Diagnostic Trouble Code

DTC U0101 TCM Message Unavailable

 

 

 

Circuit Highlights

 

·         Modules in this circuit are connected to the high and low speed CAN serial data circuits monitor.

·         This is done for serial data communications during normal vehicle operation.

·         Modules automatically interchange operating information and commands.

·         For every virtual network the modules receive prerecorded information about the messages needed to be exchanged on the serial data circuits.

·         These are supervised messages.

·         As an availability symbol of the transmitter module the receiver module uses some periodic messages also.

·          Every message has the identification number of the transmitter module.

 

 

 

 

When will DTC set?

When will DTC run?

Task boosted after DTC sets

When will DTC clear?

 

DTC will set when:

1)       No message received from TCM.

 

 

 

 

 

1)   When the engine remains ON.

 

 

 

 

 

1)  The Malfunction Indicator Lamp (MIL) will be seen to glow.

 

 

 

 

 

 

 

 

1)  A history DTC will unset after 40 warm up and flawless cycles.

 

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2) The ECM will store conditions from the time the diagnostic had failed.

 

2)  DTC(s) can be unset by using the scan tool.

 

 

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3)  This data will be stored in the Freeze Frame.

 

 

3)  The MIL will switch off after three repetitive validation cycles where the diagnostic runs flawlessly.

 

 

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4)  Failure Records will be boosted.

 

 

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5) A history DTC will be stored.

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Diagnostic Data

 

An improper connection, rubbed through wire insulation or a wire broken inside the insulation may start an intermittent problem. Under such a circumstance you need to inspect the trouble making circuit along with the following:

1.       Broken locks

2.       Improperly formed  or

3.       Tampered terminals

4.       Inaccurate  terminal- to- wire connection

5.       Tampered wiring harness

6.       Backed-out terminals

7.       Improper mating

 

 

 

HOW TO UNSET A DTC

DTC U0101 - TCM Message Missing

 

Step

Task To Be Done

Positive

Negative

1

Carry out the EOBD System Inspection.

 

Task done?

 

Read up  Step 2

Read up  "Diagnostic System Check"

2

  1. LOCK the ignition switch.
  2. Fix the scanner to the Data Link Connector (DLC).
  3. Now switch the ignition ON.

Can you see any DTCs shown?

 

Read up  Step 3

Try with another scan tool

3

1)       Consult the applicable DTC table.

2)        Start least numerical value and ascend accordingly.

 

Do you see that this DTC is a proper trouble code U0101?

 

Read up  Step 4

Read up  applicable DTC Table

4

  1. Once more LOCK the ignition switch.
  2. De-link the ECM and TCM.
  3. Inspect and see if there is any open or a short to ground in the wire between the TCM connector terminal A17 and ECM connector terminal 88.

Could you see any flaw at this point?

 

Read up  Step 6

Read up  Step 5

5

Inspect and see if there is any open or short to ground in the wire between the TCM connector A7 and ECM connector terminal 57.

 

Did you locate any error?

 

Read up  Step 6

Read up  Step 7

6

  1. Change the loose and twisted pair between TCM and ECM or mend the connector terminal as necessary.
  2. Taking the scanner clear all DTCs.
  3. Start the engine.
  4. Let it idle at normal operating temperature.
  5. Regulate the vehicle within the conditions for setting this DTC as specified in the supporting text.

Do you see that the scanner shows that this diagnostic has run and passed?

 

Read up  Step 9

Read up  Step 2

7

  1. Change the TCM.
  2. Clear the DTCs taking a scanner.
  3. Now start the engine.
  4. Let it idle at normal operating temperature.
  5. Regulate the vehicle within the conditions for setting this DTC as mentioned in the supporting text.

Do you see that the scanner shows that this diagnostic has run and passed?

Read up  Step 9

Read up  Step 8

8

1)       Unset all the DTCs with the help of a scan tool.

2)       Start the engine.

3)       Let the engine idle at normal operating temperature.

4)       Direct the vehicle within the conditions for setting the DTC as given.

Do you see that the scan tool shows that this diagnostic has been run and passed?

 

Read up  Step 9

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9

Probe whether any additional DTCs are set.

 

Do you see any undiagnosed DTCs still being shown?

 

Read up  applicable DTC Table

The system of the vehicle is good