For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Data Link Connector System Check performed? | -- | Go to Step 2 | Go to Data Link Communications System Check
2 |

1. Connect the scan tool to another vehicle of the same model year in order to ensure proper operation of the scan tool.
2. Turn the ignition switch to RUN.
3. Attempt to establish communication with the vehicle.

Does the scan tool communicate with the vehicle?

--

Go to Step 4

Go to Step 3

3 | The scan tool may be malfunctioning. Refer to the scan tool instruction manual. Ensure that the scan tool is functioning. Does the scan tool operate properly? | -- | Go to Data Link Communications System Check | --
4 |

1. Turn the ignition switch OFF.
2. Connect the scan tool to the original vehicle.
3. Verify that the scan tool connections are clean and tight.

Is the terminal contact between the DLC and the scan tool OK?

--

Go to Step 6

Go to Step 5

5 | Repair the terminal contact at the DLC. Is the repair complete? | -- | Go to Data Link Communications System Check | --
6 | Turn the ignition switch to RUN with the engine OFF. Does the scan tool turn ON? | -- | Go to Step 12 | Go to Step 7
7 | Using a DMM, measure the voltage between DLC terminal 16 and the chassis ground. Is the voltage within the specified range? | 10-15 V | Go to Step 9 | Go to Step 8
8 | Repair the open or the short to ground in CKT 40 (ORN). Is the repair complete? | -- | Go to Data Link Communications System Check | --
9 | Measure voltage from DLC terminal 16 to terminal 5. Is the voltage within the specified range? | 10-15 V | Go to Step 11 | Go to Step 10
10 | Repair the open in CKT 451 (BLK/WHT). Is the repair complete? | -- | Go to Data Link Communications System Check | --
11 | Repair the open in CKT 1250 (BLK). Is the repair complete? | -- | Go to Data Link Communications System Check | --
12 | Measure the voltage from DLC terminal 2 to ground. Is the voltage within the specified range? | 10-15 V | Go to Step 15 | Go to Step 13
13 | Using a DMM, measure the resistance from DLC terminal 2 to ground. Is the resistance within the specified range? | 0-5 ohms | Go to Step 20 | Go to Step 14
14 | Repair the open in CKT 1807 (PPL) between DLC terminal 2 and S278. Is the repair complete? | -- | Go to Data Link Communications System Check | --
15 |

1. Disconnect the PCM.
2. Measure the voltage from DLC terminal 2 to ground.

Is the voltage within the specified range?

10-15 V

Go to Step 17

Go to Step 16

16 | Replace the PCM. Is the repair complete? | -- | Go to Data Link Communications System Check | --
17 |

1. Disconnect the RFA.
2. Measure the voltage from DLC terminal 2 to ground.

Is the voltage within the specified range?

10-15 V

Go to Step 19

Go to Step 18

18 | Replace the RFA. Is the repair complete? | -- | Go to Data Link Communications System Check | --
19 | Repair the short to battery positive voltage (B+) in CKT 1807 (PPL). Is the repair complete? | -- | Go to Data Link Communications System Check | --
20 |

1. Disconnect the PCM.
2. Measure the resistance from DLC terminal 2 to ground.

Is the resistance within the specified range?

0-5 ohms

Go to Step 21

Go to Step 22

21 | Replace the PCM. Is the repair complete? | -- | Go to Data Link Communications System Check | --
22 |

1. Disconnect the RFA.
2. Measure the resistance from DLC terminal 2 to ground.

Is the resistance within the specified range?

0-5 ohms

Go to Step 23

Go to Step 24

23 | Replace the RFA. Is the repair complete? | -- | Go to Data Link Communications System Check | --
24 | Repair the short to ground in CKT 1807 (PPL). Is the repair complete? | -- | Go to Data Link Communications System Check | --