P0750 – Shift solenoid valve S1 malfunction

System: AT
Dashboard light: Check engine light (MIL)
Check-engine blink code: —
Applies to: 1SZ-FE (by platform)
Description: Shift solenoid valve S1 malfunction
Possible causes: Trouble area: 1.Shift solenoid valve S1 stuck or open/short circuit 2.Valve body
What to check: Checking points: 1.Check solenoid wiring and resistance 2.Check ATF level and condition
Confidence: medium (Toyota Echo 1999–2002 factory diagnostics, same XP10 platform; not confirmed on JDM 1SZ-FE)

From the factory service material. Clear the code and test-drive to confirm it returns. Search all fault codes · Common problems · Warning lights