P0826: Up and Down Shift Switch Circuit
What to do
Manual mode may ignore you, act on requests you did not make, or both. Automatic shifting is unaffected throughout. Corrosion in a connector is a more likely cause than a failed paddle, so ask for the circuit resistance to be checked rather than the switch simply swapped.
What this code means
A fault in the combined circuit carrying both manual shift requests. Where P0815 and P0816 describe separate upshift and downshift circuits, this code covers the common arrangement in which both share a single wire.
The way that sharing works explains the failure modes. Each switch places a different resistance across the same circuit, so the module reads one voltage for "upshift", another for "downshift", and a third for "neither" — three states on two wires instead of four wires for two switches. It is an elegant saving with one consequence: a resistor that has drifted, or a connection that has developed resistance of its own, moves the measured voltage into a neighbouring band. The module then sees a shift request that was never made, or fails to see one that was.
So phantom manual shifts and unresponsive paddles are the same fault on this kind of circuit, and both point at resistance rather than at a broken wire.
Likely causes
Start here
- Corroded or loose connector · easy
- Faulty manual shift switch · easy
Less common
- Faulty clock spring in steering wheel · moderate
- Open circuit in switch wiring · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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