For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Data Link Connector Schematics
1 | Perform the Diagnostic System Check for the system exhibiting symptoms. Refer to Control Module References in Body Control System. Did you perform the Diagnostic System Check for the system exhibiting symptoms? | Go to Step 2 | Go to the Diagnostic System Check for the system exhibiting symptoms. Refer to Control Module References in Body Control System
2 |

1. Connect the scan tool to the DLC.
2. Turn ON the ignition, with the engine OFF.
3. Attempt to communicate with each of the Keyword serial data communications device circuits:

• | Automatic Level Control Sensor

• | Sun Roof Actuator and Theft Deterrent Module

• | SDM, Power Steering Control Module, Heater and A/C Control, EBCM

• | TCM, Driver Seat Adjuster Memory Module, IPC, ECM

Does the scan tool communicate with all Keyword serial data communications devices?

Go to Testing for Intermittent Conditions and Poor Connections In Wiring Systems

Go to Step 3

3 |

1. Disconnect the scan tool from the DLC.
2. Disconnect any non-communicating modules on the keyword serial data circuit that exhibited a communications concern.
3. Test the Keyword serial data communications circuit(s) for an open between the DLC and any device. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct a serial data circuit condition?

Go to Step 7

Go to Step 4

4 | Test the battery power, switched battery power, ignition positive and ground circuits of the module(s) that fail to communicate with the scan tool. Refer to Power Distribution Schematics , Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 7 | Go to Step 5
5 | Inspect the harness connector(s) of the non-communicating module(s) containing the battery positive, ignition positive, ground and keyword serial data communications circuits. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 7

Go to Step 6

6 | Important: Perform the set up procedure for the module being replaced, if required Replace the module that is not communicating on the Keyword serial data communications circuit. Refer to Control Module References in Body Control System. Did you complete the replacement? | Go to Step 7 | --
7 |

1. Reconnect any connectors that were disconnected.
2. Connect the scan tool to the DLC.
3. Turn ON the ignition, with the engine OFF.
4. Perform the Diagnostic System Check for the system exhibiting symptoms. Refer to Control Module References in Body Control System.

Did you complete the operation?

System OK

Go to Step 2