DTC P0743 TCC Enable Solenoid Circuit Electrical. Geo Tracker

For 1990-2009 cars only

Makes 🢒 Geo 🢒 1996 🢒 Tracker - 4WD 🢒 DTC 🢒 DTC P0743 TCC Enable Solenoid Circuit Electrical

Automatic Transmission Controls Schematics

Circuit Description

The Torque Converter Clutch (TCC) Solenoid engages the lock-up clutch. The Transmission Control Module (TCM) outputs system voltage in order to turn ON (energize) or remove voltage in order to turn OFF (to de-energize the TCC solenoid). The TCC solenoid controls the hydraulic pressure to the lock-up valve within the transmission. The TCC solenoid remains OFF in the 1st and 2nd gears. The TCC remains ON in the 3rd and 4th gears when the TCM deems appropriate. The TCC solenoid is never ON during 4L operation or when the engine coolant temperature is below 30°C (80°F).

Conditions for Setting the DTC

•	The voltage detected at TCM connector terminal 12 is 2.0V or lower when the TCM commands the TCC control solenoid ON.

•	The voltage detected at TCM connector terminal 12 is 5.5V or higher when the TCM commands the TCC control solenoid OFF.

•	Two driving cycle detection logic

Action Taken When the DTC Sets

•	DTC P0743 stores.

•	The TCM enters the fail-safe mode.

•	The Malfunction Indicator Lamp (MIL) turns ON.

The torque converter clutch does not engage during fail-safe mode operation.

Diagnostic Aids

Inspect for the following conditions:

•	An open or shorted TCC solenoid

•	Faulty electrical circuits (open or short to ground) between the TCC solenoid and the TCM

•	A faulty TCM

The following conditions may cause an intermittent:

•	A reduced connection

•	Rubbed through wire insulation

•	A broken wire inside the insulation

Inspect the TCM harness connectors for the following conditions:

•	Backed out terminals

•	Improper mating

•	Broken locks

•	Improperly formed or damaged terminals

•	Reduced terminal-to-wire connections

If DTC P0743 cannot duplicate, the information included in the Freeze Frame data may be useful in determining the vehicle operating conditions when the DTC set.

Refer to Wiring Repairs in Wiring Systems when repairing any wiring.

DTC Confirmation Procedure

Turn the ignition switch to the LOCK position.
Connect the scan tool to the Data Link Connector (DLC).
Turn the ignition switch ON.
Use the scan tool in order to clear the following items:

•

DTC P0743

•	Any pending DTCs

Start the engine.
Warm the engine up to normal operating temperature.
Shift the manual selector to DRIVE range.

Remain in DRIVE range for 10 seconds.

Accelerate the vehicle in DRIVE range.

Continue driving for 20 seconds at 80 km/h (50 mph).

Stop the vehicle.
Use the scan tool in order to test for a pending DTC.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

The OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. The scan tool creates an electronic copy of the data taken when the fault occurred. The information then stores in the scan tool for later reference.

This step tests the TCC solenoid internal coil resistance.

This step tests for a short to ground in the GRN/YEL wire.

Refer to the above figure.

This step tests for an open in the GRN/YEL wire.

This step inspects the transmission internal electrical harness for damage.

This step tests for a reduced electrical connection that may have set DTC P0743.

This step tests for a faulty TCM.

Step	Action	Value(s)	Yes	No
1	Was the On-Board Diagnostic (OBD) System Check performed?	--	Go to Step 2	Go to On-Board Diagnostic System Check
2	Turn the ignition switch to the LOCK position. Disconnect the TCM connector. Use J 39200 in order to measure the resistance between ground and the TCM harness connector terminal 12. Is the resistance within the specified range?	11-16.6 ohms at 24°C (75°F)	Go to Step 6	Go to Step 3
3	Disconnect the transmission connector C104. Use J 39200 in order to measure the resistance between ground and the TCM harness connector terminal 12. Is the resistance within the range specified in the Value(s) column?	Infinite	Go to Step 4	Go to Step 9
4	Use J 39200 in order to measure the resistance between the TCM harness connector terminal 12 and connector C104 terminal 8. Is the resistance less than the specified value?	2 ohms	Go to Step 5	Go to Step 10
5	Remove the transmission oil pan. Inspect the terminals and internal harness for damage. Replace the TCC shift solenoid if no damage exists. Is the procedure complete?	--	Go to Step 15	--
6	Turn the ignition switch to the ON position. Use J 39200 in order to measure the voltage between ground and the TCM connector terminal 12. Is the voltage less than the specified value?	2 V	Go to Step 7	Go to Step 11
7	Inspect all of the electrical connections for reduced terminal contact or a reduced connection. Do reduced terminal contact or reduced connections exist?	--	Go to Step 12	Go to Step 8
8	Install a known-good TCM. Perform the DTC Confirmation Procedure. Does DTC P0743 reset?	--	Go to Step 14	Go to Step 13
9	Repair the short to ground in the GRN/YEL wire between the TCM and the TCC solenoid. Is the repair complete?	--	Go to Step 15	--
10	Repair the open or the high resistance in the GRN/YEL wire between the TCM and the TCC solenoid. Is the repair complete?	--	Go to Step 15	--
11	Repair the short to voltage in the GRN/YEL wire between the TCM and the TCC solenoid. Is the repair complete?	--	Go to Step 15	--
12	Repair any terminals or connections that exhibit reduced contact. Is the repair complete?	--	Go to Step 15	--
13	Refer to Diagnostic Aids for a possible intermittent condition. If OK, replace the TCM. Is the procedure complete?	--	Go to Step 15	--
14	Refer to Diagnostic Aids for additional information about DTC P0743. Is the action complete?	--	Go to Step 15	--
15	Turn the ignition switch to the LOCK position. Reconnect all the connector(s). Perform the DTC Confirmation Procedure. Does the scan tool display any DTC(s)?	--	Go to the applicable DTC table	System OK