Signal Too Low. Permanent Fault
Signal too low. Permanent fault
Checking lock-up solenoid SL
- Ignition off.
Check the control module and automatic transmission connectors for contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Remedy if necessary
- Ignition on
- Reinstall the components, reconnect the connectors etc.
- Gear selector in position P
- Activate the lock-up solenoid SL.
The value must change between OFF and ON.
Other information:
- To disconnect the control module, see Transmission control module (TCM), replacing, B5254T2, AW50/51 AWD, B5254T2, AW55-50/51SN Service and Repair
- To disconnect 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.
Does the value change?
Yes - FAULT FOUND
No - Checking solenoid SL
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Checking the wiring
- Ignition off
- The transmission connector disconnected.
Check the cable between control module terminal #51 (#A51) and transmission connector (control module side) terminal #T (#A17). Check for a short-circuit to ground. See Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check the cable between control module terminal #A53 and transmission connector (control module side) terminal #E (#A5). Check for a short-circuit to ground. See Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
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 Signal specification, 4T65EV-GT Signal Specification.
Was a fault detected?
Yes - Verification
No - Checking the control module
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Checking solenoid SL
- Ignition off
- Disconnect the automatic 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 (transmission side).
Connect an ohmmeter between terminals E (#A5) and T (#A17).
The solenoid SL resistance must be between 11 and 15 ohms.
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 Signal specification, 4T65EV-GT Signal Specification.
Was the resistance OK?
Yes - Checking the wiring
No - Checking components and wiring
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Checking the control module
- Ignition off
- Transmission connector disconnected
- Connect the control module.
- The breakout box connected
- Ignition on
- Gear selector in position P.
Check the transmission control module (TCM). Measure the voltage between terminal #51 (#A51) and terminal #53 (#A53) on the breakout box. The voltage must be approximately 0 V.
Note! When removing the transmission connector, the control module may store diagnostic trouble codes (DTCs) for the gear-shift position sensor, the shift solenoids and the temperature sensor etc.
Try a new control module if the voltage exceeds 1 V.
Other information:
- To disconnect the transmission connector, see Connecting the breakout box, GM automatic transmissions, 4T65EV-GT Connecting the Breakout Box, GM Automatic Transmissions
- To replace the control module, 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 the voltage above 1V?
Yes - Verification
No - No Fault Found
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Checking components and wiring
- Ignition off
- Open the transmission control system.
Check the cable between transmission connector (transmission side) terminal #C (#A3) and solenoid SL terminal #A. Check the cable between transmission connector terminal #E (#A5) and solenoid SL terminal #B. Check these cables for a short-circuit to ground. See Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Check all the cables in the wiring harness from the transmission connector to the transmission components. Check for short-circuits to each other.
Hint: Check solenoid SL. Measure the solenoid resistance between terminals 1 and 2. The resistance must be between 3 and 5 ohms.
Remedy as necessary.
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
- To open the transmission control system, see Side cover transmission, replacing Side Cover Transmission, Replacing
- To replace solenoid S2, see Solenoid shifting 2-3, 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.
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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Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off.
- Wait at least 90 seconds.
- Reconnect the connectors, reinstall components etc.
- Ignition on.
- Gear selector in position P.
- Activate solenoid SL.
The value should change between OFF and ON.
Does the value change?
Yes - Verification completed
No - Fault-tracing information
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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 lock-up solenoid SL
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