Checking the Lock-Up Function
Checking the lock-up function
Check the diagnostics number
Checking the software
Note! To carry out fault-tracing, the transmission control module (TCM) must be programmed with specific software.
- Ignition on
- Read off the control module diagnostic number.
Check the read off diagnostic number against the diagnostic numbers given in the center table.
If the diagnostic number is included in the table, the control module must be programmed with the latest software.
See the technical journal for information about the most recent software.
Continue - Connecting the T pipe
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Connecting the T pipe
- Deactivate the function for STC/DSTC by pressing in the button for STC/DSTC for approximately 2 seconds
- Ignition off
- Connect the T-pipe 999 7002 Adapter automatic gearbox 4T65E 999 7002 Adapter Automatic Gearbox 4T65E with oil pressure gauge 999 5114 MANOMETER 10 KP 999 5114 Manometer 10 Kp to the coolant hose from the transmission for the oil cooler
- Raise the car so that the drive wheels are clear of the ground.
Warning! Ensure that the car safely raised. Ensure that there are no objects caught in the front wheels.
- Start the engine
- Gear selector in position P
- Activate the function "Block automatic shifting".
Other information
- To connect the T-pipe to the oil cooler for the transmission. See T-pipe, connection to oil cooler T-Pipe, Connection to Oil Cooler.
Allow the engine to run. Select Continue.
Continue - Checking solenoid SL
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Checking solenoid SL
- Engine running
- Move the gear selector to position D
- Activate the solenoid for gear 2 and then the lock-up function
- Check the pressure change on the oil pressure gauge. A considerable change in pressure should be observed
- Deactivate the lock-up function. Check the pressure change.
Repeat the activation and deactivation of the lock-up function a few times to ensure accurate results.
Hint: Unchanged pressure means that the control system is defective.
Did the pressure change?
Yes - Checking the lock-up function
No - Replacing the transmission control system
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Checking the lock-up function
- Engine running
- Car raised so that the driven wheels hang freely
- Move the gear selector to position D
- Read the transmission input speed, the engine speed (RPM), the status of the lock-up function and the position of the accelerator pedal (AP).
Depress the accelerator pedal (AP) and check the lock-up function by comparing the input speed of the transmission and the engine speed (RPM). The transmission and the engine speed (RPM) must be approximately the same. The lock-up function is not functioning if the difference is greater than 100 rpm.
Is the difference in speed (RPM) greater than 100rpm?
Yes - Replacing automatic transmissions
No - Checking the resistance, solenoid SL
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Checking the resistance, solenoid SL
- Ignition off
- Connect the breakout box to the control module connector (transmission side).
Check solenoid SL by measuring the resistance between terminals #A51 (#A51) and #A53 (#A53).
When the transmission is cold (20 °C), the resistance must be 10-11 ohms. When the transmission is at operating temperature (150 °C), the resistance must not exceed 16 ohms.
Other information
- To connect the breakout box, see Connecting the breakout box, 4T65EV-GT Connecting the Breakout Box
- For information about signals, Signal Description.
Was the resistance OK?
Yes - No Fault Found
No - Checking the wiring
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Checking the wiring
- Ignition off
- Control module disconnected
- Connect the breakout box to the control module connector (transmission side)
- Disconnect the transmission connector
- Adapter951 1505 Adapter 20 pin 951 1505 Adapter 20 Pin and breakout box951 1428 Breakout box 951 1428 Breakout Box connected to the transmission connector (control module side).
Check the wiring between control module terminal #A51 (#A51) and transmission connector terminal #T (#A17). Check for an open-circuit. Check for a short-circuit to ground. Check for a short-circuit to supply voltage.
Check the wiring between control module terminal #A53 (#A53) and transmission connector terminal #E (#A5). Check for an open-circuit. Check for a short-circuit to ground. Check for a short-circuit to supply voltage.
Remedy as necessary.
