GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the Data Link Connector (DLC) Diagnostic System Check performed?

--

Go to Step 2

Go to Data Link Communications System Check

2

  1. Turn the ignition switch on.
  2. Attempt to turn on the radio.

Does the radio turn on?

--

Go to Step 3

Go to Step 10

3

Is the scan tool properly configured to interface with this vehicle?

--

Go to Step 4

Go to Step 11

4

  1. Connect scan tool on a known good vehicle.
  2. Perform the DLC Diagnostic System Check on known good vehicle. Refer to Data Link Communications System Check in Wiring Systems.

Does the scan tool communicate with the known good vehicle?

--

Go to Step 5

Go to Step 11

5

  1. Turn the ignition switch off.
  2. Disconnect the radio electrical connector.
  3. Disconnect the CD player electrical connector (if equipped with RPO U1S).
  4. Using a DMM, measure the resistance between the DLC terminal 14 and ground.

Is the resistance within the specified range?

Go to Step 6

Go to Step 12

6

  1. Turn the ignition switch on.
  2. Using a DMM, measure the voltage between the DLC terminal 14 and ground.

Is the voltage within the specified range?

Less than 2V

Go to Step 7

Go to Step 13

7

  1. If vehicle is not equipped with remote CD player, skip to Step 8 .
  2. Using a DMM, measure the resistance between the DLC terminal 14 and the CD player harness connector terminal 10.

Is the resistance within the specified range?

Less than 2ohms

Go to Step 8

Go to Step 14

8

Using a DMM, measure the resistance between the DLC terminal 14 and the radio harness connector terminal E1.

Is the resistance within the specified range?

Less than 2ohms

Go to Step 9

Go to Step 14

9

  1. Turn the ignition switch off.
  2. Reconnect the radio electrical connector.
  3. Reconnect the CD player electrical connector (if equipped with RPO U1S).
  4. Reconnect scan tool to DLC.
  5. Turn the ignition switch on.
  6. Using scan tool, attempt to communicate with radio.
  7. Using scan tool, attempt to communicate with the CD player (if equipped with RPO U1S).

Does scan tool communicate with the radio and the CD player?

--

Go to Step 15

Go to Step 10

10

Refer to Diagnostic System Check - Radio/Audio System in Entertainment for further diagnosis and repair of the vehicle's audio system.

Is the action complete?

--

Go to Step 16

--

11

Refer to the scan tool manufacturer and/or scan tool user's manual for correct operation of the scan tool.

Is the action complete?

--

Go to Step 16

--

12

Repair short to ground in circuit 835.

Is the repair complete?

--

Go to Step 16

--

13

Repair short to B+ in circuit 835.

Is the repair complete?

--

Go to Step 16

--

14

Repair poor connection or open in circuit 835.

Is the repair complete?

--

Go to Step 16

--

15

Malfunction is not present at this time. Check the connection between the scan tool and the DLC for poor terminal contact.

Is the action complete?

--

Go to Step 16

--

16

  1. Turn the ignition switch off.
  2. Reinstall connectors/components removed.

Is the action complete?

--

Go to Data Link Communications System Check

--