Signal Too Low. Permanent Fault
Signal too low. Permanent fault
Checking solenoid STH
- Ignition off
- Disconnect the automatic transmission and control module connectors
- Check the control module and automatic transmission connectors for contact resistance and oxidation. Remedy if necessary
- Reconnect the control module and automatic transmission connectors
- Start the car
- Gear selector in position P
- Read off the current through the solenoid circuit
- Depress the accelerator pedal (AP) slowly.
The current should decrease as the accelerator pedal (AP) is depressed. The cause of the fault was contact resistance or oxidation if the current reduces as the accelerator pedal (AP) is depressed.
Other information
- To disconnect the control module, see Transmission control module (TCM), replacing, B5254T2, AW50/51 AWD, B5254T2, AW55-50/51SN Service and Repair
- For information about signals, Signal Specification.
- Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault
Does the current reduce when the accelerator pedal (AP) is depressed?
Yes - Check the quality of the transmission oil
No - Checking solenoid STH
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Check the quality of the transmission oil
Check the quality of the transmission oil
Check the quality of the transmission oil
Note! The transmission fluid quality is extremely important for transmission function. Therefore it is imperative that this is correct.
- Ignition off.
Check the transmission oil quality. Take a sample using the dip stick.
- Replace the transmission fluid if it smells burnt
- Replace the fluid and filter if the transmission fluid contains particles
- Check if there is oil or an oil film in the expansion tank. Oil in the expansion tank indicates leakage from the transmission oil cooler which is positioned in the cooler unit.
Note! The transmission oil is red and must not be confused with black engine oil.
- If the transmission fluid is cloudy or pink, it is contaminated with coolant. In such cases the transmission must be replaced. For checking coolant in transmission oil, see: Checking for coolant in the oil, AW55-50/51SN, AW50/51 AWD, 4T65EV-GT Checking For Coolant In the Oil
When replacing the transmission, the cooler unit, including the additional cooler must be replaced if installed. Replace the hoses between the cooler and the transmission.
Other information:
- To replace the transmission fluid and filter, see Gearbox fluid, replacing Removal and Replacement.
Select an option:
1. The fluid contains water
2. The fluid smells burnt or contains particles
3. No fault detected.
1 - WATER
2 - BURNT
3 - NO-FAULT
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WATER - Replacing the transmission
BURNT - Resetting the oil quality counter
NO-FAULT - Checking the oil level in the transmission
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Checking the oil level in the transmission
Checking the oil level in the transmission
Check the transmission oil level
Note! The transmission fluid level is extremely important for transmission function. Therefore it is imperative that it is correct. In addition the oil level is dependent on oil temperature.
- Start the car
- Read off the oil temperature.
When checking the transmission fluid level, the temperature must be 80-90°C.
At the correct temperature, the oil level should be between "Min hot" and "Max hot".
Oil level
- Too high:Drain the transmission fluid to the correct level
- Too low:Check the transmission for leakage.
Remedy as necessary.
Other information:
- To check and adjust the oil level, see Oil level, checking Checking Oil Level.
Was the transmission fluid level correct?
Yes - OK
No - NOT OK
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OK - Checking solenoid STH
NOT OK - Resetting the oil quality counter
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Checking solenoid STH
- Ignition off
- Disconnect the transmission connector
- Connect adapter 951 1505 Adapter 20 pin 951 1505 Adapter 20 Pin and breakout box 981 3190 Replaced by 9511428 981 3190 Replaced by 951 1428 to the transmission connector (transmission side)
- Connect an ohmmeter between terminals #C (#A3) and #D (#A4) on the breakout box.
The solenoid STH resistance must be between 3 and 5 ohms at 20°C.
Other information:
- 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, Signal Specification.
Was the resistance OK?
Yes - Checking the cables in the circuit for solenoid STH
No - Checking the wiring and component
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Checking the cables in the circuit for solenoid STH
- Ignition off
- Connect the breakout box to the transmission
- Disconnect the control module.
- Disconnect the transmission connector
- Connect adapter 951 1505 Adapter 20 pin 951 1505 Adapter 20 Pin and breakout box 981 3190 Replaced by 9511428 981 3190 Replaced by 951 1428 to the transmission connector (control module side).
Check the cable between control module terminal #A52 and transmission connector terminal #C (#A3) for a short-circuit to ground.
Check the cable between control module terminal #A70 (#B10) and transmission connector terminal #D (#A4) for a short-circuit to ground.
Other information:
- To connect the breakout box to the control module, 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, Signal Specification.
- Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault
Was the wiring OK?
Yes - Checking the wiring and component
No - Erasing diagnostic trouble code (DTC)
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Checking the wiring and component
- Ignition off
- Open the transmission control system.
Check the cable between transmission terminal #C (#A3) and solenoid STH terminal #A. Check the cable between transmission terminal #D (#A4) and solenoid STH terminal #B. Check these cables for a short-circuit to ground.
Hint: Check solenoid STH. Measure the solenoid STH resistance between terminals A and B. The resistance should be between 3-5 ohms.
Replace the cable harness if no fault is found in the solenoid or the terminals.
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 STH, see Solenoid line pressure, replacing
- To replace the cable harness, see Wiring harness / oil temperature sensor, replacing Removal and Replacement
- For information about signals, Signal Specification.
- Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault
Continue - Resetting the adaptation and oil quality counter
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Replacing the transmission
Fault-tracing indicates a mechanical fault in the transmission. Replace the transmission according to Gearbox, removing Gearbox, Removing.
Select "Continue" when the fault has been remedied.
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 oil quality counter
Resetting Transmission fluid change 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
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off.
- Reconnect the connectors, reinstall components etc.
- Raise the car so that the drive wheels are unimpeded.
- Start the car.
- Read off the current through the solenoid circuit.
- Lock the wheels with the brakes. Shift the gear selector to position D.
- Depress the accelerator pedal (AP) slowly.
The current should decrease as the accelerator pedal (AP) is depressed.
Does the current decrease?
Yes - Verification completed
No - Fault-tracing information
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Erasing diagnostic trouble code (DTC)
- Ignition on
- Erase diagnostic trouble codes (DTCs)
- Test drive the car. See Test Drive Form, description Test Drive Schedule, Description.
Continue - Reading off diagnostic trouble codes (DTC)
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Reading off diagnostic trouble codes (DTC)
- Ignition on
- Read off diagnostic trouble codes (DTCs).
Does diagnostic trouble code (DTC) TCM-0010 recur?
Yes - Fault-tracing information
No - FAULT FOUND
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Fault-tracing information
Information
Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.
Do you want to exit fault-tracing?
Yes - Exit Fault-Tracing
No - Attempt New Test
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Attempt New Test - Checking solenoid STH
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