Checking the Power Supply and Ground Terminals For the Control Module

Checking the power supply and ground terminals

Checking the ground terminals








- Ignition off
- Transmission control module (TCM) disconnected.
- Turn of all equipment in the car that takes power from the battery (the interior lighting and radio etc).
Connect an ohmmeter between the battery negative terminal and:
#15 on the breakout box.

Other information:
- To connect the breakout box, see Connecting the breakout box, AW55-50/51SN Connecting The Breakout Box.









The ohmmeter should read approximately 0 ohms.

OK - Checking the power supply to the control module

Not OK - Checking for open-circuits, contact resistance and oxidation

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Checking for open-circuits, contact resistance and oxidation
Check the ground terminal and the cable between the ground terminal and transmission control module (TCM) terminal #15. Check for open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Check for contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check the ground lead between the battery and the body. Check for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Check for contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.









Continue - Verification

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Checking the power supply to the control module








- Ignition off
- Control module disconnected.
- Ignition on.
Connect a voltmeter between terminals #14 and #15 and between terminals #14 and #1 on the breakout box.









The voltmeter should read battery voltage.

OK - DONE

Not OK - Checking fuses

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Checking fuses
Check that the fuses in the fuseboxes in the passenger compartment and the engine compartment are intact.
If a fuse has blown, check the cable between control module terminal #1 and the relay in the fusebox in the engine compartment and the cable between control module terminal #14 and the fusebox in the passenger compartment. See Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
For information about the circuit, see the relevant Wiring Diagram.









Were the fuses intact?

Continue - Verification

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Verification




Verification

Hint: After the repair it is necessary to check that the fault has been rectified.








- Ignition off.
- Switch off all parts fed by the battery such as courtesy lights, radio, etc.
- Control unit disconnected.
Connect an ohmmeter between the negative battery terminal and test box #15.









The ohmmeter should show approximately 0 ( during all measurements.

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFIED - FAULT FOUND

VERIFICATION FAILED - 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 ground terminals

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