FC. Communications Problems With the Data Link Connector

FC. Communications problems with the Data Link Connector DLC (DLC A).

Fault-tracing information

Operating basics:






- Normal supply voltage to the system
- Charging system operating normally
- The fault is permanent.


Defect cause:

- Break in signal wiring
- Short circuit to ground in the signal wiring.
- Contact resistance in terminals
- Break on the 15 supply to the TCM
- Break on the 30 supply to the TCM
- Break on signal and power ground to TCM
- Malfunction in DLC.

- Fault-tracing starts with FC1.



FC1

Checking ground points






- Ignition OFF
- Connect test box and check ground points as per GB1-GB2 GB. Connecting the Test Box

If the ground points are OK as per GB2: GB. Connecting the Test Box

- Checking supply voltage (15 supply) FC2.


FC2

Checking supply voltage (15 supply)






- Ignition ON.

Use a voltmeter to measure between #30 (#A30) and #29 (#A29) on the test box.
The voltmeter should register approx. battery voltage.

If reading is OK:
- Checking supply voltage (30 supply) FC3.

If reading is incorrect:
- Check the cable between fuse 11/1 and the transmission control module TCM #A30 for breaks as per FA2. FA. Checking Wiring and Connections

Then continue with: Checking supply voltage (30 supply) FC4.


FC3

Checking supply voltage (30 supply)






- Ignition ON.

Use a voltmeter to measure between #10 (#A10) and #20 (#A20) on the test box.
The voltmeter should register approx. battery voltage.

If reading is OK:
- Checking the LEDs on the Data Link Connector (DLC) FC4.


If reading is incorrect:
- Check the cable between the positive terminal on the battery and transmission control module (TCM) #A1O for breaks as per FA2. FA. Checking Wiring and Connections



FC4

Checking the LEDs on the Data Link Connector (DLC)






- Ignition ON.
- Selector cable not connected
- Press button on DLC.

LED should light when button is pressed.

If LED lights:
- Check selector cable as per FC7

If LED does not light:
- Checking power supply FC5.


FC5

Checking power supply






- Ignition OFF
- Disconnect the DLC connector Ignition ON.

Connect a voltmeter between the DLC connector terminal 4 and ground.
The voltmeter should register approx. battery voltage.

If reading is OK:
- Checking ground wiring FC6.

If reading is incorrect:
- Check that fuse 11/33 is intact.
- Check the cable between the DLC connector terminal 4 and fuse 11/33 for breaks in the circuit as per FA2. FA. Checking Wiring and Connections



FC6

Checking ground wiring






- Ignition OFF
- Data Link Connector (DLC) disconnected. Connect an ohmmeter between the DLC connector terminal 8 and ground.

The ohmmeter should read approx. 0 Ohms.

If reading is OK:
- Repeat test with new DLC.

If reading is incorrect:
- Check ground point 31/50 and the cable between the DLC connector terminal 8 and ground point 31/50 for breaks in the circuit as per FA2. FA. Checking Wiring and Connections



FC7

Checking the adapter cable






- Ignition OFF
- Selector cable not connected

Connect an ohmmeter between selector cable probe and ground.

- Press button on data link connector DLC.

The ohmmeter should read approx. 0 Ohms.

If reading is OK:
- Checking diagnostic wiring resistance to ground FCB.

If reading is incorrect:
- Repeat test with new DLC.



FC8

Checking diagnostic wiring resistance to ground






- Ignition OFF
- Disconnect the data link connector (DLC)
- Disconnect TCM

Connect an ohmmeter between the DLC connector terminal 1 (A1) and ground.
The ohmmeter should read infinite resistance.

If reading is OK:
- Checking diagnostic wiring FC9.

If reading is incorrect:
- Check the cable between the DLC connector terminal 1 (A1) and the TCM #B5 for short circuit to ground as per FA3. FA. Checking Wiring and Connections



FC9

Checking diagnostic wiring






- Ignition OFF
- Connect TCM
- Ignition ON.

Connect a voltmeter between the DLC connector terminal 1 (A1) and ground.
The voltmeter should register approx. 1 - 4 V below battery voltage.

If reading is OK:
- The DTC was set because of poor contact in the TCM connector.

If the voltmeter reads approx. 0 V:
- Check the cable between the DLC connector terminal 1 (A1) and the TCM #B5 for breaks in the circuit as per FA2. FA. Checking Wiring and Connections

If the voltmeter reads approx. battery voltage:
- Check the cable between the DLC connector terminal 1 (A1) and the TCM #B5 for short circuit to supply as per FA3. FA. Checking Wiring and Connections