p1131
Moderate
Ford · Trucks
Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean (Bank 1)
Quick Answer
Error code P1131 on your Ford Trucks means: Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean (Bank 1). This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
F150F150HF150LF150RF250SDF350SDF-150 King Ranch 2024F-150 Lariat 2024F-150 Limited 2024F-150 Platinum 2024F-150 Tremor 2024F-150 XL 2024F-150 XLT 2024F-250 King Ranch 2024F-250 Lariat 2024F-250 XL 2024F-250 XLT 2024F-350 Lariat 2024F-350 Platinum 2024F-350 XL 2024Maverick Lariat 2024Maverick XL 2024Maverick XLT 2024Ranger Lariat 2024Ranger Raptor 2024Ranger XL 2024Ranger XLT 2024MVKRGR
Likely Causes
How to Fix It
1
Monitor upstream O2 sensor bank 1 voltage with a scan tool at idle
2
Perform a smoke test to check for vacuum leaks on bank 1
3
Test fuel pressure at the fuel rail under load
4
Inspect exhaust manifold and connections for leaks on bank 1
5
Replace upstream O2 sensor on bank 1 if it is sluggish or reading incorrectly
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Upstream O2 sensor (bank 1)
Vacuum hoses
Fuel filter
Exhaust manifold gasket
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