Code result
P0143
O2 Sensor Circuit Low Voltage
Moderate severity
What it means
The ECU detects a general electrical fault on the third oxygen sensor in the bank 1 exhaust path (typically located after a second catalyst on diesel or large engines with multi-cat exhausts).
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Sensor aged or failed
highOne of the most commonly reported causes for this code — check this first.
Sensor wiring open or shorted
mediumA plausible cause — test and verify before replacing parts.
Related help
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