P2224: NOx Sensor Heater Sense Circuit High (Bank 2)

P2224 is logged when the heater sense signal of the bank 2 NOx sensor is too high, which the electronics sees as a short to supply voltage or as an interrupted heater reading near infinite resistance. The bank 2 code appears in no public manufacturer document. GM documents the bank 1 version P2211 for the 3.0L LZ0 as an HTemp pin shorted toward supply: 80 failed of 160 samples, powertrain relay above 11 V, sensor bus relay switched on, Type B over two trips. Since the sensor module cannot judge cell temperature, it holds back its NOx value and SCR control for that bank falls back on modelled emissions. P2223 is the low direction, P2220 a high fault on the control side, P2225 a sporadic sense fault.

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

Symptoms

• Malfunction indicator lamp on after two trips
• Bank 2 NOx sensor stays unready

Most likely causes

• Heater element in the bank 2 probe open, read as maximum resistance
• Sense lead shorted to a voltage source
• Fault in the sensor module input stage

What to check, in order

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

1. Read the codes and the NOx data before and after the SCR catalyst
2. Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
3. Check the sensor's connector and wiring
4. Look for exhaust leaks ahead of the sensor
5. Confirm that the AdBlue/DEF is of good quality
6. Replace the sensor only after ruling out power, ground, and leaks

Good to know

• Repair difficulty: medium
• It affects emissions.

What each character of P2224 means

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

Frequently asked questions

Can I keep driving with code P2224?

You can usually keep driving in the short term, but get it repaired soon: on many diesels, the warning eventually limits starting or engine power.

What causes code P2224?

The most common causes are: heater element in the bank 2 probe open, read as maximum resistance; sense lead shorted to a voltage source; fault in the sensor module input stage.

Related codes

• P2211NOx Sensor Heater Sense Circuit High (Bank 1 Sensor 1)
• P2221NOx Sensor Heater Sense Circuit (Bank 2)
• P2223NOx Sensor Heater Sense Circuit Low (Bank 2)
• P2225NOx Sensor Heater Sense Circuit Intermittent (Bank 2)
• P2220NOx Sensor Heater Control Circuit High (Bank 2)

Sources

• law.cornell.edu: 13 CCR 1968.2
• gsi.ext.gm.com: 25OBDG04A

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.