P0C6D

What it means

P0C6D is the generic code for an intermittent or erratic signal from generator position sensor circuit B. The generator here is the electric machine in a hybrid or electric drivetrain that acts as a generator, and its position (resolver) sensor tells the control unit the rotor angle and speed. The control unit saw the signal drop out, jump or become implausible from time to time rather than fail completely. Which machine is 'circuit B' and where the sensor sits depends on the make and model.

Symptoms

• Hybrid or powertrain warning light on the dashboard
• Car goes into a limited performance or reduced power mode
• Engine starts or restarts roughly, or fails to start intermittently
• Hybrid system stops charging the high-voltage battery or behaves erratically
• Fault appears and disappears, often with vibration, heat or bumps
• Poor fuel economy as hybrid assist is reduced

Possible causes

• Damaged, chafed or corroded wiring to the generator position sensorlikely
• Loose, dirty or water-affected connector at the generator or control unitlikely
• Faulty generator position (resolver) sensorpossible
• Electrical interference from damaged shielding or poor earth connectionspossible
• Fault inside the inverter or hybrid control unitrare
• Mechanical damage or misalignment of the sensor or rotor in the generatorrare

How to diagnose

1. Read all stored and pending codes and note freeze frame data such as speed, temperature and system state to see when the fault occurs
2. Check for related codes on circuit A, motor position sensors or inverter faults, which point towards a shared wiring or supply problem
3. Visually inspect the generator sensor wiring and connectors for chafing, corrosion, water ingress, bent pins and poor locking
4. Wiggle-test the harness and connector with live data displayed to see whether the position signal or speed reading drops out
5. Check the harness for continuity, short to earth, short to supply and resistance against the manufacturer's specification, with the system safely shut down
6. Measure the sensor coil resistances against the model-specific values
7. Check shielding and earth connections of the sensor circuit
8. Only follow high-voltage procedures if trained and qualified, as the generator and inverter carry dangerous voltage

How to fix

• Repair or replace damaged wiring and restore any shielding or earth connections
• Clean, dry and refit connectors, or replace terminals and connectors that are corroded or loose
• Replace the generator position sensor or generator assembly if testing shows it is faulty
• Replace or repair the inverter or control unit only after the wiring and sensor are proven good, applying any manufacturer software update if it is a known cause
• Clear the code after repair and road test to confirm it does not return

Can I keep driving?

Nearby codes

• P0C6CGenericGenerator Position Sensor Circuit B High
• P0C6EGenericHybrid/EV Battery Temperature Sensor A/B Correlation