Lack of Upstream HO2S Switch - Sensor Indicates Rich (Bank 2)
Findings, check these first
- Leaking bank 2 injector
- High fuel pressure
- Bank 2 upstream sensor stuck rich
- Restricted bank 2 air path
- Purge valve stuck open
Standard procedure
- Test fuel pressure and injector leak-down on bank 2
- Check bank 2 plugs for fouling
- Test the purge valve seal
- Verify intake and filter condition
- Replace the bank 2 upstream sensor after excluding real rich causes
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: P1152 Ford definition
live reference page (obdii.pro)
Supports: Ford-family meaning for P1152: Lack Of HO2S21 Switch - Sensor Indicates Rich
Fetched directly. obdii.pro is a publisher independent of the engine-codes family.
- P1152 FORD Code: Meaning, Causes, and Symptoms | OBD2 Codes
live reference page (obd2-codes.co)
Supports: Ford meaning for P1152: Lack of Upstream Heated Oxygen Sensor Switch Sensor Indicates Rich 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 P1152. 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.
Related Fuel/Air Metering codes
- P1131Lack of Upstream HO2S Switch - Sensor Indicates Lean (Bank 1)
- P1151Lack of Upstream HO2S Switch - Sensor Indicates Lean (Bank 2)
- P1233Fuel Pump Driver Module Off-Line
- P1289Cylinder Head Temperature Sensor Signal Greater Than Self-Test Range
- P1299Cylinder Head Over-Temperature Protection Active
- P1100Mass Air Flow Sensor Intermittent