What does code P1781 mean?

Q: What does code P1781 mean?

Upshift Delay Switchover Valve ATCC Y35. P1781 on Mercedes-Benz vehicles indicates that the transmission control module has detected an electrical fault in the upshift delay switchover valve circuit, which is part of the automatic transmission control (ATCC) system and identified as component Y35. The valve is responsible for momentarily delaying upshifts to smooth gear changes under certain driving conditions, and the code sets when the control module sees an unexpected voltage or current draw on the valve's circuit.

DTC codes / Mercedes-Benz codes / P1781

P1781 · Mercedes-BenzUpshift Delay Switchover Valve ATCC Y35

P1781 on Mercedes-Benz vehicles indicates that the transmission control module has detected an electrical fault in the upshift delay switchover valve circuit, which is part of the automatic transmission control (ATCC) system and identified as component Y35. The valve is responsible for momentarily delaying upshifts to smooth gear changes under certain driving conditions, and the code sets when the control module sees an unexpected voltage or current draw on the valve's circuit.

SystemPowertrain

Code typeMercedes-Benz specific

SeverityMedium

Fix difficultyIntermediate

AreaTransmission

Guidance is general and written for Mercedes-Benz vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.