P1646
HO2 Sensor Control Malfunction Bank 1 Upstream
Severity
⚠️ MediumCan you drive?
Yes, but get it checked soon
Approx. repair cost
$28–67 (est.)
Symptoms
- Check Engine light comes on
- Increased fuel consumption
- Unstable engine operation
- Reduced engine power
- Dips during acceleration
Causes
- Faulty oxygen sensor (upper, bank 1)
- Open or short circuit in the sensor circuit
- Poor connection or corroded contacts
- Engine control unit malfunction
- Sensor circuit grounding problems
How to Fix
- Check the condition of the oxygen sensor and its connector
- Check the integrity of the wiring to the sensor
- Check the resistance and voltage at the sensor
- If necessary, replace the oxygen sensor
- Clear error memory and check if error is returned