What it means
The input current sensor of battery charger B reports a circuit high condition. Charging current measurement is unreliable.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Battery charger B uses an input current sensor to tell the control module how much current is entering that charger. The module sets P2D84 when the sensor signal is higher than the circuit's expected range, making the measured charging current unreliable.
Common causes
Most likely first.
- Signal wire shorted to B+
- Current sensor offset drifted high
- Connector pins corroded - high contact resistance
Symptoms
- Charge status indicator shows fault
- Charging may not start or interrupts
- Slower-than-expected charge rate
How to diagnose it
- Record freeze-frame data and compare charger B's reported input current with charging status to see when the high reading occurs.
- With the vehicle safely powered down, inspect charger B's sensor connector and harness for corrosion, damaged insulation, loose pins, or a signal wire touching B+.
- Check the connector terminals and wiring for corrosion or poor contact that could affect the sensor signal.
- Measure the sensor signal and its reference and ground circuits using the manufacturer's procedure, looking for an unexpectedly high signal or a short to B+.
- If the wiring and connections are sound, compare the sensor's readings with an independent current measurement under the specified conditions to check for high offset drift.
Common fixes
- Clean and secure corroded or loose sensor connector terminals.
- Repair a damaged signal wire or short to B+ in charger B's harness.
- Restore a faulty sensor reference or ground connection.
- Replace charger B's input current sensor if its signal remains high with sound wiring.
Can I keep driving?
Avoid relying on normal charging until the fault is diagnosed; charging may fail to start or stop unexpectedly. Follow the vehicle's charging-system warnings, and stop charging if the system reports a fault or behaves abnormally.
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.