Can drive — fix at your convenience.
This code means the heater circuit inside the downstream oxygen sensor on Bank 1 (Sensor 2) isn't working as expected. The built-in heater normally warms the sensor quickly so it can start reading exhaust accurately, and a fault here is usually caused by a burned-out heater element, a blown fuse, or wiring and connector problems. The most common fix is replacing the oxygen sensor, since the heater is built into it.
$150 – $400
Varies by vehicle and root cause.
Usually yes, at least short term. The fault is in the sensor's heater, not the engine itself, so the car should run normally. Still, get it looked at within a week or two and expect a failed emissions test until the heater circuit is repaired.
Most repairs fall between $150 and $400. Because the heater is built into the oxygen sensor, the usual fix is a new sensor plus labor. If the real problem is just a blown fuse or a wiring fault, the cost can be lower.
No, it's typically low-severity. Your engine isn't in danger and the car drives normally, but the slow-to-heat sensor affects emissions monitoring and can slightly hurt fuel economy. It's best fixed promptly so emissions readiness completes and the car can pass inspection.
The heater warms the oxygen sensor to operating temperature quickly after a cold start, so it can read exhaust accurately before the engine itself heats it. When that heater circuit fails, the sensor takes too long to work, which is what P0142 flags. Replacing the sensor usually restores fast, reliable readings.