NO.8 DOES NOT SHIFT TO 4GR[GF4AX-EL]

id0503a3808200

8
Does not shift to 4GR
DESCRIPTION
•  Vehicle does not upshift from 3GR to 4GR even though vehicle speed is increased.
•  Vehicle does not shift to 4GR even though accelerator pedal is released in D range at 60 km/h {37 mph}.
POSSIBLE CAUSE
•  Basically, TCC does not operate when fail‐safe is operating. Verify the DTCs first. If the TCC operates when driving at high speeds only, the malfunction (improper adjustment) is in the O/D OFF switch circuit or TR switch circuit.
Caution
•  If the TCC is stuck, inspect it. In addition, inspect the oil cooler for foreign particles which may have mixed in with the ATF.
1.  TCC piston slippage, burnt
•  Line pressure low
•  APP sensor malfunction
•  ECT sensor malfunction
•  VSS malfunction
•  Input/turbine speed sensor malfunction
•  Sensor GND malfunction
2.  TFT sensor malfunction
•  Short or open circuit in wiring harness
•  Poor connection of connector
•  Sensor malfunction
3.  TR switch malfunction
•  Short or open circuit in wiring harness
•  Poor connection of connector
•  Sensor malfunction
•  Selector lever adjustment incorrect
•  TR switch adjustment incorrect
4.  TCC solenoid valve malfunction
•  Short or open circuit in wiring harness
•  Poor connection of connector
•  Solenoid valve stuck
5.  O/D OFF switch malfunction
6.  Torque converter malfunction
7.  Control valve body malfunction
Note
•  Before following the troubleshooting steps, make sure that the Automatic Transaxle On-Board Diagnostic and Automatic Transaxle Basic Inspection are conducted.

Diagnostic procedure

STEP

INSPECTION

ACTION
1
Turn the ignition switch to the ON position.
Does the O/D OFF indicator light indication correspond to the O/D OFF switch operation?
Yes
Go to the next step.
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 TO ON”.
2
Drive the vehicle in D range and inspect following:
•  1–2 shift up and down
•  2–3 shift up and down
Are all shift-up and shift-down possible?
Yes
Go to the next step.
No
No shift at all:
•  Go to No.7 “NO SHIFTING”.
Abnormal shift:
•  Go to No.9 “ABNORMAL SHIFTING”.
3
Connect the M-MDS to DLC-2.
Access TFT and TFTV PIDs.
Drive the vehicle while monitoring PIDs.
(See PCM INSPECTION[L3].)
Are the PIDs within the specification?
Yes
Go to the next step.
No
Inspect the TFT sensor and related wiring harness: vibration, intermittent open/short circuit.
4
Access TRD, APP1, APP2, TSS and VSS PIDs.
Drive the vehicle in D range while monitoring PIDs (O/D OFF switch off).
(See PCM INSPECTION[L3].)
Are the PIDs within the specification?
Yes
Go to the next step.
No
TRD PID:
•  Inspect the TR switch and related wiring harness: for intermittent open/short circuit during vibration.
APP1, APP2 PID:
•  Inspect that the output signal from the APP sensor changes smoothly.
TSS PID:
•  Inspect the input/turbine speed sensor and related wiring harness: for intermittent open/short circuit during vibration.
VSS PID:
•  Inspect for intermittent open circuit at the VSS and related wiring harness.
5
Stop the engine and turn the ignition switch to the ON position.
Connect the M-MDS 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.
No
Inspect connection of the shift solenoid A, B, or C terminal on the ATX for bent terminals damage, corrosion or looseness.
Inspect for stuck shift solenoid?
(See SOLENOID VALVE INSPECTION[GF4AX-EL].)
If the shift solenoids are normal, inspect for open or short circuit between the PCM terminals 1E, 1F or 1G and the coupler component 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].)
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.