Lack of O2 Switches - Bank 1 Sensor 2 Lean
Findings, check these first
- Exhaust leak ahead of the bank 1 downstream sensor
- Aging downstream sensor stuck lean
- Gutted or failed catalytic converter
- Upstream lean condition carrying through
- Sensor heater fault keeping it inactive
Standard procedure
- Smoke test the exhaust ahead of the rear sensor
- Verify the sensor heater works
- Check converter integrity
- Fix upstream fuel control faults first
- Replace the downstream sensor after excluding leaks
Code lookup
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Sources and review
Review: checked against the recorded source material.
- OBDII.pro: P1137 Ford definition
live reference page (obdii.pro)
Supports: Ford-family meaning for P1137: Lack Of HO2S Switch - Sensor Indicates Lean
Fetched directly. obdii.pro is a publisher independent of the engine-codes family.
- P1137 FORD Code: Meaning, Causes, and Symptoms | OBD2 Codes
live reference page (obd2-codes.co)
Supports: Ford meaning for P1137: Lack Of O2 Switches Bank 1 Sensor 2 Lean
Fetched directly. obd2-codes.co phrasing matches the engine-codes family, so it counts as one publisher.
Last updated 2026-09-05.
Report a correction for P1137. Include your vehicle, the issue and a source if you have one.
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