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For 1990-2009 cars only
Makes 🢒 Buick 🢒 1999 🢒 Regal (China) (CNG) 🢒 DTC 🢒 DTC B0602 PLL Oscillator Error

Circuit Description

The oscillator is a device used in the instrument cluster in order to send and interpret data between the other components along the class 2 serial data line. The oscillator's major function is to send or receive the different binary (bytes) information between the instrument and the other components within the vehicle. When the ignition switch is first turned on , the instrument cluster performs an internal test on the oscillator. This test may determine the integrity of the instrument cluster's operation.

Conditions for Setting the DTC
    • The instrument cluster is unsuccessful at verifying the oscillator's operation.
    • The oscillator is being disrupted by an outside radio frequency interference.
    • The conditions may occur at any time.

Action Taken When the DTC Sets
    • The system stores a DTC B0602 in the instrument cluster memory.
    • The SERVICE VEHICLE SOON displays for this DTC.

Conditions for Clearing the MIL/DTC
    • Under all the fault conditions, cycle the ignition before this DTC may change from current to history.
    • A history DTC will clear after 100 drive cycles if the condition for the malfunction is no longer present.
    • Use a scan tool.

Diagnostic Aids

The oscillator is not removable from the instrument cluster and DTC B0602 is an internal malfunction to the instrument cluster. There is no repair procedure for this malfunction. Replace the instrument cluster. Refer to Instrument Cluster Replacement .

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. Always perform the Instrument Cluster Diagnostic system Check before attempting diagnosis of a DTC B0602.

    2.

  2. This test may determine if there is a short to B+ in CKT 1500.

    3.

  3. This test inspects for an open in CKT 1500.

    4.

  4. This test may determine if there is a short to B+ in CKT 806.

    5.

  5. This test inspects for an open in CKT 806.

    6.

  6. This test may determine if there is a short to B+ in CKT 39

    7.

  7. This test inspects for an open in CKT 439.

Step

Action

Value(s)

Yes

No

1

Did you perform the Instrument Cluster Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

2

  1. Disconnect the instrument cluster connector.
  2. Turn the ignition switch to the ACCESSORY position.
  3. Use a test light in order to backprobe between the instrument cluster harness connector terminal A8 (CKT 1500) and ground.

Does the test lamp light?

--

Go to Step 3

Go to Step 4

3
  1. Repair a short to B+ in CKT 1500.
  2. Inspect the system.

Is the repair complete?

--

Go to Step 15

--

4

  1. Turn the ignition switch to the RUN position.
  2. Leave the test light at the same location.

Does the test lamp light?

--

Go to Step 5

Go to Step 6

5

  1. Turn the ignition switch to the OFF position.
  2. Use a test light in order to backprobe between the instrument cluster harness connector terminal A3 (CKT 806) and ground.

Does the test lamp light?

--

Go to Step 7

Go to Step 8

6
  1. Repair the following conditions in CKT 1500 between the instrument cluster harness terminal A8 and the fuse block terminal A8:
    2. • A poor connection
    • An open
  2. Inspect the system.

Is the repair complete?

--

Go to Step 15

--

7
  1. Repair a short to B+ in CKT 806.
  2. Inspect the system.

Is the repair complete?

--

Go to Step 15

--

8

  1. Turn the ignition switch to the START position.
  2. Leave the test light at the same location.

Does the test lamp light?

--

Go to Step 9

Go to Step 10

9

  1. Turn the ignition switch to the OFF position.
  2. Use a test light in order to backprobe between the instrument cluster harness connector terminal B12 and ground.

Does the test lamp light?

--

Go to Step 12

Go to Step 11

10
  1. Repair the following conditions in CKT 806 between the instrument cluster harness terminal A3 and the fuse block terminal A4:
    2. • A poor connection
    • An open
  2. Inspect the system.

Is the repair complete?

--

Go to Step 15

--

1 1

  1. Turn the ignition switch to the RUN position.
  2. Leave the test light at the same location.

Does the test lamp light?

--

Go to Step 13

Go to Step 14

12
  1. Repair a short to B+ in CKT 39.
  2. Inspect the system.

Is the repair complete?

--

Go to Step 15

Go to Step 13

13
  1. Replace the instrument cluster. Refer to Instrument Cluster Replacement .
  2. Inspect the system.

Is the repair complete?

--

Go to Step 15

--

14
  1. Repair the following conditions in CKT 39 between the fuse block terminal D6 and the instrument cluster harness terminal B12:
    2. • A poor connection
    • An open
  2. Inspect the system.

Is the repair complete?

--

Go to Step 15

--

15
  1. Turn the ignition switch to the OFF position.
  2. Connect/install any connectors/components that were disconnected or removed.
  3. Clear all of the DTCs. Refer to Clearing DTCs .

Are all DTCs cleared?

--

System OK

--