What it means
Same as P05D0 with the signal shorted to supply. 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
Switch A reports the driver's mode selection on an electrical signal circuit monitored by the vehicle controller. P05D2 sets when the signal is abnormally high, consistent with a short to supply or a fault holding the switch A input high.
Common causes
Most likely first.
- Signal shorted to supply
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Drive-mode selection may be unavailable or unchanged
- A drive-mode warning or check-engine light may illuminate
How to diagnose it
- Use a scan tool to monitor switch A's reported state while operating it and check whether the input remains high.
- Inspect switch A's wiring and connector for pinched insulation, corrosion, moisture, or terminals touching a supply circuit.
- Using the wiring diagram, test the switch A signal for a short to supply and isolate harness sections as specified by service information.
- Wiggle the harness while watching live data to locate an intermittent short to supply.
- If the wiring checks out, test switch A and the controller input circuit against the manufacturer's specification.
Common fixes
- Secure or clean the switch A connector and correct any terminal contact issue.
- Repair pinched or damaged signal wiring that is contacting a supply wire.
- Replace switch A if it produces a high signal when testing confirms the switch is faulty.
- Repair a confirmed fault in the controller input circuit.
Can I keep driving?
You can generally drive if the vehicle behaves normally, but switch A may not select the mode you request. Avoid relying on a particular drive mode until the fault is fixed.
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.