NO.25 TRANSMISSION OVERHEATS


25	Transmission overheats
DESCRIPTION	• Burnt smell is emitted from transmission. • Smoke is emitted from transmission.
POSSIBLE CAUSE	• The malfunction is restricted to hindrance of coolant at the oil cooler. In addition, overheating of the transmission may be caused by a malfunction of the transmission fluid temperature sensor. • The malfunction is restricted to hindrance of coolant at the cooler. – Oil cooler malfunction – Excessive amount of ATF – Torque converter malfunction – Clutch slippage • In the event of clutch slippage, a DTC (incorrect gear ratio) is output. – TCC piston 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.)


STEP	INSPECTION		ACTION
1	Inspect the oil cooler pipes for bends, damage, corrosion or kinks. Are the oil cooler pipes normal?	Yes	Go to the next step.
1		No	Replace any malfunctioning parts.
2	Perform the stall test. (See Stall Speed Test.) Is the stall speed normal?	Yes	Go to the next step.
2		No	Repair or replace any malfunctioning parts.
3	Inspect the following PCM PIDs using the WDS or equivalent. (See PCM INSPECTION.) • APP1 • APP2 • TP_REL Are the PID values normal?	Yes	Go to the next step.
3		No	Repair or replace any malfunctioning parts.
4	Disconnect the TCM connector. Is the resistance between ground terminal 2M or 2Q at the TCM connector and body ground 5.0 ohms or less?	Yes	Go to the next step.
4		No	Repair the wiring harness. Reconnect the TCM.
5	Inspect the pressure control solenoid circuit. (See SOLENOID VALVE INSPECTION.) Is it normal?	Yes	Go to the next step.
5		No	Repair or replace any malfunctioning parts.
6	Remove the torque converter. Inspect the torque converter. (See AUTOMATIC TRANSMISSION REMOVAL/INSTALLATION.) (See AT Workshop Manual.) Is the torque converter normal?	Yes	Overhaul the control valve body and repair or replace any malfunctioning parts. (See AT Workshop Manual.) If the problem remains, overhaul the transmission and repair or replace any malfunctioning parts. (See AT Workshop Manual.)
6		No	Replace the torque converter. (See AUTOMATIC TRANSMISSION REMOVAL/INSTALLATION.)
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 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. (See TCM REMOVAL/INSTALLATION.)