Other information:
- To connect the breakout box, see Connecting the breakout box, 4T65EV-GT Connecting the Breakout Box
- To connect the breakout box to the transmission connector, see Connecting the breakout box, GM automatic transmissions, 4T65EV-GT Connecting the Breakout Box, GM Automatic Transmissions
- For information about signals, see
- Checking wiring and terminals Checking Wiring And Terminals
Was a fault detected?
Yes - Verification
No - Checking the wiring and component
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Checking the wiring and component
- Ignition off
- Open the transmission control system
- Connect adapter951 1505 Adapter 20 pin 951 1505 Adapter 20 Pin and breakout box951 1428 Breakout box 951 1428 Breakout Box to the transmission connector (transmission side).
Check the cable between transmission connector terminal #T (#A17) and solenoid SL terminal #A. Check the cable between transmission connector terminal #E (#A5) and solenoid SL terminal #B. Check these cables for an open-circuit.
Hint: Check solenoid SL by measuring the resistance between solenoid SL terminals #A and #B. When the transmission is cold (approximately 20 °C), the resistance must be 10-11 ohms.
Remedy as necessary.
Other information:
- To open the transmission control system, see Side cover transmission, replacing Side Cover Transmission, Replacing
- To connect the breakout box to the transmission connector, see Connecting the breakout box, GM automatic transmissions, 4T65EV-GT Connecting the Breakout Box, GM Automatic Transmissions
- To replace solenoid SL, see Solenoid lock-up function, replacing Solenoid Lock-Up Function, Replacing
- To replace the cable harness, see Wiring harness / oil temperature sensor, replacing
- For information about signals, Connecting the Breakout Box
- Checking wiring and terminals Checking Wiring And Terminals
Continue - Verification
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Replacing the transmission control system
Replacing the transmission control system
Replacing the control system
The fault was probably caused by an internal fault in the transmission control system. Replace the control system.
Other information
- To replace the transmission control system, see Control system / valve housing, replacing Service and Repair.
Continue - Verification
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Replacing automatic transmissions
Replacing a faulty transmission
- In the event of an internal fault in the transmission, replace the transmission. See Gearbox, removing Gearbox, Removing and Gearbox, installing Gearbox, Installing.
Continue - Resetting the adaptation and oil quality counter
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Resetting the adaptation and oil quality counter
Resetting the adaptation
Resetting adaptation and the counter for "Transmission oil change"
Hint: The transmission has torque controlled adaptive pressure control. Pressure control means that the transmission regulates the pressure itself during each gear shift. This avoids harsh gear shifting. Each gear shift is evaluated by the control module and stored in the memory. This allows for compensation for wear and tear in the transmission and clutch. It is important that the adaptation in the memory is reset after the transmission has been repaired. This is to ensure normal operation. The oil is replaced during repair; the "Transmission oil change" counter must be reset. If the counter is not reset when the fluid is drained and replaced, there is a risk that a diagnostic trouble code (DTC) will be stored in incorrect circumstances.
Note! This applies only if the transmission or one of the components in the transmission have been replaced.
- Ignition on.
Click on the VCT2000 symbol to reset the adaptation and counter.
Continue - Verification
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Resetting the "Transmission fluid" counter
Resetting Transmission fluid change counter
Hint: The transmission control module (TCM) has a counter for the oil quality. The counter counts up if the transmission is exposed to too high a load or an ambient temperature that is too high. If the counter is not reset when the oil is drained or changed, there is a risk that a diagnostic trouble code (DTC) will be stored in faulty circumstances. Therefore it is important that the "Transmission oil change" counter is reset.
Note! This applies only when the transmission fluid is changed and when the fluid is changed when repairs are carried out to the transmission temperature sensor.
- Ignition on.
Reset the counter by clicking on the VCT 2000 symbol.
Continue - Verification
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Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off
- Reconnect the connectors, components, etc.
- Ignition on
Test drive the vehicle following: Test drive schedule, description Test Drive Schedule, Description
During the test drive, oil temperature should be over 20 °C.
Note any deviations in transmission function.
Does the transmission function flawlessly?
Yes - Verification complete
No - VERIFICATION FAILED
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