For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you review the Scan Tool operation and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Data Link Communications
2 | Verify that the scan tool does not communicate with one or more modules. Does the scan tool communicate with the Powertrain control module (PCM) and the brake pressure modulator valve (BPMV)? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3
3 | Attempt to establish communication with the same system on a different vehicle. Are you able to establish communication? | Go to Step 4 | Go to Step 16
4 |

1. Turn the ignition switch to the OFF position.
2. Inspect for the proper connection of the scan tool to the data link connector.

Did you find a good connection?

Go to Step 5

Go to Step 15

5 | Test for an open between cavity 5 of the data link connector (DLC) OBD 2 and ground. Did you measure an open in the BRN wire? | Go to Step 13 | Go to Step 6
6 | Test for an open between cavity 4 of the data link connector (DLC) OBD 2 and ground. Did you measure an open in the WHT/BLK wire? | Go to Step 14 | Go to Step 7
7 | Test for battery positive voltage between cavity 16 of the data link connector (DLC) OBD 2 and ground. Did you measure battery positive voltage at cavity 16? | Go to Step 8 | Go to Step 12
8 |

1. Disconnect the brake pressure modulator valve (BPMV) connector.
2. Disconnect connector C2 of the inflatable restraint sensing and diagnostic module (SDM). Refer to Disabling the SIR System .
3. Disconnect the power train control module (PCM) connector:

• | Connector C4 - with 4 spd automatic Transaxle

• | C3 - without 4 spd automatic transaxle

4. Test for a short to voltage or short to ground condition at cavity 7 of the data link connector (DLC) OBD 2.

Did you measure a short to voltage or short to ground condition at cavity 7 of the data link connector (DLC-OBD 2)?

Go to Step 10

Go to Step 9

9 |

1. Leave all of the connectors in the previous step disconnected.
2. Test for an open condition between cavity 7 of the data link connector (DLC) OBD 2 and the signal circuit of the following modules:

• | The power train control module (PCM)

• | The brake pressure modulator valve (BPMV)

Did you measure an open condition in one of the signal circuits?

Go to Step 11

Go to No Communication with EBCM in Antilock Brake System or Data Link Connector Diagnosis in Engine Controls

10 | Repair the short to ground or short to voltage condition in the WHT wire between the following components:

• | The brake pressure modulator valve (BPMV)

• | The PCM

• | The SDM

• | The data link connector (DLC) OBD 2

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 17

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11 | Repair the open condition in the WHT wire between the following components:

1. The Electronic Brake Control Module (EBCM)
2. The PCM
3. The SDM
4. The data link connector (DLC) OBD 2

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 17

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12 | Repair the open in the battery positive voltage supply circuit. Refer to Wiring Repairs in Wiring Systems Did you complete the repair? | Go to Step 17 | --
13 | Repair the open in the BRN wire between cavity 5 of the data link connector (DLC) OBD 2 and ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 17 | --
14 | Repair the open in the WHT/BLK wire between cavity 4 of the data link connector (DLC) OBD 2 and ground. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 17 | --
15 | Repair the data link connector terminal or reconnect the scan tool as necessary. Is the repair complete? | Go to Step 17 | --
16 | The scan tool may be malfunctioning. Refer to Scan Tool Instruction Manual. Is the repair complete? | Go to Step 17 | --
17 | Operate the scan tool in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3