NO.6 LOW MAXIMUM SPEED AND POOR ACCELERATION [GF4AX-EL]


6	Low maximum speed and poor acceleration
DESCRIPTION	• Vehicle acceleration is poor at start. • Delayed acceleration when accelerator pedal is depressed while driving.
POSSIBLE CAUSE	• If the clutch is stuck or does not stay in 3GR or 4GR, malfunction is in the engine circuit. 1. Clutch slippage, burnt • Line pressure low • TP sensor malfunction • VSS malfunction • Input/turbine speed sensor malfunction • Sensor GND malfunction • Shift solenoids A, B, or C malfunction • Body GND malfunction • Control valve body malfunction 2. Transaxle fixed in 3GR or 4GR (Operation of fail-safe function) • Short or open circuit in wiring harness • Poor connection of connector • Malfunction of electronic parts of output and input system 3. Insufficient starting torque (Suspected when in-gear condition, shift control and engine circuit are normal) • Torque converter malfunction (Poor operation, stuck) 4. Engagement of TCC operation range (Operation of fail-safe function) • TFT sensor malfunction (Short or open circuit) Note • Before following the troubleshooting steps, make sure that the Automatic Transaxle On-Board Diagnostic and Automatic Transaxle Basic Inspection are conducted.


STEP	INSPECTION		ACTION
1	With ignition switch at the ON position, does the O/D OFF indicator light correspond to the O/D OFF switch operation?	Yes	Go to the next step.
1		No	Go to No.26 "O/D OFF INDICATOR LIGHT DOES NOT ILLUMINATE WHEN O/D OFF SWITCH IS TURNED TO ON", or No.27 "O/D OFF INDICATOR LIGHT ILLUMINATES WHEN O/D OFF SWITCH IS NOT TURNED ON".
2	Go to No.12 "LACK/LOSS OF POWER-ACCELERATION/CRUISE". (See NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISE [L3 R.H.D.].) Engine control system normal?	Yes	Go to the next step.
2		No	Repair or replace any malfunctioning parts according to the inspection results.
3	Connect the WDS or equivalent to DLC-2. Access TFT PIDs. Drive the vehicle while monitoring PIDs. (See PCM INSPECTION [L3 R.H.D.].) Are the PIDs within the specification?	Yes	Go to the next step.
3		No	Inspect the TFT sensor and related wiring harness: intermittent open/short circuit during vibration. Repair if necessary and proceed to Step 7.
4	Access TRD, TRL, TRS, TP, TSS and VSS PIDs. Drive the vehicle in D, 2, and 1 ranges while monitoring PIDs (O/D OFF switch off). (See PCM INSPECTION [L3 R.H.D.].) Are the PIDs within the specification?	Yes	Go to the next step.
4		No	TRD, TRL or TRS PID: • Inspect the TR switch and related harness: intermittent open/short circuit during vibration. Repair if necessary and proceed to Step 7. TP PID: • Inspect if output signal from the TP sensor changes smoothly. Repair if necessary and proceed to Step 7. TSS PID: • Inspect the input/turbine speed sensor and related wiring harness: vibration, intermittent open/short circuit. Repair if necessary and proceed to Step 7. VSS PID: • Inspect for open circuit of the VSS and related wiring harness intermittently. Repair if necessary and proceed to Step 7.
5	Stop the engine and turn the ignition switch to the ON position. Connect the WDS or equivalent to DLC-2. Simulate SSA/SS1, SSB/SS2 and SSC/SS3 PIDs for ON. Is operating sound of the shift solenoids heard?	Yes	Go to the next step.
5		No	Inspect connection of the shift solenoid A, B, or C terminal on the ATX for bent terminal, damage, corrosion or looseness. Inspect for stuck shift solenoid? (See Operating Inspection (On-vehicle Inspection).) If the shift solenoids are normal, inspect for open or short circuit between the PCM terminals 92, 66 or 40 and the pressure control solenoid terminals A, B, or C.
6	Remove the torque converter. Inspect the torque converter. (See ATX Workshop Manual (GF4AX-EL)) Is the torque converter normal?	Yes	Replace the control valve body and repair or replace any malfunctioning parts. (See ATX Workshop Manual (GF4AX-EL)) If any problem remains, replace the transaxle and repair or replace any malfunctioning parts. (See AUTOMATIC TRANSAXLE AND TRANSFER REMOVAL/INSTALLATION [GF4AX-EL].)
6		No	Replace the torque converter.
7	• Verify the test results. - If normal, return to the diagnostic index to service any additional symptoms. - If the malfunction remains, inspect the related Service Information and perform repair or diagnosis. • If the vehicle is repaired, troubleshooting is completed. • If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM.