Heated Oxygen Sensor Heater Circuit Malfunction Bank 2 Sensor 2 (Ford)
What does P1140 mean?
The P1140 code means the vehicle's onboard diagnostic system has detected: Heated Oxygen Sensor Heater Circuit Malfunction Bank 2 Sensor 2 (Ford). This is a low severity code.
Common Symptoms
- Check Engine Light on
- Failed emissions test
- Extended cold-start emissions
- Minimal drivability impact
- Possible slight fuel economy decrease
Probable Causes (Ranked by Likelihood)
- Failed O2 sensor heater element (Bank 2 Sensor 2) Very High
- Blown O2 sensor heater fuse or relay High
- Open or short in heater circuit wiring Moderate
- Water intrusion in O2 sensor connector Moderate
- PCM heater driver fault Low
Step-by-Step Diagnostic Procedure
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Check the O2 sensor heater fuse and relay
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Measure heater resistance at the Bank 2 Sensor 2 connector (typically 2-30 ohms)
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Verify power and ground at the heater circuit connector
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Inspect wiring for heat damage, especially near exhaust components
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Replace the O2 sensor if heater resistance is out of specification
Frequently Asked Questions
Is P1140 the same as P0161?
They are closely related. P0161 is the generic OBD-II code for Bank 2 Sensor 2 heater circuit malfunction, while P1140 is Ford's manufacturer-specific code for the same issue. The diagnosis and repair are identical.
Do I need to replace both downstream sensors?
Not necessarily, but if one downstream sensor heater has failed on a high-mileage vehicle, the other is likely near the end of its life. Replacing both at the same time saves labor costs.
Where is Bank 2 Sensor 2 located?
Bank 2 Sensor 2 is located after (downstream of) the catalytic converter on the Bank 2 side of the engine. On most Ford V8 trucks, this is on the driver side of the exhaust system.