NO.9 ABNORMAL SHIFTING [FN4A-EL]


BME050301030213

9

Abnormal shifting

DESCRIPTION

• Shift incorrectly (incorrect shift pattern).

POSSIBLE CAUSE

• There is a malfunction in the signal circuit which controls shifting (TP sensor, input/turbine speed sensor, vehicle speed sensor), the control valve is stuck, the accumulator (forward or servo apply) is stuck, or the clutch circuit is stuck.
1. Clutch slippage, burnt
• Line pressure low
• Control valve body malfunction
• Shift solenoid D malfunction
• Shift solenoid E malfunction
• Shift solenoid A malfunction
• Shift solenoid B malfunction
• Shift solenoid C malfunction
• Body GND malfunction
• Accelerator cable mis-adjustment
2. Signal malfunction
• Vehicle speed sensor malfunction
• Sensor GND malfunction
• TP sensor malfunction or mis-adjustment
• Input/turbine speed sensor malfunction
3. TR switch malfunction
• Selector lever adjustment incorrect
• TR sensor adjustment incorrect
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
Disconnect the PCM connector.
Is the resistance between the ground terminal at the PCM connector and the body ground less than 5.0 ohms?
Yes
Go to the next step.
No
Repair open ground circuit. Reconnect the PCM.
2
Inspect the value at the following PCM PIDs using the WDS or equivalent. (See PCM INSPECTION [L3].)
• TP
• TSS
• VSS
Are the PID values normal?
Yes
Overhaul the control valve body and repair or replace any malfunctioning parts. (See ATX workshop manual (FN4A-EL).)
If any problem remains, overhaul the transaxle and repair or replace any malfunctioning parts. (See ATX workshop manual (FN4A-EL).)
No
Repair or replace any malfunctioning parts.