What it means
Same as P05BC with the signal shorted to ground. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
How it works
The stop-start mode switch sends a signal that tells the control module whether the driver wants to change the system’s mode. P05BE sets when the switch signal is too low, commonly because the signal wire is shorted to ground, so the module may not recognize the selection.
Common causes
Most likely first.
- Signal shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check-engine light
- Stop-start mode may not respond to the switch
- Stop-start may remain enabled or unavailable
How to diagnose it
- Use a scan tool to monitor the stop-start switch input and confirm that it remains low while the switch is operated.
- Inspect the switch connector and harness for chafing, damaged insulation, moisture, corrosion, or a pin pushed back in the connector.
- Move the harness gently while watching the live input to see whether the signal changes and help locate an intermittent short to ground.
- With the circuit isolated according to the manufacturer’s procedure, check the signal wire for a short to ground.
- If the wiring is sound, test the switch and control-module input to identify a failed component.
Common fixes
- Repair chafed signal-wire insulation or wiring shorted to ground.
- Clean or repair corroded connector pins and restore proper terminal fit.
- Replace a faulty stop-start mode switch if its output remains low.
- Repair or replace the control module if its input is confirmed faulty.
Can I keep driving?
The fault usually affects stop-start mode selection rather than basic engine operation, but the system may ignore the switch or remain in its default mode. Avoid relying on the switch to disable stop-start until the circuit is repaired.
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.