Lack of HO2S Switch — Sensor Indicates Rich (Bank 2)
2009-2012 Ford Flex 3.5L V6
Description
The upstream heated oxygen sensor on Bank 2 is not switching and indicates a persistent rich condition. The sensor is stuck indicating a rich mixture on Bank 2.
Symptoms
- Check Engine Light
- Rich exhaust smell
- Black exhaust smoke
- Poor fuel economy
- Rough idle
Common Causes
- Leaking fuel injector Bank 2
- High fuel pressure
- Faulty O2 sensor stuck rich
- EVAP purge issue
- Coolant entering combustion chamber Bank 2
Diagnostic Steps
- Monitor O2 sensor Bank 2 on scan tool
- Check fuel pressure
- Inspect spark plugs Bank 2 for fouling
- Check for leaking injectors
Repair Notes
Replace O2 sensor if stuck. Check fuel pressure regulator. Inspect injectors.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P1152 on Other Vehicles
Common Questions
What does code P1152 mean on a 2009-2012 Ford Flex?
P1152 stands for "Lack of HO2S Switch — Sensor Indicates Rich (Bank 2)". The upstream heated oxygen sensor on Bank 2 is not switching and indicates a persistent rich condition. The sensor is stuck indicating a rich mixture on Bank 2.
What are the symptoms of P1152 on a Ford Flex?
Common symptoms of P1152 include: Check Engine Light, Rich exhaust smell, Black exhaust smoke, Poor fuel economy, Rough idle.
What causes P1152 on a 2009-2012 Ford Flex?
Common causes of P1152 include: Leaking fuel injector Bank 2, High fuel pressure, Faulty O2 sensor stuck rich, EVAP purge issue, Coolant entering combustion chamber Bank 2.