Captiva

Scan Tool Does Not Communicate with Keyword Data Line

The Keyword protocol utilises a single wire bi-directional data line between the control modules and the scan tool. The message structure is a request and response arrangement. The Keyword serial data is used for scan tool diagnostics only. The control modules do not exchange data on this circuit.

Schematic Reference

Data Communication Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Data Link Communications Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Note: Use the schematic to identify the following:

1. Ignition OFF, disconnect the harness connector at a control module that is not communicate with the Keyword serial data circuit.
2. Test for less than 1 Ω between each ground circuit terminal and ground.

⇒	If greater than the specific range, test the ground circuit for an open/high resistance.

3. If equipped, ignition ON, verify that a test lamp illuminates between each B+ circuit terminal and ground.

⇒

If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and fuse is open, test the positive voltage outputs of the control module for a short to ground. If all circuits test normal, replace the non communicating control module.

4. If equipped, ignition ON, verify that a test lamp illuminates between each ignition circuit terminal and ground.
5. Test for less than 1 V between the DLC serial data circuit terminal 7 and ground.

⇒	If greater than the specified range, test each section of the serial data circuit for a short to voltage. If the circuits test normal, replace the control module that causes the short to voltage when connected.

6. Test for infinite resistance between the DLC serial data circuit terminal 7 and ground.

⇒	If less than the specified value, test each section of the serial data circuit for a short to ground. If the circuits test normal, replace the control module that causes the short to ground when connected.

7. Test for less than 1 Ω between the DLC serial data circuit terminal 7 and the serial data circuit terminal at the non communicating control module.

⇒	If greater than the specified range, test the serial data circuit for open/high resistance.

8. If all circuits test normal, replace the non communicating control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for control module replacement, setup, and programming