Heated Oxygen Sensor Heater Circuit Malfunction Bank 1 Sensor 3 (Ford)
What does P1146 mean?
The P1146 code means the vehicle's onboard diagnostic system has detected: Heated Oxygen Sensor Heater Circuit Malfunction Bank 1 Sensor 3 (Ford). This is a low severity code.
Common Symptoms
- Check Engine Light on
- Failed emissions test
- No noticeable drivability symptoms
- Slightly increased emissions during warm-up
- Possible minor fuel economy decrease
Probable Causes (Ranked by Likelihood)
- Failed heater element in Sensor 3 Very High
- Damaged wiring to third O2 sensor High
- Blown heater fuse or relay Moderate
- Corroded sensor connector Moderate
- PCM heater driver issue Low
Step-by-Step Diagnostic Procedure
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Locate Bank 1 Sensor 3 (farthest downstream on Bank 1 exhaust)
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Measure heater resistance at the sensor connector
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Check the heater fuse and relay
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Inspect wiring for damage along the exhaust route
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Replace the sensor if the heater element has failed
Frequently Asked Questions
What is Sensor 3 on a Ford?
Sensor 3 is a third oxygen sensor found on some Ford vehicles with dual catalytic converters in series. It is located after the second catalytic converter and monitors overall exhaust system efficiency.
Do all Ford vehicles have a Sensor 3?
No. Sensor 3 is typically found on larger Ford vehicles with V8 engines that have extended exhaust systems with multiple catalytic converters, such as the F-150, Expedition, and E-Series vans.
Is P1146 expensive to fix?
The repair is moderately priced. The sensor itself costs $50 to $150, and labor varies depending on accessibility. On some vehicles, Sensor 3 is hard to reach, which increases labor time.