Error Code P1150 is defined as Air/Fuel Ratio Sensor Circuit Range/Performance Malfunction Bank 2 Sensor 1.

This error code is a generic trouble code, meaning it applies to all vehicles equipped with OBD-II system or vehicles made since 1996 up to present. Specifications on the definition, troubleshooting, and repairs of course, vary from one make and/or model to another.


The A/F sensor or Air-Fuel ratio sensor changes its output voltages depending on the air-fuel ratio. Based on the output voltage, the PC< (powertrain control module, also known as ECM or engine control module in other vehicle makes) determines whether the air-fuel ratio is rich or lean, and then adjusts the stoichiometric air-fuel ratio. The PCM also checks the fuel injection volume compensation value to check whether the A/F sensor value is deteriorating or not. This deterioration is determined by both the output voltage variation and fuel and fuel trim variation.

Error Code P1150 is detected when the A/F sensor output voltage change its value outside of the PCM’s expected value.

Common Symptoms

The most common symptom for this error code is the activation of the check engine light on the dashboard.

Possible Causes

There are many factors that attribute to this error code, such as:

  • Faulty Air fuel Ratio (A/F) Bank 2 Sensor 1
  • Open or shorted air fuel Ratio (A/F) Bank 2 Sensor 1 harness
  • Poor electrical connection Air fuel Ratio (A/F) Bank 2 Sensor 1 circuit
  • Fault in the fuel pressure
  • Fault in the fuel injector
  • Air leaks in the intake

How to Check

Technicians start their diagnosis for this error code by removing the air filter box assembly to access the transmission range switch.

Then, they turn the key to the On position without starting the vehicle. Next, they move the shifter to neutral position; align the alignment holes between the shift lever and the switch.

Next, they insert a 5mm drill bit into the adjustment hole to verify for proper alignment for the neutral position.

Other component that must be checked includes:

  • Ignition Coil A Primary/Secondary Circuit Malfunction
  • Fuel Temperature Sensor B Circuit Range/Performance
  • Cylinder 4 Contribution/Balance Fault

How to Fix

Depending on its diagnosis, there are many ways to fix this error code. Some of the most common repairs are:

  • Repair or replacement of A/F Bank 2 Sensor 1
  • Repair or replacement of faulty electrical connections at A/F Bank 2 Sensor 1 circuit
  • Repair or replacement of open or shorted A/F Bank 2 Sensor 1 harness
  • Repair or replacement fuel pressure or fuel injector
  • Repairing air leaks in the intake

Though seemingly simple, this error code can come alongside other error codes, which makes it a little tricky to address. It is very important to take your vehicle to your dealer or to a professional technician to have this issue addressed and fixed as soon as possible.