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:
terminal #A53 (#A53) on the breakout box.

Other information:
- To connect the breakout box, see Connecting the breakout box, B5244T5, B5254T2 Connecting the Breakout Box.








ohms
The ohmmeter should read approximately 0.

OK - Checking the power supply to the control module

Not OK - contact resistance and oxidation

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Checking for open-circuits, contact resistance and oxidation
Check ground terminal 31/96 and the cable between the ground terminal and transmission control module (TCM) terminal #A53 (#A53). 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.
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.









Select Continue when the fault has been remedied.

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 #A35 (#A35) and #A53 (#A53) on the breakout box.









The voltmeter should read battery voltage.

OK - DONE

Not OK - Checking the fuse and relay

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Checking the fuse and relay
Check that fuse 20 in the fusebox in the passenger compartment is intact.
If the fuse has blown, check the cable between control module terminal #A35 (#A35) and the relay for extended X-supply 2/101 terminal #1 (located on the central electronic module (CEM)). Check for a short-circuit to ground.

Other information:
- To connect the breakout box and access the relay, see Central electronic module (CEM), replacing Central Electronic Module (CEM), Replacing
- Checking wiring and terminals Checking Wiring And Terminals









Was a fault detected?

Yes - Verification

No - Checking the voltage before the fuse

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Checking the voltage before the fuse




- Ignition on
- Connect a voltmeter between fuse 20 in the fusebox in the passenger compartment and the left socket on the fuse holder for fuse 20 and ground.
Check the following cables if the voltage is approximately 12 V. Check the cable between the fuse and relay for extended power supply 2/101 (located on the central electronic module (CEM)). Check the cable between the relay and transmission control module (TCM) terminal #A35 (#A35). Check these cables for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
If no faults were detected, try a new relay.

Other information:
- To access the relay, see Central electronic module (CEM), replacing Central Electronic Module (CEM), Replacing.









Select Continue when the fault has been remedied.

Continue - Verification

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Verification




Verification

Verification

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








- Ignition off.
- Turn of all equipment in the car that takes power from the battery (the interior lighting and radio etc).
- Control module disconnected.
Connect an ohmmeter between the battery negative terminal and terminal #A53 (#A53) on the breakout box.








ohms
The ohmmeter should read approximately 0.

OK - continued

Not OK - VERIFICATION FAILED

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Verification, continued








- Ignition off.
- Turn of all equipment in the car that takes power from the battery (the interior lighting and radio etc).
- Control module disconnected.
Connect a voltmeter between terminals #A35 (#A35) and #A53 (#A53) on the breakout box. The voltmeter should read battery voltage.









Were the ground terminal and power supply OK?

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 - FAULT-TRACING FAILED

No - Attempt New Test

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FAULT-TRACING FAILED - FAULT-TRACING FAILED

Attempt New Test - Checking the ground terminals

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