Captiva |
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• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
B+ | 1 | 1 | -- | -- |
Ignition | 1 | 1 | -- | -- |
Serial Data | 1 | 1 | 1 | -- |
Ground | -- | 1 | -- | -- |
1. Scan tool does not communicate with Keyword device |
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.
Data Link Communications Description and Operation
Control Module References for scan tool information
Note: Use the schematic to identify the following: • Control modules the vehicle is equipped with • Control module location on the Keyword serial data circuit • The B+, ignition, ground, and Keyword serial data circuit terminals for each control module
⇒ | If greater than the specific range, test the ground circuit for an open/high resistance. |
⇒ | 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. |
⇒ | 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. |
⇒ | 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. |
⇒ | If greater than the specified range, test the serial data circuit for open/high resistance. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for control module replacement, setup, and programming
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