Engine Speed Does Not Return to Idle (Light Braking D4-D3)

15. Engine Speed Does Not Return To Idle (Light Braking D4 -> D3)

SYMPTOM:
- Engine speed does not smoothly return to idle when A/T shifts from D4 to D3.
- Vehicle does not decelerate by engine brake when turning overdrive control switch OFF.
- Vehicle does not decelerate by engine brake when shifting A/T from "D" to "2" position.

1. CHECK SELF-DIAGNOSTIC RESULTS





Does self-diagnosis show damage to overrun clutch solenoid valve circuit after cruise test?
Yes or No
Yes >> Check overrun clutch solenoid valve circuit.
No >>GO TO 2.

2. CHECK THROTTLE POSITION SENSOR





Check throttle position sensor.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace throttle position sensor.

3. CHECK A/T FLUID CONDITION





1. Remove oil pan.
2. Check A/T fluid condition.
OK or NG
OK >>GO TO 4.
NG >> GO TO 6.

4. DETECT MALFUNCTIONING ITEM
1. Remove control valve assembly.
2. Check the following items:
- Overrun clutch control valve
- Overrun clutch reducing valve
- Overrun clutch solenoid valve
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.

5. CHECK SYMPTOM
Check again.
OK or NG
OK >> INSPECTION END
NG >>
1. Perform TCM input/output signal inspection.
2. If NG, recheck TCM pin terminals for damage or loose connection with harness connector.

6. DETECT MALFUNCTIONING ITEM
1. Remove control valve assembly.
2. Check the following items:
- Overrun clutch control valve
- Overrun clutch reducing valve
- Overrun clutch solenoid valve
3. Disassemble A/T.
4. Check the following items:
- Overrun clutch assembly
- Oil pump assembly
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.