Scan Tool Does Not Communicate with Class 2 Data Line. Cadillac DeVille 1998

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 1998 🢒 DeVille 🢒 Body and Accessories 🢒 Seats 🢒 Scan Tool Does Not Communicate with Class 2 Data Line

Step

Action

Value(s)

Yes

Did you perform the Data Link Communication Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Data Link Communications

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

Does the scan tool communicate with the vehicle?

Go to Step 4

Go to Step 3

The scan tool may be malfunctioning. Refer to the scan tool instruction manual in order to ensure that the scan tool is functional.

Does the scan tool operate properly?

Go to Diagnostic System Check - Data Link Communications

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

Is the terminal contact between the data link connector (DLC) and the scan tool OK?

Go to Step 6

Go to Step 5

Repair the terminal contact at the DLC. Refer to Connector Repairs .

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Turn the ignition switch to RUN with the engine OFF.

Does the scan tool turn on?

Go to Step 12

Go to Step 7

Measure the voltage between the 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

Repair the open or the short to ground in CKT 1740 (ORN). Refer to Wiring Repairs .

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Measure the 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

Repair the open in CKT 51 (BLK/WHT). Refer to Wiring Repairs .

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Disconnect the powertrain control module (PCM).
Attempt to establish communication with the body control module (PZM).

Does the scan tool communicate with the vehicle?

Go to Step 12

Go to Step 13

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls.

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Disconnect the electronic brake and traction control module (EBTCM).
Attempt to establish communication with the PZM.

Does the scan tool communicate with the vehicle?

Go to Step 14

Go to Step 16

Test CKT 1807 (PPL) between the EBTCM C2 terminal 10 and the PCM C1 terminal 58 for a short to ground or to battery positive voltage (B+).

Did you find a short?

Go to Step 54

Go to Step 15

Replace the EBTCM.

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Disconnect the radio.
Attempt to establish communication with the PZM.

Does the scan tool communicate with the vehicle?

Go to Step 17

Go to Step 18

Replace the radio. Refer to one of the flowing:

•	Radio Replacement

•	Radio Replacement

in Entertainment.

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Disconnect the instrument cluster.
Attempt to establish communication with the PZM.

Does the scan tool communicate with the vehicle?

Go to Step 19

Go to Step 20

Replace the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges, and Console.

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Is the vehicle equipped w/D55?

Go to Step 21

Go to Step 24

Disconnect the climate control panel (CCP).
Attempt to establish communication with the PZM.

Does the scan tool communicate with the vehicle?

Go to Step 22

Go to Step 24

Test CKT 1807 (PPL) for a short to ground or battery positive voltage (B+) between the instrument cluster C3 terminal D1 and the CCP terminal A8.

Did you find a short in the circuit?

Go to Step 54

Go to Step 23

Replace the CCP.

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Is the vehicle equipped w/A45?

Go to Step 25

Go to Step 28

Disconnect the memory mirror module (MMM).
Attempt to establish communication with the PZM.

Does the scan tool communicate with the vehicle?

Go to Step 26

Go to Step 28

Test CKT 1807 (PPL) for a short to ground or battery positive voltage (B+) between the MMM C1 terminal E16 and the instrument cluster C3 terminal D1 (w/o D55) and the CCP (w/D55).

Did you find a short in the circuit?

Go to Step 54

Go to Step 27

Replace the MMM.

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Disconnect the heater and A/C programmer.
Attempt to establish communication with the PZM.

Does the scan tool communicate with the vehicle?

Go to Step 29

Go to Step 30

Test CKT 1807 (PPL) for a short to ground or to battery positive voltage (B+) between the heater and the A/C programmer C2 terminal D2 and the following component:

•	The MMM C1 terminal F16 (w/A45)

•	The CCP terminal B8 (w/D55 and w/o A45)

•	The instrument cluster C3 terminal D1 (w/o A45 and w/o D55)

Did you find a short in the circuit?

Go to Step 54

Go to Step 55

Is the vehicle equipped with the cellular telephone module?

