What it means
The voltage in sensor power supply C is above the expected range. This may affect components supplied by that circuit; which ones depends on the vehicle.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Sensor power supply C is a shared power circuit that feeds one or more sensors; the supplied components vary by vehicle. The control module monitors this supply and sets P06E8 when its voltage rises above the expected range, potentially disrupting readings from several components.
Common causes
Most likely first.
- Supply line shorted to higher voltage
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check engine light on
- Possible limp mode or no-start
- Multiple follow-up faults across modules
- Reset/relearn may be needed after repair
How to diagnose it
- Record freeze-frame data and scan all modules for related sensor or supply faults to identify which systems may share supply C.
- Use the vehicle wiring information to identify the components on supply C, then inspect their connectors and harness for corrosion, water, pin damage, or chafing.
- Check whether any supply C wire is pinched against a battery-positive or other higher-voltage source, especially near recent repairs.
- With the fault present, measure supply C at the relevant connector and compare it with the manufacturer's specification.
- If the reading is high, isolate branches as directed by the wiring information and test for a short to a higher-voltage circuit; repair the affected wiring or connector.
- If wiring and connections check out, verify the module's supply and ground before considering a control-module fault.
Common fixes
- Repair chafed or pinched supply C wiring that is contacting a higher-voltage source.
- Clean or repair corroded, loose, or damaged connector terminals.
- Repair a short between supply C and a battery-positive or other higher-voltage circuit.
- Correct a faulty module power or ground connection if testing identifies one.
- Replace a confirmed faulty control module and perform any required reset or relearn.
Can I keep driving?
Drive only if the vehicle runs and responds normally; avoid unnecessary trips because affected sensors can cause poor operation, limp mode, or a no-start. Multiple warning lights or abnormal engine behaviour warrant stopping somewhere safe and arranging diagnosis.
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.