Signal Too Low

Signal too low

Checking the battery voltage








- Ignition on
- Read off the voltage for the transmission control module (TCM).
The voltage must be battery voltage.





Is the voltage too low?

Yes - Checking the battery voltage

No - Intermittent fault

-------------------------------------------------

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 should read 12-15 V. If the voltage is lower, check the charging system for low charge voltage.
Remedy as necessary.





Was a fault detected?

Yes - Verification

No - Checking the power supply

-------------------------------------------------

Checking the power supply




- Ignition off.
Check the transmission control module (TCM) connectors. Check for contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check the power supply cable between transmission control module (TCM) terminal #14 and the relevant sensor in the fuse/relay box in the passenger compartment. Check for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. For information about the cable routing, see the relevant Wiring Diagram.

Hint: With the ignition on and a voltmeter connected between transmission control module (TCM) terminals #14 and #15, the voltmeter must read battery voltage.

Other information:
- To connect the breakout box, see Connecting the breakout box, AW55-50/51SN Connecting The Breakout Box
- To disconnect the control module, see Replacing the transmission control module (TCM), AW55-50/51SN Service and Repair
- For information about signals, see Signal description. Transmission control module (TCM), AW55-50/51SN Signal Description.





Continue - Verification

-------------------------------------------------

Intermittent fault




- Ignition off.
Check the transmission control module (TCM) connectors. Check for contact resistance and oxidation according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.
Check the power supply cable between transmission control module (TCM) terminal #14 and the relevant sensor in the fuse/relay box in the passenger compartment. Check for an open-circuit according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults. For information about the circuit, see the relevant Wiring Diagram.

Hint: With the ignition on and a breakout box connected, the voltmeter must read battery voltage between terminals #14 and #15.

Other information:
- To connect the breakout box, see Connecting the breakout box, AW55-50/51SN Connecting The Breakout Box
- To disconnect the control module, see Replacing the transmission control module (TCM), AW55-50/51SN Service and Repair
- For information about signals see Signal description. Transmission control module (TCM), AW55-50/51SN Signal Description.





Continue - Fault-tracing information

-------------------------------------------------

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).
The voltage should be battery voltage.





Was the voltage OK?

Yes - VERIFIED

No - VERIFICATION FAILED

------------------------

VERIFIED - FAULT FOUND

VERIFICATION FAILED - Fault-tracing information

-------------------------------------------------

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

------------------------

Attempt New Test - Checking the battery voltage

-------------------------------------------------

Fault-tracing 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 - FAULT FOUND

------------------------

Attempt New Test - Checking the battery voltage

-------------------------------------------------