 9-5 the pump-current pins measure roughly 2.8 V at the plug, which gives a feel for the normal bias. GM lists the code in bulletin 21-NA-149 for the 3.0 Duramax LM2, again tied to engine harness chafing, but publishes no limit. Ford sends shorts to power on its upstream wide-band probes to P0132 instead of a dedicated code. The upstream analog is P2239 (Type B at Saab); P22AB is the open circuit, P22AC the low reading, P22BA the bank 2 version. The lamp is lit; driving normally feels unchanged.

Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank. Sensor 2 is the sensor after the catalytic converter.

Symptoms

• Check engine light
• Downstream oxygen reading implausibly high or fixed
• Readiness monitors for catalyst or aftertreatment not completed

Most likely causes

• Pump-current wire shorted to the heater supply or another positive feed
• Internal short between heater and pump cell in the sensor
• Faulty sensor interface in the ECM or sensor 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 P22AD means

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

Frequently asked questions

Can I keep driving with code P22AD?

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 P22AD?

The most common causes are: pump-current wire shorted to the heater supply or another positive feed; internal short between heater and pump cell in the sensor; faulty sensor interface in the ECM or sensor module.

Related codes

• P22ABO2 Sensor Positive Current Control Circuit/Open (Bank 1 Sensor 2)
• P22ACO2 Sensor Positive Current Control Circuit Low (Bank 1 Sensor 2)
• P22BAO2 Sensor Positive Current Control Circuit High (Bank 2 Sensor 2)
• P2239O2 Sensor Positive Current Control Circuit High (Bank 1 Sensor 1)
• P22B4O2 Sensor Negative Current Control Circuit High (Bank 1 Sensor 2)

Sources

• static.nhtsa.gov: MC 10224856 0001
• saabwisonline.com: dtc p2237 p2239 p2243 p2251 or p2626
• newtonnet.co.uk: fordobd2012
• 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.