Engine Speed Does Not Return to Idle

Engine Speed Does Not Return To Idle

SYMPTOM: When a shift-down is performed, the engine speed does not smoothly return to the idling speed.

DIAGNOSTIC PROCEDURE
1. CHECK A/T FLUID LEVEL
Check the A/T fluid level again.

OK or NG
OK >> GO TO 2.
NG >> Refill ATF.

2. CHECK SELF-DIAGNOSIS RESULTS
Perform self-diagnosis.

Do the self-diagnosis results indicate front brake solenoid valve, direct clutch solenoid valve, ATF pressure switch 1, ATF pressure switch 5, accelerator pedal position sensor, vehicle speed sensor A/T (revolution sensor) and vehicle speed sensor MTR?
YES >> Check the malfunctioning system. Refer to "DTC P1757 FRONT BRAKE SOLENOID VALVE", "DTC P1762 DIRECT CLUTCH SOLENOID VALVE", "DTC P1841 ATF PRESSURE SWITCH 1", "DTC P1845 ATF PRESSURE SWITCH 5", "DTC P0720 VEHICLE SPEED SENSOR A/T (REVOLUTION SENSOR)", "DTC P1721 VEHICLE SPEED SENSOR MTR".
P Code Charts

"DTC P2122, P2123 APP SENSOR" (for VQ35DE) or "DTC P2122, P2123 APP SENSOR" (for VK45DE), "DTC P2127 / P2128 APP SENSOR" (for VQ35DE) or "DTC P2127. P2128 APP SENSOR" (for VK45DE), "DTC P2138 APP SENSOR" (for VQ35DE) or "DTC P2138 APP SENSOR" (for VK45DE).
P Code Charts

NO >> GO TO 3.

3. CHECK SYMPTOM
Check again.

OK or NG
OK >> INSPECTION END
NG >> GO TO 4.

4. CHECK TCM
Perform TCM input/output signal inspection.

OK or NG
OK >> INSPECTION END
NG >> GO TO 5.

5. DETECT MALFUNCTIONING ITEM
Check the following items:
^ Power supply and ground circuit for TCM.
^ A/T assembly harness connector pin terminals for damage or loose connection with harness connector.

OK or NG
OK >> Replace the transmission assembly.
NG >> Repair or replace damaged parts.