Go to Step 31

Go to Step 33

Disconnect the cellular telephone module.
Attempt to establish communication with the PZM.

Does the scan tool communicate with the vehicle?

Go to Step 32

Go to Step 33

Replace the cellular telephone module.

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Is the vehicle equipped w/A45?

Go to Step 34

Go to Step 36

Disconnect the memory seat module (MSM).
Attempt to establish communication with the PZM.

Does the scan tool communicate with the vehicle?

Go to Step 35

Go to Step 36

Test CKT 1807 (PPL) for a short to ground or to battery positive voltage (B+) between the MSM C1 terminal 26 and the radio terminal E6.

Did you find a short in the circuit?

Go to Step 54

Go to Step 56

Disconnect the inflatable restraint sensing and diagnostic module (SDM).
Attempt to establish communication with the PZM.

Does the scan tool communicate with the vehicle?

Go to Step 37

Go to Step 39

Test CKT 1807 (PPL) for a short to ground or battery positive voltage (B+) between the SDM terminal 17 and the following component:

•	The MSM C1 terminal 25 (w/o A45)

•	The radio terminal E6 (w/ A45)

Did you find a short in the circuit?

Go to Step 54

Go to Step 38

Replace the SDM.

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Is the vehicle equipped w/F45?

Go to Step 40

Go to Step 42

Disconnect the continuously variable road sensing suspension (CVRSS) module.
Attempt to establish communication with the PZM.

Does the scan tool communicate with the vehicle?

Go to Step 41

Go to Step 42

Replace the CVRSS module.

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Is the vehicle equipped w/ UQ4 or w/ UQ6?

Go to Step 43

Go to Step 47

Disconnect the following component:

•	The radio amplifier (DeVille)

•	The radio interface module (RIM) (Eldorado)

Attempt to establish communication with the PZM.

Does the scan tool communicate with the vehicle?

Go to Step 44

Go to Step 47

Is the vehicle equipped w/ F45?

Go to Step 45

Go to Step 47

Test CKT 1807 (PPL) for a short to ground or to battery positive voltage between the CVRSS module C1 terminal D5 and the following components:

•	The radio amplifier C1 terminal B2 (DeVille)

•	The RIM C1 terminal B2 (Eldorado)

Did you find a short in the circuit?

Go to Step 54

Go to Step 46

Replace the following component:

•	The radio amplifier (Deville)

•	The RIM (Eldorado)

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Disconnect the remote function actuator (RFA).
Attempt to establish communication with the PZM.

Does the scan tool communicate with the vehicle?

Go to Step 48

Go to Step 51

Is the vehicle equipped with F45, UQ4, or UQ6?

Go to Step 49

Go to Step 50

Test CKT 1807 (PPL) for a short to ground or to battery positive voltage (B+) between the RFA module terminal 2 and the following component:

•	The CVRSS module C1 terminal D5 (w/F45 and w/o UQ4 or UQ6)

•	The RIM C1 terminal B3 (Eldorado)

•	The radio amplifier C1 terminal B3 (DeVille)

Did you find a short in the circuit?

Go to Step 54

Go to Step 50

Replace the RFA module.

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Reconnect the instrument cluster.
Disconnect the PZM.
Attempt to establish communication with the instrument cluster.

Does the scan tool communicate with the vehicle?

Go to Step 52

Go to Step 54

Test CKT 1801 (PPL) for a short to ground or to battery positive voltage (B+) between the PZM C1 terminal A2 and the RFA module terminal 3.

Did you find a short in the circuit?

Go to Step 54

Go to Step 53

Replace the PZM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Repair the open, the short to ground, or the short to battery positive voltage (B+) in CKT 1807 (PPL). Refer to Wiring Repairs .

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Replace the heater and A/C programmer.

DId you complete the repair?

Go to Diagnostic System Check - Data Link Communications

Replace the MSM. Refer to Memory Seat Control Module Replacement in Seats.

Did you complete the repair?

Go to Diagnostic System Check - Data Link Communications