What it means
The ECM detects a intermittent/erratic fault on the battery charger hybrid/ev battery output current sensor circuit. Reading cannot be used reliably for control.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The battery charger’s output-current sensor reports current delivered to the high-voltage battery. The control module monitors whether that signal stays stable during charging and sets P0D55 when it jumps or drops erratically, making the current reading unreliable.
Common causes
Most likely first.
- Sensor connector not seated
- Noisy ground reference
- Connector with intermittent contact under vibration
Symptoms
- EV/hybrid system warning light on
- Reduced power output or limp mode
- Charging may fail or be slowed
- Reduced electric range
How to diagnose it
- Check freeze-frame data and live current readings for sudden changes, and note whether the fault appears during charging or vehicle movement.
- Inspect the output-current sensor connector for incomplete seating, loose terminals, corrosion, or signs of vibration-related movement.
- Inspect the sensor wiring and ground reference for damage, loose connections, or poor contact that could make the signal unstable.
- With the vehicle safely powered down according to its service instructions, check the signal and ground circuits for intermittent continuity using the manufacturer's procedure.
- If the wiring and ground remain stable, test the output-current sensor and charger input against the manufacturer's diagnostic specifications.
Common fixes
- Seat and secure the output-current sensor connector.
- Clean or repair loose, corroded, or damaged terminals and wiring.
- Repair the sensor ground connection if it is unstable.
- Replace the output-current sensor if its signal remains erratic with sound wiring and connections.
Can I keep driving?
If charging starts and stops or power is reduced, limit driving to what is needed to reach a safe place for diagnosis. A fluctuating current signal can cause charging interruptions or reduced-power operation.
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.