Internal fault in the engine control unit's oxygen sensor processing circuit; Poor power supply or earth connection to the control unit, including low or unstable battery voltage; Short, chafed wiring or corroded connector in the bank 2 oxygen sensor circuits affecting the control unit's input; Water ingress or corrosion inside the control unit connector or housing; Outdated or faulty control unit software where the manufacturer has identified it as a cause for this code; Faulty bank 2 oxygen sensor pulling its heater or signal circuit out of range.

P064E

Internal Control Module O2 Sensor Processor Performance Bank 2.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
6: AreaComputer and output circuits
4E: FaultThe specific fault in that area

What it means

P064E means the engine control unit has found a fault in the part of its own circuitry that processes the oxygen sensor signals for bank 2, the side of the engine opposite cylinder 1. The unit's self-checks found that this processor was not working or reporting correctly, so it cannot trust the bank 2 oxygen sensor readings. The exact monitoring strategy varies by manufacturer and engine.

Symptoms

Engine warning light on
Poor or uneven fuel economy
Rough idle or hesitation on some engines
Other oxygen sensor or fuel trim codes stored alongside it
Failed emissions test
Fuelling running in a fixed default mode rather than adjusting to the sensors

Possible causes

Internal fault in the engine control unit's oxygen sensor processing circuitlikely
Poor power supply or earth connection to the control unit, including low or unstable battery voltagepossible
Short, chafed wiring or corroded connector in the bank 2 oxygen sensor circuits affecting the control unit's inputpossible
Water ingress or corrosion inside the control unit connector or housingpossible
Outdated or faulty control unit software where the manufacturer has identified it as a cause for this codepossible
Faulty bank 2 oxygen sensor pulling its heater or signal circuit out of rangerare

How to diagnose

Read all stored and pending codes and freeze frame data, and note whether other oxygen sensor, heater, or power supply codes are present
Check battery condition and charging voltage, as low or unstable voltage can set internal control unit faults
Inspect the bank 2 oxygen sensor wiring and connectors for chafing, heat damage, corrosion, and water
Inspect the control unit connectors and housing for moisture, corrosion, bent or pushed-back pins
Check the control unit's main power feeds and earth connections for voltage drop under load
Check bank 2 oxygen sensor heater and signal circuits for shorts to power, earth, or each other, following the wiring diagram for the model
Look up manufacturer service information for software updates or known issues for this vehicle and engine
Clear the code and road test to see if it returns, then recheck live oxygen sensor data for bank 2

How to fix

Repair or replace damaged wiring and corroded connectors in the bank 2 oxygen sensor circuits
Repair poor power or earth connections to the control unit and correct any battery or charging fault
Dry out and clean affected connectors, and fix the source of any water ingress
Update the control unit software if the manufacturer lists an outdated calibration as a known cause for this code
Replace or repair the control unit, with correct coding, only after wiring, power, and software causes are ruled out
Replace the bank 2 oxygen sensor only if testing shows it is damaging the circuit

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but fuelling control may be degraded, so economy, emissions, and running quality can suffer. Get it diagnosed soon, and avoid long journeys or heavy loads if it runs poorly.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.