Was the Data Link Communications System Check performed?

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Go to Step 2

Refer to Data Link Communications System Check

Does the scan tool power up?

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Go to Step 10

Go to Step 3

1. Disconnect the scan tool from the data link connector (DLC).
2. Inspect for proper connection of the scan tool to the DLC at terminal 4 and terminal 16.

Inspect with a known good male terminal from J-38125 repair kit.

Is the connection good?

--

Go to Step 4

Go to Step 6

Measure voltage from terminal 16 of the DLC to ground.

Does voltage equal the specified value?

12.0 B+

Go to Step 5

Go to Step 8

Measure the resistance from terminal 4 of the DLC to ground.

Is the resistance within the specified range?

0-5 ohms

Go to Step 7

Go to Step 9

Repair the connection as needed.

Is the repair complete?

--

Refer to Data Link Communications System Check

Go to Step 3

Inspect the scan tool for a malfunction. Refer to the Scan Tool instruction manual.

Has a properly operating scan tool been obtained?

--

Go to Step 2

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Repair an open in CKT 640 (ORN).

Is the repair complete?

--

Refer to Data Link Communications System Check

--

Repair an open in CKT 1850 (BLK).

Is the repair complete?

--

Refer to Data Link Communications System Check

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1. Turn the ignition switch to the RUN position.
2. Use the scan tool in order to attempt to establish communication with each module on the Class 2 data link.

If you use a Tech 2, use the Diagnostic Circuit Check CLASS 2 MESSAGE MONITOR feature in order to obtain this information.

Are any of the modules on the Class 2 data link communicating?

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Go to Step 11

Go to Step 14

Is DTC U1000 or DTC U1xxx (lost communications with xxx) set in the modules that will communicate?

--

Go to Step 12

Go to Step 13

Use the CLASS 2 LOST COMMUNICATIONS WITH XXX (U1000) procedures, as appropriate, in order to diagnose the malfunction

Is the procedure complete?

--

Refer to Data Link Communications System Check

--

Use the CLASS 2 LOST COMMUNICATIONS WITH XXX (U1XXX) procedures in order to diagnose the malfunction for the module which is not communicating.

Is the procedure complete?

--

Refer to Data Link Communications System Check

--

1. Turn the ignition switch to the OFF position.
2. Inspect for proper connection of the scan tool to the DLC at terminal 5.

Inspect with known good male terminal from repair kit J-38125.

Is the connection good?

--

Go to Step 15

Go to Step 6

Measure the voltage from terminal 16 to terminal 5 of the DLC.

Is the voltage within the specified range?

0-5 ohms

Go to Step 16

Go to Step 28

Check for proper connection of the scan tool to the DLC at terminal 2.

Inspect with known good male terminal from repair kit J-38125.

Is the connection good?

--

Go to Step 17

Go to Step 6

Measure the resistance from terminal 2 of the DLC to splice S201.

Is the resistance within the specified range?

0-5 ohms

Go to Step 18

Go tp Step 27

Measure the resistance on the DLC from terminal 2 to terminal 4.

Is the resistance as specified?

OL (Infinite)

Go to Step 19

Go to Step 26

1. Turn the ignition switch to the RUN position.
2. Measure the voltage on the DLC from terminal 2 to terminal 4.

Is the voltage within the specified range?

0-1 V fluctuating

Go to Step 20

Go to Step 25

1. Turn the ignition switch to the OFF position.
2. Disconnect the module which does not communicate with the scan tool.
3. Measure the resistance from splice 201 of the Class 2 serial data circuit for the disconnected module to ground.

Is the resistance as specified?

OL (Infinite)

Go to Step 21

Go to Step 26

1. Turn the ignition switch to the RUN position.
2. Measure the voltage from the Class 2 serial data circuit of the disconnected module to ground.

Is the voltage within the specified range?

0-1 V fluctuating

Go to Step 22

Go to Step 25

1. Turn the ignition switch to the OFF position.
2. Inspect the connector of the disconnected module in the area of the Class 2 serial data circuit for backed out terminals that may cause a short to ground or voltage.

Are all terminals properly locked in to the connector body?

--

Go to Step 23

Go to Step 6

1. Replace the module that does not communicate.

Refer to the appropriate on-vehicle service procedures for the module being replaced in order to ensure a complete repair.

2. Reconnect all the modules on the Class 2 serial data link.
3. Turn the ignition switch to the RUN position.
4. Use the scan tool in order to attempt to establish communication with the module which was replaced.

Can communications be established?

--

Go to Step 29

Go to Step 24

Replace the Class 2 serial data circuit wire between splice 201 and the module that does not communicate.

Is the repair complete?

--

Go to Step 29

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1. Turn the ignition switch to the OFF position.
2. Repair the short to voltage in the Class 2 serial data circuit.

Is the repair complete?

--

Go to Step 29

--

Repair the short to ground in the Class 2 serial data circuit.

Is the repair complete?

--

Go to Step 29

--

Repair the open in the Class 2 serial data circuit.

Is the repair complete?

--

Refer to Data Link Communications System Check

--

Repair the open in CKT 451 (BLK/WHT).

Is the repair complete?

--

Refer to Data Link Communications System Check

--

1. Reconnect all the modules on the Class 2 serial data link.
2. Turn the ignition switch to the RUN position.
3. Wait for 10 seconds.
4. Inspect for DTCs in each module on the Class 2 serial data link.

Do any DTCs exist that begin with a U set with a current status?

--

Go to Step 31

Go to Step 30

Are any DTCs set that do not begin with a U?

--

Go to Step 31

Go to Step 32

Diagnose the DTCs as directed by the diagnostic procedures for the particular module or malfunction.

Is the procedure complete?

--

Go to Step 32

--

Have all DTCs been diagnosed?

--

Go to Step 33

Go to Step 30

Clear all of the DTCs.

Is the repair complete?

--

Refer to Data Link Communications System Check

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