CorollaFix

P1790 (blink 65) on Toyota Corolla E120: ST SOLENOID VALVE MALFUNCTION

Short answer: P1790 means “ST SOLENOID VALVE MALFUNCTION”. The car’s computer has found a fault in the ECT U340E system and turns on the Malfunction indicator lamp (Check Engine). First check: workshop check order (RM821E): INSPECT TRANSMISSION WIRE(ST) -> CHECK WIRE HARNESS AND CONNECTOR(Transmission wire − ECU) -> INSPECT TRANSMISSION 3WAY SOLENOID ASSY NO.3(ST).

Code
P1790 · blink 65
System
ECT U340E
Dashboard light
Malfunction indicator lamp (Check Engine)
Applies to
4-speed A/T U340E. PK: ZZE122R-GEPNKP 1.8 auto from 07.2005 (EPC fig 3501/3512 note (0507- )ATM..PKN); JDM NZE121 1NZ autos
Confidence
high (official Toyota RM821E)
Source
toyotamanuals.gitlab.io

Symptoms and when it is set

  1. ECU memorizes DTC P1790/65 if (a) or (b) condition below is detected once or more, but ECU does not start O/D OFF indi- cator light blinking. (a) Solenoid resistance is 30 W or lower (short circuit) when solenoid energized. (b) Solenoid resistance is 100 kW or higher (open circuit) when solenoid is not energized.

Likely causes

  1. Transmisstion wire; Wire harness; ST solenoid valve; Engine ECU

What to check, in order

  1. Workshop check order (RM821E): INSPECT TRANSMISSION WIRE(ST) -> CHECK WIRE HARNESS AND CONNECTOR(Transmission wire − ECU) -> INSPECT TRANSMISSION 3WAY SOLENOID ASSY NO.3(ST)

Related on this car

← P1780/97 P0500/42 →

Clearing the code does not fix the fault. If it comes back, the problem is still there. For brakes, airbags and steering, see a trained mechanic.