NO.9 ABNORMAL SHIFTING [SJ6A-EL]


id050307801400

9
Abnormal shifting
DESCRIPTION
•  Shift incorrectly (incorrect shift pattern).
POSSIBLE CAUSE
•  There is a malfunction in the signal circuit which controls shifting (Throttle position signal, turbine sensor, VSS), the control valve is stuck, or the clutch circuit is stuck.
―  Clutch slippage, burnt (C1 clutch, C2 clutch, C3 clutch, B1 brake, B2 brake, B3 brake)
•  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
•  VSS malfunction
•  Turbine sensor malfunction
•  Sensor GND malfunction
•  TFT sensor malfunction
•  Line pressure control solenoid malfunction
•  Body GND malfunction
•  Control valve body malfunction
•  TCM malfunction
―  Wheel speed signal malfunction
•  Tire of a different diameter from the standard tire is installed
•  ABS wheel-speed sensor 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].)
•  If a tire of a different diameter from the standard tire is installed, the TCM determines that the driving mode is the AAS mode, and may change to a different shift timing from the normal timing.

Diagnostic procedure

STEP

INSPECTION

ACTION

1
Verify tire condition.
•  Inspect the tire size and air pressure.
•  Is the tire of specified size and air pressure?
Yes
Go to the next step.
No
Replace with a specified tire size or adjust the air pressure of each specified tire to the specified value.
2
Inspect the vehicle wheel-speed signal.
•  Display the following ABS CM DSC CM PIDs using the M-MDS.
―  WSPD_LF
―  WSPD_LR
―  WSPD_RF
―  WSPD_RR
•  Are the monitoring values displayed uniformly while driving?
Yes
Go to the next step.
No
Perform the following inspections:
ABS wheel-speed sensor installation inspection
―  Is the ABS wheel-speed sensor installation normal?
ABS sensor rotor installation inspection
―  Is the ABS sensor rotor installed twisted?
(may cause output of abnormal wave pattern at high speeds.)
―  Are there missing teeth on the sensor rotor?
If there is any malfunction, repair or replace the malfunctioning location.
3
•  Inspect for continuity between the TCM terminal 1P, 1X and battery negative terminal.
•  Is there continuity?
Yes
Go to the next step.
No
Repair or replace the suspected wiring harness.
4
•  Is the line pressure normal?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
5
•  Access the following PCM and TCM PIDs using the M-MDS:
PCM PIDs:
―  RPM
―  APP
―  TP
―  ECT
TCM PIDs:
―  VSS
―  TSS
•  Are the PIDs value normal?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
6
•  Is the TFT sensor normal?
Yes
Go to the next step.
No
Replace the TFT sensor.
7
•  Inspect the line pressure control solenoid.
•  Is the line pressure control solenoid normal?
Yes
Inspect the TCM terminal for bend, damage, corrosion or poor contact.
No
Inspect the coupler component.
•  If normal, replace the control valve body.
8
•  Verify test results.
―  If normal, return to the diagnostic index to service any additional symptoms.
―  If malfunction remains, inspect the related Service 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. (See TCM REMOVAL/INSTALLATION [SJ6A-EL].)