What it means
The negative current control circuit for the Bank 1 Sensor 3 oxygen sensor is above its expected electrical range.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The negative-current control circuit serves the Bank 1 Sensor 3 oxygen sensor, which monitors exhaust oxygen on the Bank 1 side. The control module sets P2A3D when this circuit’s electrical level rises above its expected range, which can happen with a short to voltage, a failed sensor, or poor connector contact.
Common causes
Most likely first.
- Wiring short to voltage
- Faulty oxygen sensor
- Poor connector contact
Symptoms
- Check-engine light
How to diagnose it
- Save freeze-frame data with a scan tool and note when the Bank 1 Sensor 3 circuit was detected above range.
- Identify Bank 1 Sensor 3 from vehicle service information, then inspect its harness and connector for chafing, heat damage, corrosion, or loose pins.
- Check the circuit for a short to voltage and verify connector contact using the manufacturer’s wiring diagram.
- With the sensor disconnected as specified, test the circuit and compare readings with the manufacturer’s specification to distinguish a harness fault from a sensor fault.
- If wiring and connections are sound, test the Bank 1 Sensor 3 sensor and control circuit to the manufacturer’s specification.
Common fixes
- Repair a wire shorted to voltage or damaged near the exhaust.
- Restore secure, clean contact at the Bank 1 Sensor 3 connector.
- Replace the Bank 1 Sensor 3 oxygen sensor if it fails the specified tests.
Can I keep driving?
The check-engine light may be the only sign, though emissions monitoring can be affected. If the engine behaves normally, limit driving to necessary trips while arranging diagnosis; stop if the light flashes or the engine begins running poorly.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.