Heated Oxygen Sensor Insufficient Switching Bank 1 Sensor 2 (Ford)
What does P1137 mean?
The P1137 code means the vehicle's onboard diagnostic system has detected: Heated Oxygen Sensor Insufficient Switching Bank 1 Sensor 2 (Ford). This is a moderate severity code.
Common Symptoms
- Check Engine Light on
- Decreased fuel economy
- Failed emissions test
- Slight sulfur smell from exhaust
- No noticeable drivability issues in some cases
Probable Causes (Ranked by Likelihood)
- Faulty downstream oxygen sensor (Bank 1 Sensor 2) Very High
- Exhaust leak before the downstream sensor High
- Deteriorated catalytic converter Moderate
- Wiring damage to the downstream O2 sensor Moderate
- Engine running rich due to other faults Low
Step-by-Step Diagnostic Procedure
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Monitor Bank 1 Sensor 2 O2 sensor data with a scan tool during driving
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Check for exhaust leaks between the catalytic converter and sensor
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Compare upstream and downstream O2 sensor readings to assess catalytic converter health
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Inspect the O2 sensor wiring and connector for damage or corrosion
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Replace the downstream O2 sensor if it shows slow or insufficient switching
Frequently Asked Questions
What does insufficient switching mean?
The downstream O2 sensor should show a relatively steady voltage if the catalytic converter is working properly. Insufficient switching means the sensor is not responding normally, which could indicate a lazy sensor or a converter issue.
Can I pass emissions with P1137?
No. P1137 will typically cause an emissions test failure because the sensor monitors catalytic converter efficiency. The code must be resolved and the Check Engine Light cleared before testing.
Should I replace the catalytic converter for P1137?
Not necessarily. Start by replacing the downstream O2 sensor, as it is the most common cause and much less expensive. Only replace the catalytic converter if diagnostics confirm it is not functioning properly.