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For 1990-2009 cars only
Makes 🢒 Buick 🢒 2000 🢒 Century (China) 🢒 Engine 🢒 Engine Controls - 2.5L (LB8) and 3.0L (L46) 🢒 DTC B0608 Power Moding Error

Object Number: 501866 Size: MF
Body Control Module Components
Body Control System Schematics

Circuit Description

The BCM receives three voltage inputs. The BCM receives voltage from the (10A fuse that is in cavities A7 and A8 of the fuse block) circuit at all times except when the ignition switch is off. The BCM receives voltage from the (10A fuse that is in cavities D9 and D10 of the fuse block) circuit when the ignition switch is in the ON or START position. The BCM receives voltage from the (10A fuse that is in cavities A3 and A4 of the fuse block) crank circuit when the ignition switch is in the start position.

Conditions for Setting the DTC

The BCM sets DTC B0608 when detecting any of these conditions for more than 0.3 seconds:

    • Voltage in IGN 1 circuit is greater than 8 volts, and voltage in the IGN 0 circuit is less than 1.5 volts.
    • Voltage in the crank circuit is greater than 4.5 volts, and the voltage in the IGN 0 circuit is less than 1.5 volts.
    • Voltage in the crank circuit is greater than 4.5 volts, and the voltage in the IGN 1 circuit is less than 1.5 volts.

Action Taken When the DTC Sets

the BCM stores DTC B0608 in memory.

Conditions for Clearing the DTC
    • The BCM no longer detects an open or short to B+ in the IGN 1circuit, the IGN 0 circuit, or the CRANK circuit.
    • A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
    • Using a scan tool.

Diagnostic Aids
    • If the DTC B0608 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • The following conditions may cause an intermittent malfunction to occur:
      • An intermittent open or short to B+ in the IGN 1 circuit, the IGN 0 circuit, or the CRANK circuit.
      • Poor connections at the BCM, or the fuse block.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests for a short to ground in the crank circuit.

    2.

  2. This step tests for a short to ground in the IGN 0 circuit.

    3.

  3. This step tests for a short to B+ in the IGN 0 circuit.

    4.

  4. This step tests for an open in the IGN 1 circuit.

    5.

  5. This step tests for a short to B+ in the crank circuit.

    6.

  6. This step tests for an open in the crank circuit.

    7.

  7. This step tests for a short to B+ in the IGN 0 circuit.

    8.

  8. This test tests for an open in the IGN 0 circuit.

    9.

  9. This test determines whether the malfunction is intermittent or whether the BCM is faulty.

Step

Action

Value(s)

Yes

No

1

Was the BCM Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - Body Control System

2

Check the 10A fuse in cavities A3 and A4 of the fuse block.

Is the 10A fuse in cavities A3 and A4 of the fuse block open?

--

Go to Step 3

Go to Step 4

3
  1. Turn the ignition switch to the OFF position.
  2. Replace the 10A fuse in cavities A3 and A4 of the fuse block.
  3. Turn the ignition switch to the START position momentarily.

    4. IMPORTANT: The engine may start.

  4. Check the 10A fuse in cavities A3 and A4 of the fuse block again.

Is the 10A fuse in cavities A3 and A4 of the fuse block open again?

--

Go to Step 13

Go to Step 4

4

Check the 10A fuse in cavities A7 and A8 of the fuse block.

Is the 10A fuse in cavities A7 and A8 of the fuse block open?

--

Go to Step 5

Go to Step 6

5
  1. Turn the ignition switch to the OFF position.
  2. Replace the 10A fuse in cavities A7 and A8 of the fuse block.
  3. Turn the ignition switch to the RUN position.
  4. Check the 10A fuse in cavities A7 and A8 of the fuse block again.

Is the 10A fuse in cavities A7 and A8 of the fuse block open again?

--

Go to Step 14

Go to Step 6

6

  1. Turn the ignition switch to the RUN position.
  2. Using a test light, backprobe between the BCM IGN 1 circuit input and ground.

Does the test light stay off?

--

Go to Step 7

Go to Step 15

7
  1. Leave the test light connected from the previous step.

    2. Important: The engine may start.

  2. While observing the test light, turn the ignition switch to the RUN position, then to the START position.
  3. Turn the ignition switch to the OFF position.

Was the test light on with the ignition switch in the RUN and START position?

--

Go to Step 8

Go to Step 16

8

  1. Using a test lamp, backprobe between the BCM crank circuit input and ground.
  2. While observing the test lamp, turn the ignition switch from the OFF position to the RUN position.

Did the test lamp stay off when turning the ignition switch from the OFF position to the RUN position?

--

Go to Step 9

Go to Step 17

9

  1. Leave the test lamp connected from the previous step.

    2. Important: The engine may start.

  2. Turn the ignition switch to the START position momentarily.
  3. Turn the ignition switch to the OFF position.

Did the test lamp turn on when turning the ignition switch to the START position?

--

Go to Step 10

Go to Step 18

10

  1. Make sure the ignition switch is in the OFF position.
  2. Using a test light, connect by backprobing between the BCM IGN 1 input circuit and ground.

Does the test lamp stay off?

--

Go to Step 11

Go to Step 19

11

  1. Leave the test light connected from the previous step.

    2. Important: The engine may start.

  2. While observing the test lamp. turn the ignition switch to ACC, then to RUN, then to START.

Did the test light turn on with the ignition switch in the ACC, RUN or START position?

--

Go to Step 12

Go to Step 20

12

  1. Turn the ignition switch to the ON position.
  2. Clear the BCM DTCs.
  3. Turn the ignition switch to the OFF position.
  4. Wait 10 seconds.
  5. Turn the ignition switch to the ON position.
  6. Check for BCM DTCs.

Does DTC B0608 reset as a current DTC?

--

Go to Step 21

Go to Step 22

13

Repair short to ground in the crank circuit.

Is the repair complete?

--

Go to Step 23

--

14

Repair short to ground in the IGN 0 circuit.

Is the repair complete?

--

Go to Step 23

--

15

Repair short to voltage in the IGN 1 circuit.

Is the repair complete?

--

Go to Step 23

--

16

Repair poor connection or open in the IGN 1 circuit.

Is the repair complete

--

Go to Step 23

--

17

Repair short to voltage in the crank circuit or a faulty ignition switch.

Is the repair complete?

--

Go to Step 23

--

18

Repair poor connection or open in the crank circuit.

Is the repair complete?

--

Go to Step 23

--

19

Repair short to voltage in the IGN 0 circuit or a faulty ignition switch.

Is the repair complete?

--

Go to Step 23

--

20

Repair poor connection or open in the IGN 0 circuit.

Is the repair complete?

--

Go to Step 23

--

21
  1. Test the BCM connector C1 for poor connections. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. If the connectors are OK, then replace the BCM. Refer to Body Control Module Replacement for more information.
  3. After replacing the BCM, perform the Setup new BCM procedure. Refer to Body Control Module (BCM) Programming/RPO Configuration for more information.

Is the repair complete?

--

Go to Step 23

--

22

The malfunction is not present at this time. Refer to Diagnostic Aids for additional information regarding this DTC.

Is the action complete?

--

Go to Step 23

--

23
  1. Turn the ignition switch to the OFF position.
  2. Reinstall connectors/components removed.
  3. Turn the ignition switch to the RUN position.
  4. Clear the BCM DTCs.
  5. Check for BCM DTCs.

Are there any current BCM DTCs set?

--

Go to Diagnostic System Check - Body Control System

System OK