4T65EV Transmission
Signal too low
Checking the battery voltage
- Ignition on
- Read off the voltage for the transmission control module (TCM) and the central electronic module (CEM).
The voltage must be battery voltage for both the control modules.
Select an option:
1. Voltage too low for both control modules
2. Voltage too low for the transmission control module (TCM).
Select an alternative.
1 - Checking the battery voltage
2 - Checking the power supply
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Checking the battery voltage
- Start the engine and let it run at idle speed
- Connect a voltmeter between the battery positive and negative terminals.
The voltmeter must read 12-15 V. If the voltage is lower, check the charging system. Check for low charge voltage.
Was a fault detected?
Yes - Verification
No - Checking the battery terminals
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Checking the battery terminals
Check the battery positive and negative terminals and the front terminals in the engine compartment. Check for contact resistance and oxidation.
Remedy as necessary.
Continue - Fault-tracing information
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Fault-tracing information
Information
Fault-tracing information
The fault should be diagnosed and remedied. Since this is not the case the fault-tracing process has failed.
Complete the fault-tracing for those fault or try again.
Do you want to terminate fault-tracing at this time?
Yes - Exit fault-tracing
No - Attempt New Test
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Attempt New Test - Checking the battery voltage
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Checking the power supply
- Ignition off.
Check the control module connector. Check for contact resistance and oxidation.
Check the power supply cable. Check for an intermittent open-circuit.
Other information:
- To connect the breakout box, see Connecting the breakout box, B5254T2 Connecting the Test Box
- For information about signals, see Signal specification, 4T65EV-GT Signal Specification
- Checking wiring and terminals Checking Wiring And Terminals
Was a fault detected?
Yes - Verification
No - Checking the control module
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Checking the control module
- The breakout box connected
- Ignition on
- Read off the voltage
- Connect a voltmeter between terminals #35 (#A35) and #53 (#A53) on the breakout box. The voltage must be normal system voltage.
Compare the power supplies with each other.
The difference between the read off voltage and the voltmeter voltage must not exceed 1.5 V. If the difference is greater, replace the control module.
Other information
- To connect the breakout box, see Connecting the breakout box, B5254T2 Connecting the Test Box
- For information about signals, see Signal specification, 4T65EV-GT Signal Specification
- To replace the transmission control module (TCM), see Signal specification, 4T65EV-GT Signal Specification.
Was the difference greater than 1.5V?
Yes - Verification
No - Diagnostic trouble code (DTC) information
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Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition on.
- Read off the voltage for the transmission control module (TCM) and the central electronic module (CEM).
The voltage must be battery voltage for both the control modules.
Was the voltage OK?
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 the battery voltage
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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 battery voltage
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