What it means
The ECM detects a high fault on the 14 volt power module current sensor b 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
Current Sensor B monitors current in the 14-volt power module, and the engine control module uses its signal to assess low-voltage system operation. This code sets when the Sensor B circuit signal rises above the expected electrical range, which may indicate a short to battery positive, an open sensor circuit, or poor terminal contact.
Common causes
Most likely first.
- Signal wire shorted to B+
- Open sensor
- Connector pins corroded - high contact resistance
Symptoms
- Check-engine or hybrid-system warning light on
- Charging-system warning light may come on
- Charging or 12-volt system performance may be affected
How to diagnose it
- Use a compatible scan tool to save freeze-frame data and check whether the Sensor B signal is unusually high, fixed, or missing.
- Check for related charging-system codes and note any 12-volt warning symptoms present when the fault set.
- With the vehicle switched off, inspect the Sensor B connector and wiring for an unplugged connection, corrosion, damaged insulation, or an open wire.
- Using the wiring diagram and manufacturer's procedure, test the Sensor B circuit for an open and a short to battery positive.
- If the circuit and connector pass, test Current Sensor B and replace it if the specified checks confirm it is open or faulty.
Common fixes
- Reconnect and secure a loose Sensor B connector.
- Repair an open or damaged wire in the Sensor B circuit.
- Repair a Sensor B signal wire shorted to battery positive.
- Replace Current Sensor B if testing confirms it is faulty.
Can I keep driving?
The engine control module may not manage the 12-volt system reliably with a high Sensor B signal. Avoid unnecessary driving if a charging warning is present, and stop safely if electrical functions weaken or the vehicle reports a power-system fault.
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.