GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1998 🢒 DeVille 🢒 Body and Accessories 🢒 Entertainment 🢒 Cellular Telephone Inoperative

Step

Action

Value(s)

Yes

No

1

Turn the ignition to the RUN position.

Does the vehicle radio work?

--

Go to Step 2

Go to Step 3

2
  1. Turn the ignition to the OFF position.
  2. Disconnect the cellular telephone module harness connector.

    3. Turn the ignition to the RUN position.

  3. in order to set to DC scale and measure the voltage between the cellular telephone module connector terminal A and ground, use a J 39200 digital multimeter (DMM).

Is battery voltage present?

B+

Go to Step 4

Go to Step 5

3

Inspect the rear compartment fuse block radio/phone fuse.

Is the fuse OK?

--

Go to Step 6

Go to Step 7

4

Use a J 39200 DMM in order to measure the voltage between the cellular telephone module connector terminal  A and B.

Is battery voltage present?

B+

Go to Step 8

Go to Step 9

5

Repair the open in CKT 40 (ORN).

Is the repair complete?

--

Go to Cellular Telephone System Check

--

6
  1. Turn the ignition to the RUN position.
  2. Disconnect the cellular telephone module.
  3. in order to set to DC scale and inspect for voltage at the cellular telephone module connector terminal A, use a J 39200 DMM .

Is battery voltage present?

B+

Go to Step 10

Go to Step 11

7

Repair the short to ground in CKT 40 (ORN).

Is the repair complete?

--

Go to Cellular Telephone System Check

--

8

Is the vehicle equipped with a fixed type of cellular telephone?

--

Go to Step 12

Go to Step 13

9

Repair the open in CKT 1051 (BLK).

Is the repair complete?

--

Go to Cellular Telephone System Check

--

10

Use a J 39200 DMM in order to measure the voltage between the cellular telephone module connector terminals A and B.

Is battery voltage present?

B+

Go to Step 14

Go to Step 15

11

Repair the open in CKT 40 (ORN).

Is the repair complete?

--

Go to Cellular Telephone System Check

--

12
  1. Disconnect the harness connector from the cellular telephone handset interface.
  2. in order to set to DC scale and measure the voltage between the harness connector terminals 11 and 13, use a J 39200 DMM .

Is the voltage greater than the specified value?

2V

Go to Step 16

Go to Step 19

13

Inspect the state of the battery.

Is the battery charged enough to power the cellular telephone?

--

Go to Step 18

Go to Step 17

14

Inspect for intermittents, poor connections, or a loose ground G400.

Is the repair complete?

--

Go to Cellular Telephone System Check

--

15

Repair the open in CKT 1051 (BLK).

Is the repair complete?

--

Go to Cellular Telephone System Check

--

16

Repair the short to voltage in CKT 679 (PPL).

Is the repair complete?

--

Go to Cellular Telephone System Check

--

17
  1. Disconnect the cellular telephone handset interface connector from the vehicle harness connector.
  2. In order to set to DC scale and inspect for battery voltage at the harness connector terminal 12, use a J 39200 DMM.

Is battery voltage present?

B+

Go to Step 29

Go to Step 28

18

Replace the handset.

Is the repair complete?

--

Go to Cellular Telephone System Check

--

19
  1. Turn the ignition to the OFF position.
  2. in order to set to OHMS scale and inspect the continuity between the cellular telephone module harness connector terminal Y and the cellular telephone handset interface harness connector terminal 11, use a J 39200 DMM.

Is continuity present?

--

Go to Step 21

Go to Step 20

20

Repair the open in CKT 679 (PPL).

Is the repair complete?

--

Go to Cellular Telephone System Check

--

21
  1. Turn the ignition to the RUN position.
  2. in order to set to DC scale and measure the voltage between the cellular telephone module connector terminals A and D, use a J 39200 DMM.

Is battery voltage present?

B+

Go to Step 23

Go to Step 22

22

in order to set to OHMS scale and inspect for continuity between the cellular telephone module terminal Z and the cellular telephone handset interface harness connector  terminal 10, use a J 39200 DMM.

Is continuity present?

--

Go to Step 24

Go to Step 25

23

Repair the short to ground in CKT 1266 (RED).

Is the repair complete?

--

Go to Cellular Telephone System Check

--

24

Replace the handset cord with a known good cord.

Does the cellular telephone power up?

--

Go to Cellular Telephone System Check

Go to Step 26

25

Repair the open in CKT 1798 (GRY/BLK).

Is the repair complete?

--

Go to Cellular Telephone System Check

--

26

Replace the handset with a known good handset.

Does the cellular telephone power up?

--

Go to Cellular Telephone System Check

Go to Step 27

27

Replace the handset with a known good handset.

Is the repair complete?

--

Go to Cellular Telephone System Check

--

28
  1. Inspect for an open in CKT 41 (ORN).
  2. If OK, replace the cellular telephone module.

Is the repair complete?

--

Go to Cellular Telephone System Check

--

29

Use a J 39200 DMM in order to inspect for battery voltage between the cellular telephone handset interface harness connector terminals 12 and 13.

Is battery voltage present?

B+

Go to Step 30

Go to Step 31

30
  1. Inspect the harness connector and the cellular telephone handset interface jumper for proper terminal contact.
  2. If the harness connector is OK, perform a continuity check on the cellular telephone handset interface jumper.
  3. If the cellular telephone handset interface jumper is OK, replace the cellular telephone handset interface.

Is the repair complete?

--

Go to Cellular Telephone System Check

--

31

Repair the open ground CKT 1051 (BLK).

Is the repair complete?

--

Go to Cellular Telephone System Check

--