Meaning

The transmission control module has detected a fault in the upshift switch circuit, used on automatic transmissions with manual or sequential shift mode (e.g. Tiptronic). The switch input signal is outside expected parameters.

Common causes

• Faulty or worn upshift switch (permanently open contact)
• Short to battery or short to ground in the switch circuit
• Open circuit in wiring to the upshift switch
• Oxidised or loose connectors at the steering column or transmission
• Internal TCM fault on the input reading channel

Symptoms

• Check engine light on
• Unable to upshift in manual/sequential mode
• Manual shift function does not respond to the upshift command
• Sometimes no driving symptoms in automatic mode

Severity

What to do

1. Check continuity and signal voltage at the upshift switch connector with a multimeter
2. Test the upshift switch directly by pressing it and measuring signal switching
3. Inspect wiring for shorts or open circuits between switch and TCM
4. Replace the upshift switch if outside specification
5. Check TCM input to rule out an internal fault

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