What does P1150 mean on a Ford?

P1150. Lack of Upstream HO2S Switch - Adaptive Fuel at Limit (Bank 2). Applies to F-150, Mustang, Expedition, Explorer with V6 and V8 engines.

What causes P1150 on a Ford?

Fuel trims maxed out by a bank 2 lean or rich fault Slow bank 2 upstream oxygen sensor Bank 2 vacuum leak or injector fault Exhaust leak ahead of the bank 2 sensor Sensor contamination

How do I fix P1150 on a Ford?

Read bank 2 long-term trims to find the correction direction Repair the underlying fuel or air fault first Inspect the bank 2 exhaust for leaks Check sensor switching speed Replace the bank 2 upstream sensor after trims normalize

Code

P1150

Lack of Upstream HO2S Switch - Adaptive Fuel at Limit (Bank 2)

Category: Powertrain - Fuel/Air Metering
Severity: Check Engine Light
Applies to: F-150, Mustang, Expedition, Explorer with V6 and V8 engines
Related: P0174 System Too Lean (Bank 2) on OBD Codes List

Findings, check these first

Fuel trims maxed out by a bank 2 lean or rich fault
Slow bank 2 upstream oxygen sensor
Bank 2 vacuum leak or injector fault
Exhaust leak ahead of the bank 2 sensor
Sensor contamination

Standard procedure

Read bank 2 long-term trims to find the correction direction
Repair the underlying fuel or air fault first
Inspect the bank 2 exhaust for leaks
Check sensor switching speed
Replace the bank 2 upstream sensor after trims normalize

Code lookup

Type a code above, or start from a symptom or a common code.

Press / to jump to the box. Ford-enhanced powertrain, body, chassis and network codes. Generic P0xxx codes live on OBD Codes List.

Sources and review

Review: checked against the recorded source material.

OBDII.pro: P1150 Ford definition
live reference page (obdii.pro)
Supports: Ford-family meaning for P1150: Lack Of HO2S21 Switch - Adaptive Fuel At Limit
Fetched directly. obdii.pro is a publisher independent of the engine-codes family.
P1150 FORD Code: Meaning, Causes, and Symptoms | OBD2 Codes
live reference page (obd2-codes.co)
Supports: Ford meaning for P1150: Lack of Upstream Heated Oxygen Sensor Switch Adaptive Fuel Limit Bank 2
Fetched directly. obd2-codes.co phrasing matches the engine-codes family, so it counts as one publisher.

Last updated 2026-09-04.

Report a correction for P1150. Include your vehicle, the issue and a source if you have one.

This fault is part of the Ford fuel and ignition codes guide. It covers the family and the order to check it.