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Home >> GMC >> 2002 >> Jimmy 2D Utility, Part Time, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 1835 (Data Communication System) >> Diagnostic Information and Procedures >> Scan Tool Does Not Communicate with Keyword Data Line >> Circuit Description >> Keyword Serial Data to DLC pin 12
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Keyword Serial Data to DLC pin 12

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

Electronic brake control module (EBCM)

Scan Tool Does Not Communicate with Keyword Data Line

Step Action Yes No
Schematic Reference: Data Communication Schematics 
Connector End View Reference: Data Communication Connector End Views 
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2  Go to Diagnostic System Check - Vehicle
2
  1. Connect the scan tool to the data link connector (DLC).
  2. Turn ON the ignition, with the engine OFF.
  3. Attempt to communicate with each module on the both keyword serial data circuits:
    • Engine control module (ECM)
    • Transmission control module (TCM)
    • Electronic brake control module (EBCM)
Does the scan tool communicate with all the modules on the keyword serial data circuit?		 Go to Testing for Intermittent Conditions and Poor Connections Go to Step 3 
3
  1. Disconnect the scan tool from the DLC.
  2. Turn OFF the ignition.
  3. Disconnect all non-communicating modules on the respective keyword serial data circuit.
  4. Turn ON the ignition, with the engine OFF.
  5. Test the respective keyword serial data circuit between the DLC and the modules on the keyword serial data circuit, for the following conditions:
    • An open
    • A short to ground
    • A short to voltage
Refer to the following:Did you find and correct the condition?		 Go to Step 9  Go to Step 4 
4
IMPORTANT: Perform the following 2 steps if the scan tool didn't communicate with both ECM and TCM. Otherwise skip to step 6.
  1. Reconnect the TCM.
  2. Turn ON the ignition with the engine OFF.
  3. Attempt to communicate with TCM.
Does the scan tool communicate with TCM?		 Go to Step 5  Go to Step 6 
5 Consider the ECM as non communicating module for the following steps. Go to Step 6  -
6 Test the following circuits of the module that is not communicating for an open or high resistance:
  • The battery positive voltage input circuits
  • The battery positive voltage output circuits
  • The ignition voltage input circuits
  • The ignition voltage output circuits
  • The switched battery positive voltage supply circuits
  • The ground circuits

Refer to the following:
Did you find and correct the condition?		 Go to Step 9  Go to Step 7 
7 Inspect for poor connections and terminal tension at the following harness connector circuits of the module that is not communicating :
  • The battery positive voltage input circuits
  • The battery positive voltage output circuits
  • The ignition voltage input circuits
  • The ignition voltage output circuits
  • The switched battery positive voltage supply circuits
  • The ground circuits
  • The Keyword serial data circuits

Refer to the following:
Did you find and correct the condition?		 Go to Step 9  Go to Step 8 
8 Replace the module that is not communicating on the Keyword serial data circuit. Refer to Control Module References for replacement, setup and programming.
Did you complete the replacement?		 Go to Step 9  -
9
  1. Connect all modules and connectors.
  2. Connect the scan tool to the DLC.
  3. Turn ON the ignition, with the engine OFF.
  4. Attempt to communicate with all modules on keyword serial data circuits.
Does the scan tool communicate with all the modules on the keyword serial data circuits?		 System OK Go to Step 2 
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