Signal Too High

Signal too high

Checking the transmission input speed sensor signal








- Ignition off
- Start the engine
- Read off the transmission input speed.
Depress the accelerator pedal (AP) and check that engine speed (RPM) is updated. Compare with the engine speed (RPM).

Other information
- To access the transmission connector, see Connecting the breakout box, GM automatic transmissions, 4T65EV-GT Connecting the Breakout Box, GM Automatic Transmissions
- To access the control module connector, see Connecting the breakout box, 4T65EV-GT Connecting the Breakout Box.





Is the speed updated?

Yes - Intermittent fault

No - Checking wiring and sensors

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Checking wiring and sensors












- Ignition off
- Connect the breakout box to the transmission
- Disconnect the control module
- Disconnect the transmission connector
- Connect adapter951 1505 Adapter 20 pin 951 1505 Adapter 20 Pin and breakout box981 3190 Replaced by 9511428 981 3190 Replaced by 951 1428 to the transmission connector (control module side).
Check the wiring between control module terminals #59 (#A59) and #41 (#A41) and transmission connector terminals #S (#A16) and #V (#A19). Check for a short-circuit to each other.
Check the power supply cable between control module terminal #59 (#A59) and transmission connector terminal #S (#A16). Check for a short-circuit to supply voltage.
Check the signal cable between control module terminal #41 (#A41) and transmission connector terminal #V (#A19). 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 disconnect the transmission control module (TCM), see Transmission control module (TCM), replacing, B5254T2, AW50/51 AWD, B5254T2, AW55-50/51SN Service and Repair
- 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 Signal specification, 4T65EV-GT Signal Specification
- For information about signals to the transmission connector, see Signal description. Connector 4T65 EV/EV-GT, 4T65EV-GT Connector 4T65 EV/EV-GT
- Checking wiring and terminals Checking Wiring And Terminals









Was a fault detected in the cables or terminals?

Yes - Verification

No - Checking the control module

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Checking the control module












- Ignition off
- Transmission control module (TCM) connected
- The breakout box connected
- Transmission connector disconnected
- Connect a temporary cable between terminals #A35 and #A59 on the breakout box
Caution! Check that the temporary cable is connected to the correct terminals. Also check that there is no risk of unintentional short-circuits.

- Ignition on
- Read off the status.
Check that the status is "1" when the temporary cable is connected to the terminals above.
Disconnect the cable end that is connected to terminal #A35 and move the cable to terminal #A53.

Note! Leave the cable end connected to terminal #A59 in place.

Check that the status changes to "0" when the temporary cable has been moved to terminal #A53.
The transmission output speed sensor is defective if the status has changed between "1" and "0" as above and no errors have been detected on the cables or terminals in the preceding checks. Replace the transmission output speed sensor.
The transmission control module (TCM) is defective if the status has not changed between "1" and "0" as above and no errors have been detected on the cables or terminals in the preceding checks. If this is the case replace the control module.
Remedy as necessary.

Other information
- To connect the breakout box, see Connecting the breakout box, 4T65EV-GT Connecting the Breakout Box
- To disconnect the transmission connector, see Connecting the breakout box, GM automatic transmissions, 4T65EV-GT Connecting the Breakout Box, GM Automatic Transmissions
- To check or replace the transmission output speed sensor, see Output speed sensor gearbox, replacing Transmission Output Speed Sensor, Replacing
- To replace the transmission control module (TCM), see Transmission control module (TCM), replacing, B5254T2, AW50/51 AWD, B5254T2, AW55-50/51SN Service and Repair
- For information about signals, see Signal specification, 4T65EV-GT Signal Specification.









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.
Check the cable for power supply between transmission connector terminal #S (#A16) and transmission input speed sensor connector terminal #A. Check for a short-circuit to supply voltage.
Check the signal cable between transmission connector terminal #V (#A19) and transmission input speed sensor connector terminal #B. Check for a short-circuit to supply voltage.
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 the transmission speed sensor, see Input speed sensor transmission, replacing Transmission Input Speed Sensor, Replacing
- To replace the cable harness, see Wiring harness / oil temperature sensor, replacing Removal and Replacement
- For information about signals, see Signal specification, 4T65EV-GT Signal Specification
- Checking wiring and terminals Checking Wiring And Terminals









Continue - Resetting the "Transmission oil change" adaptation and counter

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Resetting the "Transmission oil change" adaptation and 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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Verification




Verification

Hint: After carrying out the repair, check that the fault has been remedied.








- Ignition off.
- Reinstall the connectors, components etc.
- Start the engine and let it idle.
- Read off the transmission speed.
Depress the accelerator pedal (AP) and check that engine speed (RPM) is updated. Compare with the engine speed (RPM).





Is the speed updated?

Yes - Verification completed

No - Fault-tracing information

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Fault-tracing information




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 the transmission input speed sensor signal

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Intermittent fault




- Ignition off.
Check the power supply cable between control module terminal #59 (#A59) and transmission connector terminal #S (#A16). Check for an intermittent short-circuit to supply voltage.
Check the signal cable between control module terminal #41 (#A41) and transmission connector terminal #V (#A19). Check for an intermittent 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 disconnect the control module, see Transmission control module (TCM), replacing, B5254T2, AW50/51 AWD, B5254T2, AW55-50/51SN Service and Repair
- 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 Signal specification, 4T65EV-GT Signal Specification
- Checking wiring and terminals Checking Wiring And Terminals









Continue - Diagnostic trouble code (DTC) information

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Diagnostic trouble code (DTC) information




Information

Fault-tracing information
If the fault is intermittent, do not verify fault-tracing if the fault does not recur.
It is possible to view the information again, or leave fault-tracing for this diagnostic trouble code (DTC).

Do you want to view the information again?

Yes - Attempt New Test

No - Exit fault-tracing

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Attempt New Test - Checking the transmission input speed sensor signal

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