GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1998 🢒 DeVille 🢒 Body and Accessories 🢒 Entertainment 🢒 Cellular Telephone - Noisy Audio During Hands-Free

Step

Action

Value(s)

Yes

No

1

Is the audio noisy from the vehicle sound system?

--

Go to Step 3

Go to Step 2

2

Is the audio noisy from the handset earpiece?

--

Go to Step 4

--

3

Is the audio noisy when the radio is on?

--

Go to Step 6

Go to Step 5

4
  1. Turn the ignition to the OFF position.
  2. Disconnect the cellular telephone module connector and the harness connector from the cellular telephone handset interface.
  3. Turn the ignition to the RUN position.
  4. Use a J 39200 digital multimeter (DMM) set to DC scale in order to measure the voltage between the cellular telephone module connector terminals V and A and then between terminals P and A.

Is battery voltage present in either test?

B+

Go to Step 8

Go to Step 7

5
  1. Turn the ignition to the OFF position.
  2. Disconnect the cellular telephone module connector and the harness connector from the cellular telephone handset interface.
  3. Turn the ignition to the RUN position.
  4. Use a J 39200 DMM set to DC scale in order to measure the voltage between the cellular telephone module connector terminals G and A.

Is battery voltage present?

B+

Go to Step 10

Go to Step 9

6

Refer to Audio Preliminary Diagnosis for Diagnosis.

Is the repair complete?

--

Go to Cellular Telephone System Check

--

7

Use the J 39200 DMM in set to OHMS scale in order to test for continuity between the cellular telephone module connector  terminal V and the harness shield then terminal P and the harness shield.

Is continuity present?

--

Go to Step 11

Go to Step 12

8

Repair the short to battery in CKT 814. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Cellular Telephone System Check

--

9

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

Is battery voltage present?

--

Go to Step 14

Go to Step 13

10

Repair the short to the battery in CKT 814. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Cellular Telephone System Check

--

11

Use the J 39200 DMM in order to inspect for continuity between the cellular telephone module connector terminal N and the cellular telephone handset interface harness connector terminal 3.

Is continuity present?

--

Go to Step 15

Go to Step 16

12

Repair the open in CKT 814. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Cellular Telephone System Check

--

13
  1. Inspect all of the connectors for proper terminal contact.
  2. If the contact is OK, replace the cellular telephone module.

Is the repair complete?

--

Go to Cellular Telephone System Check

--

14

Repair the short to the battery in CKT 659 (LT BLU/BLK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Cellular Telephone System Check

--

15

Replace the handset cord with a known good cord.

Is the audio still noisy?

--

Go to Step 17

Go to Cellular Telephone System Check

16

Repair the open in CKT 1235 (LT BLU/BLK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Cellular Telephone System Check

--

17

Replace the handset with a known good handset.

Is the audio still noisy?

--

Go to Step 18

Go to Cellular Telephone System Check

18
  1. Inspect all of the connectors for proper terminal contact.
  2. If the contact is OK, replace the cellular telephone module.

Is the repair complete?

--

Go to Cellular Telephone System Check

--