O2 Sensor Circuit Range/Performance (Bank 2 Sensor 1)

What it means

This code appears on engines with two banks. The engine computer found that the upstream sensor reading on the bank without cylinder 1 does not match the operating conditions or what it expects, so mixture control on that bank becomes inaccurate.

Related codes: P2A00P0150P0153P0174P0175

Symptoms4

• Check engine light on.
• Higher fuel consumption.
• Slightly rough idle or hesitation on acceleration.
• Failed emissions test.

Possible causes5

• Aged or contaminated Bank 2 upstream sensor.
• Exhaust leak ahead of the sensor on the Bank 2 side.
• Poor sensor wiring or connector, or a heater circuit fault.
• A real mixture problem on Bank 2 from an air leak or a weak or leaking injector on that bank.
• Engine computer fault (rare).

How to diagnose5

1. Read all stored codes and fix mixture codes such as P0174 or P0175 first.
2. Locate Bank 2 and its upstream sensor in the service information.
3. Compare the sensor signal and fuel trims between banks; a large difference helps locate the problem.
4. Check the Bank 2 side of the exhaust for leaks ahead of the sensor.
5. Inspect the sensor wiring, connector and heater operation.

How to fix5

1. Repair any exhaust leak ahead of the sensor.
2. Repair damaged wiring or the connector.
3. Fix the cause of a real mixture problem on Bank 2.
4. Replace the Bank 2 upstream sensor with a unit that meets the vehicle specification.
5. Clear the codes and confirm fuel trims are stable and the code does not return.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost is low for an exhaust leak or wiring repair and rises when the sensor is replaced; labor may be higher if the sensor is hard to reach.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions