The check engine light has activated with fault code P0983 (Shift Solenoid 'D' Control Circuit High) on my 2004 Toyota Sienna Limited Edition. The vehicle shifts smoothly and shows no noticeable transmission issues, but I'm seeking guidance on how to properly diagnose and resolve this code. Any insights or troubleshooting steps would be greatly appreciated.
I've tested the resistance of the transmission wire harness and connector from the ECM to solenoid S4 — all readings are within specifications. As a result, I'm planning to replace the ECM and monitor if that resolves the issue.
Before replacing the ECM, it's recommended to test the shift solenoid directly with battery voltage to ensure it functions properly under live power conditions.
cj1 wrote: Thu Nov 12, 2020 6:52 pm Before replacing the ECM, it's recommended to test the shift solenoid directly with battery voltage to ensure it functions properly under live power conditions. This test was already performed during bench testing — both resistance and operational response (clicking sound) were confirmed as normal.
Check out this helpful video for P0983 diagnosis in a 2004 Toyota Sienna: https://youtu.be/t87xc5cOvuE