P0050 — HO2S Heater Control Circuit (Bank 2, Sensor 1) | OBD-II Code

What Does This Error Mean?

Code P0050 means your vehicle's computer detected a problem with the heater circuit inside the oxygen sensor on Bank 2, Sensor 1. This is the upstream oxygen sensor on the side of the engine that does NOT contain cylinder 1. The heater helps the sensor reach operating temperature quickly so fuel delivery stays accurate.

Affected Models

Most vehicles with V6 or V8 engines (2000–present)
Ford F-150
Chevrolet Silverado
Toyota 4Runner
Nissan Pathfinder

Common Causes

The oxygen sensor itself has failed — the internal heater element burned out
A blown fuse in the circuit that powers the sensor heater
Damaged or corroded wiring between the sensor and the engine control module (ECM)
A faulty relay that controls power to the sensor heater
The engine control module (ECM) has failed and is not sending power to the heater

How to Fix It

Use an OBD-II scanner to confirm P0050 is stored. Note any other codes present at the same time.

Additional codes like P0053 or P0054 can help narrow down whether this is a wiring or sensor issue.
Locate the fuse box and check the fuse for the oxygen sensor heater circuit. Replace any blown fuse.

Check your owner's manual or the fuse box lid for the correct fuse location.
Inspect the wiring harness and connector going to the Bank 2, Sensor 1 oxygen sensor. Look for melted, frayed, or corroded wires.

Heat from the exhaust manifold often damages nearby wiring over time.
Test the oxygen sensor heater resistance with a multimeter. A healthy sensor heater reads between 2–30 ohms. A reading of 'OL' (open loop) means the heater has failed.

This test requires disconnecting the sensor from the wiring harness first.
Replace the Bank 2, Sensor 1 oxygen sensor if it fails the resistance test. Clear the code and drive 50–100 miles to allow the system to run a full readiness test.

Use an OEM or quality aftermarket sensor. Cheap sensors often fail quickly.

When to Call a Professional

If replacing the oxygen sensor and checking the fuse does not clear P0050, have a mechanic test the wiring harness with a multimeter. ECM faults causing this code are rare but possible. Expect $150–$350 for an oxygen sensor replacement at a shop.

Frequently Asked Questions

Is it safe to drive with code P0050?

You can drive short distances, but you should fix it soon. A faulty oxygen sensor heater causes the engine to run on estimated fuel trims until the sensor warms up naturally. This leads to slightly worse fuel economy and higher emissions. Long-term driving can damage the catalytic converter.

Will P0050 cause my car to fail an emissions test?

Yes, in most states it will. P0050 sets a readiness monitor as incomplete, and most emissions tests require all monitors to be ready. Fix the code and drive a full drive cycle before your test.

How do I know which side is Bank 2 on my engine?

Bank 2 is the side of the engine that does NOT contain cylinder number 1. On most inline engines, there is only one bank. On V6 and V8 engines, check your repair manual or look up your specific engine layout online.