What it means
The voltage sense circuit B for the generator reports a circuit b high condition. Generator output regulation may be impaired.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Generator voltage sense circuit B supplies the control module with a signal used to regulate generator output. P2CC4 sets when the module reads that signal higher than expected, which can happen if the wire is shorted to power or the circuit connector is faulty.
Common causes
Most likely first.
- Voltage sense wire shorted to power
- Faulty voltage sense circuit or connector
Symptoms
- Check-engine light
- Battery or charging system warning light
- Dim or flickering lights
- Difficulty starting or a discharged battery
How to diagnose it
- Review freeze-frame data and compare live circuit B readings with battery voltage to establish when the signal goes high.
- Inspect the circuit B harness for damaged insulation or contact with a powered wire.
- Check generator and module connectors for corrosion, loose terminals, or a pin bridging adjacent contacts.
- Test circuit B for a short to power and verify continuity using the wiring diagram and the manufacturer’s procedure.
- Measure circuit B voltage at the generator and module to locate where the reading becomes high.
- If the circuit passes, test the generator sense output and module input before replacing components.
Common fixes
- Repair circuit B wiring shorted to a power feed.
- Clean or replace damaged connector terminals that cause a high reading.
- Repair chafed insulation or incorrect wire contact in the harness.
- Replace a faulty sense-circuit component if testing confirms it.
- Repair the generator or module only after circuit tests isolate the fault.
Can I keep driving?
If the charging warning is on, lights flicker, or the battery is not holding charge, limit driving because incorrect generator regulation can discharge the battery or affect vehicle electronics. Reduce electrical loads and stop safely if electrical systems become unreliable.
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.