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2008 - MX-5 - Transmission/Transaxle

NO.22 NO ENGINE BRAKING [SJ6A-EL]



22

No engine braking

DESCRIPTION

  • Engine speed drops to idle but the vehicle coasts when the accelerator pedal is released during cruising at medium to high speeds.

  • Engine speed drops to idle but the vehicle coasts when accelerator pedal is released when in M range (1GR) at low vehicle speed.

POSSIBLE CAUSE

  • Clutch slippage, burnt (C4 clutch/B1 brake/B2 brake/B4 brake)

    • Line pressure low

      • VSS malfunction

      • Improper signal from PCM (engine speed, accelerator pedal position, throttle position, engine coolant temperature, engine torque signals)

      • Line pressure control solenoid malfunction

      • Control valve body 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

  • Do the following symptoms occur concurrently?

    • Engine flares up or slips during acceleration

    • Engine flares up or slips when shifting

Yes

Go to No.14 “ENGINE FLARES UP OR SLIPS WHEN UPSHIFTING OR DOWNSHIFTING”, or No.15 “ENGINE FLARES UP OR SLIPS WHEN ACCELERATING VEHICLE”.

No

Go to the next step.

2

  • 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.

3

Yes

Inspect the ATF condition.

No

Replace the control valve body.

(See CONTROL VALVE BODY REMOVAL [SJ6A-EL].)

(See CONTROL VALVE BODY INSTALLATION [SJ6A-EL].)

4

  • 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.




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