p1151
Moderate
Ford · Trucks
Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean (Bank 2)
Quick Answer
Error code P1151 on your Ford Trucks means: Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean (Bank 2). This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
  1. Vacuum leak on bank 2 side of the engine
  2. Faulty upstream heated oxygen sensor (HO2S) on bank 2
  3. Low fuel pressure affecting bank 2 fuel delivery
  4. Exhaust leak upstream of the O2 sensor on bank 2
  5. Clogged fuel injectors on bank 2 cylinders
How to Fix It
1
Monitor upstream O2 sensor bank 2 voltage with a scan tool at idle
2
Check for vacuum leaks using a smoke test on bank 2
3
Test fuel pressure and volume at the fuel rail
4
Inspect exhaust manifold for leaks on bank 2 side
5
Replace upstream O2 sensor on bank 2 if it fails testing
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 2)
Vacuum hoses
Fuel filter
Exhaust manifold gasket
Related Error Codes
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