P1152moderate severityPowertrain
Lack of HO2S Switch — Sensor Indicates Rich (Bank 2)
on 2004 Ford Freestar 3.9L V6 · FWD
What this code means
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.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1