Signal Too High. Permanent Fault
Signal too high. Permanent fault
Checking line pressure solenoid STH
- Raise the car so that the drive wheels are unimpeded.
- Start car.
- Read off current in solenoid circuit.
- Apply the brakes and shift the gear selector to position D.
- Depress accelerator pedal (AP) slowly.
The current should decrease as the accelerator pedal (AP) is depressed.
Does current reduce when the accelerator pedal (AP) is depressed?
Yes - FAULT FOUND
No - Checking wiring and components
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Checking wiring and components
- Ignition off.
Check the cable between control module #A52 and transmission connector (control module side) #24 for a short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check the cable between control module #A70 (#B10) and transmission connector (control module side) #25 for a short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Hint: With the ignition on, the control module connected and the transmission connector disconnected, the voltage between transmission connector #24 and ground should be battery voltage. The voltage between transmission connector #25 and ground should be 0 V.
Remedy as necessary.
Other information
- To connect the breakout box, see Connecting breakout box, Transmission control module (TCM) Connecting Breakout Box, Transmission Control Module (TCM).
- To disconnect transmission connector, see Inspecting/cable harness to solenoids .
- To check/replace line pressure solenoid STH, see Inspecting / replacing solenoids .
- For information about signals, see Signal specification, Transmission control module (TCM) Signal Description AW50-42.
Continue - Checking the control module
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Checking the control module
Hint: The transmission control module (TCM) can malfunction if there has been a short-circuit to supply voltage in the solenoid STH circuit. Check the transmission control module (TCM) as follows:
- Ignition off.
- Reinstall connectors, components etc.
- Raise the car so that the drive wheels are unimpeded.
- Start car.
- Read off current in solenoid circuit.
- Apply the brakes and shift the gear selector to position D.
- Depress accelerator pedal (AP) slowly.
The current should decrease as the accelerator pedal (AP) is depressed.
Does the current decrease?
Yes - Resetting adaptation and oil quality counter
No - Replacing control module and programming
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Replacing control module and programming
Caution! A new control module is delivered without software. The control module must be programmed in order to function after replacement.
For further information about programming and replacing the control module, see Replacing the gearbox control module (TCM) .
Continue - Resetting adaptation and oil quality counter
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Resetting 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 - DONE
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DONE - Verification
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Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Gear selector in position P.
- Start the car.
- 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.
Does the current reduce when the accelerator pedal (AP) is depressed?
Yes - VERIFIED
No - VERIFICATION FAILED
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VERIFICATION FAILED - Fault-tracing information
VERIFIED - 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 line pressure solenoid STH
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