What it means
The ECM detects a range/performance 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 checks whether its reading is plausible for the system's operating conditions. This code sets when the Sensor B value is out of the expected range or does not respond as expected, even though the circuit may not be simply open or shorted.
Common causes
Most likely first.
- Sensor characteristic drifted
- Sensor mounting displaced
- Sensor element aged beyond calibration window
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
- Save freeze-frame data with a compatible scan tool and note the Sensor B reading and charging conditions when the fault set.
- Compare Sensor B live data with other available low-voltage system readings and check for related charging codes.
- With the vehicle switched off, inspect the Sensor B mounting, connector, and nearby wiring for displacement, looseness, corrosion, or damage.
- Have a technician check Sensor B output and circuit integrity against the manufacturer's diagnostic procedure.
- If the circuit and connections are sound, test the sensor's response across operating conditions and replace it if it is outside specification.
Common fixes
- Correct Sensor B mounting or connector position if it has shifted or loosened.
- Repair damaged wiring or poor connections in the Sensor B circuit.
- Replace Current Sensor B if its output is outside the manufacturer's specification.
- Verify the current reading and charging operation after repair.
Can I keep driving?
The charging system may not control the 12-volt supply correctly while the Sensor B reading is unreliable. Avoid unnecessary trips 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.