P0781
1-2 Shift Malfunction
The TCM detects a fault during the 1-to-2 upshift. The actual gear ratio after the shift command does not match the expected ratio for second gear.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Common causes
Ordered by how often each turns out to be the cause.
- Shift solenoid A faultyCommon
- 1-2 clutch slippingPossible
Parts involved
- Shift Solenoid A
- Transmission Clutch Pack
- Valve Body
P0781 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.