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2008 - MX-5 - Transmission/Transaxle

NO.17 EXCESSIVE SHIFT SHOCK FROM N TO D OR N TO R POSITION/RANGE [SJ6A-EL]



17

Excessive shift shock from N to D or N to R position/range

DESCRIPTION

  • Strong shock felt when shifting from N to D or N to R position/range at idle.

POSSIBLE CAUSE

  • Shift shock may worsen when the fail-safe is operating. If no DTC is output, the shift shock may worsen due to poor operation of the control valve body or sticking of the clutch.

    • Clutch burnt (N→D: C1 clutch, N→R: C3 clutch or B4 brake)

      • ATF level low

      • Line pressure low

      • Incorrect throttle position signal

      • Incorrect accelerator pedal position signal

      • Incorrect engine speed signal

      • Incorrect engine coolant temperature signal

      • Incorrect engine torque signal

      • Incorrect turbine sensor signal (N→D)

      • TFT sensor malfunction

      • Sensor GND malfunction

      • Shift solenoid A malfunction

      • Shift solenoid F malfunction

      • Line pressure control solenoid malfunction

      • TCC control solenoid malfunction (N→R)

      • Control valve body malfunction

    • Poor hydraulic operation (Malfunction in range change)

    • Idle speed high

    • Poor tightening torque of engine mount, exhaust mount, suspension, propeller shaft

    • Line pressure high

    • Insufficient battery voltage

    • Harness or connector malfunction

    • AT malfunction

NOTE:

  • Before following the troubleshooting steps, make sure that the Automatic Transmission On-Board Diagnostic and Automatic Transmission Basic Inspection are conducted. (See BASIC INSPECTION [SJ6A-EL].)


Diagnostic procedure

STEP

INSPECTION

ACTION

1

  • Does the shift shock occur only when the engine is cold?

Yes

Go to the next step.

No

Go to Step 3.

2

Yes

Go to the next step.

No

Repair or replace part if necessary.

3

  • Perform the initial learning procedure.

    (See Initial Learning.)

  • Does symptom eliminate?

Yes

Troubleshooting is completed.

No

Go to the next step.

4

Yes

Go to the next step.

No

Repair or replace any malfunctioning parts according to the inspection results.

5

Yes

Go to the next step.

No

Repair or replace any malfunctioning parts according to the inspection results.

6

  • Access the following PCM PIDs using the M-MDS.

    • RPM

    • APP

    • TP

    • ECT

    • ENG_TRQ

  • Are PIDs value normal?

Yes

Go to the next step.

No

Inspect and repair suspected PID related part.

7

  • Stop the engine.

  • Inspect following solenoids.

    (See SOLENOID VALVE INSPECTION [SJ6A-EL].)

    • Line pressure control solenoid

    • Shift solenoid A

    • Shift solenoid F

    • TCC control solenoid

  • Are they normal?

Yes

Inspect the ATF condition.

No

8

  • Verify test results.

    • If normal, return to the diagnostic index to service any additional symptoms.

    • If malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis.

      • If the vehicle is repaired, troubleshooting completed.

      • If the vehicle is not repaired or additional diagnostic information is not available, replace the TCM.


Initial Learning

WARNING:

NOTE:

1. Warm-up

CAUTION:

NOTE:

2. Gear shift control learning
3. Inspect learning results


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