What it means
Voltage on the upshift switch line is above the expected window. 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 upshift switch sends a request for a higher gear, and the transmission controller monitors voltage on its signal line. This code sets when that voltage is above its expected range. An open switch contact, a wire shorted to battery voltage, or a poor connector can cause the controller to miss or misread the request.
Common causes
Most likely first.
- Open switch contacts
- Switch wire shorted to B+
- Connector pins corroded - high contact resistance
Symptoms
- Check engine or transmission warning light may be on
- Upshift switch may not respond or may register unexpectedly
- Manual shift mode may behave unpredictably
How to diagnose it
- Save freeze-frame data and check scan-tool upshift-switch status and related transmission codes.
- With the vehicle safely parked, operate and release the upshift control while checking whether live status follows each action.
- Inspect the switch connector and accessible wiring for open contacts, chafing, a short to battery voltage, corrosion, or loose pins.
- Move the accessible harness gently while watching live switch status to look for a change or dropout.
- Test the upshift switch circuit for an open or short to power according to the manufacturer’s wiring diagram and specification.
Common fixes
- Repair wiring shorted to battery voltage.
- Repair an open or damaged wire in the upshift switch circuit.
- Clean or replace corroded terminals and secure loose connections.
- Replace the upshift switch if its contacts remain open when they should change state.
Can I keep driving?
If normal automatic shifts are predictable, drive gently and avoid depending on manual upshift control until repaired. Stop using the control if it causes unexpected shifts, and avoid driving if the transmission enters limp mode or loses drive.
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.