GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The instrument panel cluster (IPC) monitors the battery positive voltage and battery negative circuit voltage to determine if it is between 9-15 volts.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1327 Device Power Circuit Low

Conditions for Running the DTC

This DTC shall run only if the IPC has power, ground, and the ignition is not in START mode.

Conditions for Setting the DTC

This DTC shall be set as current when the voltage falls below 9 volts for 0.5 seconds.

Action Taken When the DTC Sets

    • The odometer and the PRNDL displays do not illuminate.
    • The fuel gage and the engine coolant temperature gage default to 0.
    • The scan tool does not communicate with the instrument cluster.

Conditions for Clearing the DTC

    • The DTC becomes history when the conditions for setting the DTC are no longer present.
    • The history DTC clears after 100 malfunction free warm-up cycles.
    • The IPC receives the clear code command from the scan tool.

Diagnostic Aids

    • When the instrument cluster detects low voltage at the battery positive voltage circuit, the instrument cluster will not communicate with the scan tool, and the odometer and PRNDL displays will not be illuminated. The season odometer will display if the trip reset switch is pressed, and the instrument cluster will communicate with the scan tool until the trip reset switch is released.
    •  An intermittent condition is likely to be caused by an open condition in the battery positive voltage circuit.
    • DTC B1327 can only be read by the scan tool as a history code once the fault is removed. Refer to Scan Tool Does Not Communicate with Class 2 Device for diagnosis of a loss of communication with the instrument cluster.

Step

Action

Yes

No

Schematic Reference: Instrument Cluster Schematics

Connector End View Reference: Data Communication Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Test the battery positive voltage circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 6

Go to Step 3

3

Test the ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 6

Go to Step 4

4

Inspect for poor connections at the harness connector of the instrument panel cluster (IPC). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 6

Go to Step 5

5

Replace the IPC. Refer to Control Module References for replacement, setup, and programming .

Did you complete the replacement?

Go to Step 6

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6

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2