P0153: O2 Sensor Circuit Slow Response Bank 2 Sensor 1

What does P0153 mean?

The oxygen sensor before the catalytic converter on bank 2 (sensor 1) is the main control sensor for the mixture. It is either a switching sensor (about 0.1 V lean to 0.9 V rich) or a wide-band sensor that works with a pump current evaluated by an interface chip. Bank 2 exists only on engines with two exhaust manifolds. P0153 is the bank 2 counterpart of P0133: the sensor reacts too slowly to mixture changes. GM measures passively the average response time in both directions across 300/400–600 mV over 60 s and also fails too few transitions; Ford modulates the mixture itself and evaluates amplitude, signal line length or response times. The test runs once per drive at warm part load, two trips. The previous obdex title of this code wrongly repeated P0152's 'High Voltage'.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on (after two drive cycles)
• Slightly higher consumption
• Higher emissions, possible emissions test failure
• P0430 may follow

Common causes

• High Aged, sooted or poisoned upstream sensor (oil, silicone, coolant, additives)
• Medium Exhaust leak ahead of the sensor (manifold gasket, crack)
• Medium Sensor heater weak or intermittent (sensor too cold)
• Medium Mixture fault: air leak, injectors, fuel pressure, air flow sensor
• Low Wiring resistance or aftermarket sensor with different characteristics

Likelihood is a general estimate across vehicles; your make and model may differ.