For 1990-2009 cars

### Circuit Description

The Keyword 2000 serial data link allows information to be exchanged from module to module as needed. This is done by the ECM, the ECM requests and sends all the information that is transmitted on the Keyword 2000 line. When a scan tool is connected to the Keyword line it takes over for the ECM and sends and requests the needed information.

### Diagnostic Aids

• | Thoroughly inspect the wiring and the connectors. Failure to carefully and fully inspect the wiring and the connectors can result in misdiagnosis. Misdiagnosis may cause replacement of parts without repairing the malfunction.

• | If an intermittent malfunction exists, refer to Intermittents and Poor Connections in Wiring Systems.

### Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

1. This step checks if the scan tool can communicate with other modules on the Keyword 2000 serial data line. If the scan tool can communicate with other modules, then the malfunction is likely with the ignition input, ground or the serial data line to the EBTCM.

#### No Communication with EBTCM

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
DEFINITION: Scan tool can not communicate with the EBTCM. SCHEMATIC REFERENCE:

#### EBCM Power, Ground, and DLC

1 | Was the Diagnostic System Check performed? | -- | Go to Step 2 | Go to Diagnostic System Check - ABS
2 | Turn the Ignition switch to the ON position with the engine off. Can the scan tool communicate with other modules on the Keyword 2000 serial data line, such as the ECM? | -- | Go to Step 3 | Go to Scan Tool Does Not Communicate with Class 2 Data Line in Data Link Communications
3 | Inspect the 10A ABS Fuse 19 in the Fuse Block. Is the fuse OK? | -- | Go to Step 4 | Go to Step 6
4 |

1. Install the fuse if removed.
2. Turn the ignition switch to the ON position, engine off.
3. Using J 39200 DMM, measure the voltage at the 10A ABS Fuse 19 by probing between the fuse test terminals and a good ground.

Is the voltage within the range specified within the value(s) column?

Battery Volts

Go to Step 5

Go to Power Distribution Schematics in Wiring Systems

5 |

1. Turn the ignition switch to the OFF position.
2. Disconnect the EBTCM connector C1.
3. Connect the J 39700 Universal Pinout Box using the J 39700-280 cable adapter to the EBTCM harness connector C1 only.
4. Using J 39200 DMM, measure the resistance between J 39700 terminal 19 and a good ground.

Is the resistance within the range specified in the value(s) column?

0 - 5ohms

Go to Step 10

Go to Step 9

6 |

1. Install a new 10A ABS Fuse 19.
2. Turn the ignition switch from the OFF to ON position, engine off.
3. Recheck the fuse.

Is the fuse OK?

--

Go to Diagnostic System Check - ABS

Go to Step 7

7 |

1. Turn the ignition switch to the OFF position.
2. Remove the 10A ABS Fuse 19.
3. Disconnect the EBTCM connector C1.
4. Connect the J 39700 Universal Pinout Box using the J 39700-280 cable adapter to the EBTCM harness connector C1 only.
5. Using J 39200 DMM, measure the resistance between terminals 15 and 19 of J 39700 .

Is the resistance within the range specified in the value(s) column?

OL (infinite)

Go to Step 12

Go to Step 8

8 | Repair CKT FA202 for a short to ground. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
9 | Repair the ground circuit or G103 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
10 |

1. Turn the ignition switch to the ON position, engine off.
2. Using J 39200 DMM, measure the voltage between J 39700 terminals 15 and 19.

Is the voltage within the range specified in the value(s) column?

Battery Volts

Go to Step 13

Go to Step 11

11 | Repair CKT FA202 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
12 | Replace the EBTCM. Refer to Electronic Brake and Traction Control Module Replacement . Is the replacement complete? | -- | Go to Diagnostic System Check - ABS | --
13 |

1. Turn the ignition switch to the OFF position.
2. Using J 39200 DMM, measure the resistance between the J 39700 terminal 11 and the DLC terminal 12.

Is the resistance within the range specified in the values column?

0-5ohms

Go to Step 12

Go to Step 14

14 | Repair the Keyword 2000 serial data circuit for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --