1. Turn OFF the ignition switch.
2. Install a scan tool.
3. Disconnect the bus bars from star connector #1 and star connector #2.
4. Connect Serial Data Link Tester J 42236 to both star connectors.

Important: Ensure the vehicle star connector #1 and #2 correctly correspond with the serial data link tester connectors #1 and #2. Refer to Data Link Connector Schematics .

5. Place the switch located on the serial data link tester in the STAR CONNECTOR #1 position.
6. Rotate the rotary switch to the (M) position.
7. Turn ON the ignition switch.
8. Use a scan tool in order to try to communicate with the BCM.

Can the scan tool communicate with the BCM?

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Go to Step 2

Go to Step 4

1. 1. Remove the ABSTRNS relay
2. Jumper ABSTRANS relay CKT 641 to BATT (CKT 970 to BATT export). Refer to Electrical Center Identification Views in Real Time Damping for circuit location.
3. Place the switch located on the serial data link tester to the STAR CONNECTOR #1 position.
4. Using a scan tool, try to communicate with each of the the following systems by rotating the rotary switch on the serial data link tester in the indicated positions:

•	(L) = HVAC

•

(J) = RFA

•	(H) = RTD (if equipped)

•

(G) = IPC

•

(E) = TCS

•	(D) = RADIO

•

(B) = PCM

Can the scan tool communicate with all the systems?

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Go to Step 3

Go to Step 7

1. Place the switch located on the serial data link tester to the STAR CONNECTOR #2 position.
2. Using a scan tool, try to communicate with each of the the following systems by rotating the rotary switch on the serial data link tester in the indicated positions:

•	(C) = LDCM

•	(D) = RDCM

•	(K) = SCM (if equipped)

Can the scan tool communicate with all the systems?

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Go to Step 9

Go to Step 7

1. Turn OFF the ignition switch.
2. Disconnect the serial data link tester J 42236.
3. Both bus bars still disconnected from star connector #1 and #2
4. Using a DMM, check for continuity between DLC terminal 2 and star connector #1 terminal A.

Is there continuity?

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Go to Step 5

Go to Step 10

Using a DMM, check for continuity between DLC terminal 2 and ground.

Is there continuity?

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Go to Step 10

Go to Step 6

1. Turn ON the ignition switch.
2. Using a DMM, measure the voltage between DLC terminal 2 and ground.

Was any voltage measured?

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Go to Step 10

Go to Step 7

1. Turn OFF the ignition switch.
2. Disconnect the system module that did not communicate with the scan tool.
3. Use a DMM to check for continuity between the applicable module terminal on star connectors and ground.

Is there continuity?

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Go to Step 11

Go to Step 8

1. Turn ON the ignition switch.
2. Connect a test light to ground.
3. Probe the applicable star connector terminal to the system module that did not communicate.

Did the test lamp light?

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Go to Step 12

Go to Step 13

Was an intermittent problem found and repaired?

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Go to Step 14

System OK

Locate and repair CKT 1132 for one of the following conditions:

Is repair complete?

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Go to Step 14

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Locate and repair a short to ground between applicable star connector terminal and the system module that did not communicate with the scan tool.

Is the repair complete?

--

Go to Step 14

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Locate and repair a short to voltage between applicable star connector terminal and the system module that did not communicate with the scan tool.

Is the repair complete?

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Go to Step 14

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Replace the system module that did not communicate with the scan tool. Refer to the appropriate module replacement procedure.

Is the replacement complete?

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Go to Step 14

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1. Turn OFF the ignition switch.
2. Reconnect or install any connector or components that were disconnected or removed.
3. Clear all communication DTCs.
4. Refer to the appropriate Diagnostic System Check for the module that did not communicate with the scan tool.

Is the repair complete?

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Go to Data Link Communications System Check

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