For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 |

1. Remove the scan tool from the data link connector (DLC).
2. Measure the voltage between terminal 16 of the DLC and ground.

Is the voltage measured to the specified value?

B+

Go to Step 2

Go to Step 3

2 | Measure the voltage between terminal 5 and terminal 16 of the DLC. Is the voltage measured to the specified value? | B+ | Go to Step 4 | Go to Step 5
3 | Repair the open in CKT 1440 between the fuse block and the DLC. Refer to Wiring Repairs . Is the repair complete? | -- | Go to Data Link Communications System Check | --
4 | Measure the voltage between terminal 4 and terminal 16 of the DLC. Is the voltage measured to the specified value? | B+ | Go to Step 6 | Go to Step 7
5 | Repair the open in CKT 451 between the DLC and G102. Refer to Wiring Repairs . Is the repair complete? | -- | Go to Data Link Communications System Check | --
6 |

1. Reconnect the scan tool to the DLC.
2. Attempt to establish communication with each module connected to the DLC.

Can communication be established with each module?

--

Go to Data Link Communications System Check

Go to Step 8

7 | Repair the open in CKT 150 between the DLC and G201. Refer to Wiring Repairs . Is the repair complete? | -- | Go to Data Link Communications System Check | --
8 |

1. Ignition OFF, disconnect each module on the serial data circuits.
2. Ignition ON, measure the voltage between the effected DLC serial data circuit terminal and ground.

Is the voltage measured to the specified value?

0.0V

Go to Step 10

Go to Step 9

9 | Repair the short to voltage in the serial data circuit. Is the repair complete? | -- | Go to Data Link Communications System Check | --
10 | Measure the resistance between the affected DLC serial data circuit terminal and ground. Is the resistance measured to the specified value? | Infinite | Go to Step 12 | Go to Step 11
11 | Repair the short to ground in the serial data circuit. Is the repair complete? | -- | Go to Data Link Communications System Check | --
12 | Test for an open between the DLC and the first module on the serial data circuit. Was a condition found and corrected? | -- | Go to Data Link Communications System Check | Go to Step 13
13 | Test for an open or short to ground in the power circuits to each module. Was a condition found and corrected? | -- | Go to Data Link Communications System Check | Go to Step 14
14 | Test for an open in the ground circuits to each module. Was a condition found and corrected? | -- | Go to Data Link Communications System Check | Go to Step 15
15 | Reconnect each module one at a time and check for communications after each reconnect. Are communications available after each module was connected? | -- | Go to Data Link Communications System Check | Go to Step 16
16 | Replace the module that caused the condition. Is the repair complete? | -- | Go to Data Link Communications System Check | --