P0137 fault code: what it means

P0137: Bank 1 downstream O2 sensor voltage stays low.

Engine and gearbox (powertrain) · Minor

Usual causes, most likely first

failed rear O2 sensor
exhaust leak between cat and rear sensor
damaged wiring or connector

P0137 by make

Audi

Rear oxygen sensor (after the cat) voltage low. Usually the sensor, not the cat.

Usual causes: worn rear oxygen sensor; sensor wiring or plug fault; exhaust leak near the sensor; poor earth

Skoda

Rear oxygen sensor (after the cat) voltage low. Usually the sensor, not the cat.

Usual causes: worn rear oxygen sensor; sensor wiring or plug fault; exhaust leak near the sensor; poor earth

Volkswagen

Rear oxygen sensor (after the cat) voltage low. Usually the sensor, not the cat.

Usual causes: worn rear oxygen sensor; sensor wiring or plug fault; exhaust leak near the sensor; poor earth

What the repair usually costs

Air-fuel ratio / front O2 sensor replace (upstream)NZ$270–NZ$750 · A$260–A$730
O2 sensor replace (downstream / after cat)NZ$180–NZ$480 · A$180–A$460

Not sure what P0137 means on your car? Ask Credov.

Before you clear it

Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.

Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.