P0137 on a Ford: Causes, Fixes & Repair Cost
🟠 Moderate severity · drivable
Safe to drive, but the check engine light stays on and the car may fail an emissions test until the sensor issue is fixed.
What P0137 means on a Ford
On a Ford, P0137 means the bank 1 downstream oxygen sensor is reporting low voltage. The sensor sits after the catalytic converter and mainly checks converter efficiency, so low voltage usually points to the sensor, its wiring, or an exhaust leak rather than a fuel problem.
Is P0137 common on Fords?
P0137 shows up on higher-mileage Fords like the F-150, Escape, and Explorer, where downstream sensors age and exhaust joints can leak. On Fords, a worn sensor is the usual cause, but wiring near the exhaust can also chafe over time. It is a routine sensor or exhaust repair.
Commonly reported on: F-150, Escape, Explorer, Focus.
Symptoms
- Check engine light is on
- No obvious driveability change in most cases
- Possible failed emissions test
- Occasional slight drop in fuel economy
Common causes
- most common: Worn or failing downstream oxygen sensor
- common: Exhaust leak ahead of the sensor
- common: Damaged or chafed wiring or connector
- less common: Defective aftermarket sensor
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Replace the downstream oxygen sensor | Yes | $80–200 |
| Repair the exhaust leak | Mechanic | $100–300 |
| Repair the wiring or connector | Mechanic | $80–200 |
Frequently asked questions
Other common Ford codes
P0137 on other brands
Looking for the full (non-brand-specific) guide? See the P0137 code page →
Browse all Ford codes: Ford hub →
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.