Chevrolet Silverado / GMC Sierra. Service manual — part 2421

Circuit/System Description

The driver information switches are normally open momentary switches. Power is provided to the
driver information center (DIC) switches via the instrument panel cluster (IPC). The IPC
interfaces with the DIC switches via 3 discreet circuits. The switch input to the cluster is pulled
low or grounded when a switch is activated. The IPC reads the voltage at the analog input to
determine which switches is pressed. The switch input to the cluster is set up in a resistor ladder
format for three of the four switches. The DIC switches include the PERSONALIZATION,
SET/RESET, TRIP/FUEL, AND VEHICLE INFO switches. A stuck switch or a short to battery
sets a DTC.

Conditions for Running the DTC

The ignition is in ACCESSORY or RUN.

Conditions for Setting the DTC

The IPC detects that the DIC switch is stuck.

The IPC detects that the DIC switch signal circuit is shorted to battery.

Action Taken When the DTC Sets

The IPC ignores the DIC switch inputs.

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 40 malfunction-free warm-up cycles.

The engine control module (ECM) receives a clear code command from the scan tool.

Diagnostic Aids

When the DIC switches are stuck, only the TRIP/FUEL switch functions correctly. When
the TRIP/FUEL switch is stuck, all other DIC switches function correctly.

Only the DIC signal circuit can be diagnosed as shorted to battery.

Reference Information

Circuit

Short to

Ground

Open/High

Resistance

Short to

Voltage

Signal

Performance

DIC Switch Signal

1

1

B3567 01

B3567 59

1. Driver Information Center (DIC) Switch Inoperative

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Displays and Gages - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Driver Information Center (DIC) Description and Operation

Instrument Cluster Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the DIC switch assembly.

2. Ignition OFF, test for less than 1 ohm between the low reference terminal 2 and ground.

If greater than the specified range, test the low reference circuit for an open/high
resistance.

3. Ignition OFF, test for less than 1 ohm between the ground terminal 5 and ground.

If greater than the specified range, test the ground circuit for an open/high resistance.

4. Ignition ON, verify that all of the scan tool DIC Switch parameters are Inactive.

If any are not Inactive, test the appropriate signal circuit terminal 1 or terminal 3 for a
short to ground. If the circuit tests normal, replace the IPC.

5. Ignition ON, install a 3-amp fused jumper wire between the signal circuit terminal 1 and the

low reference circuit terminal 2. Verify the scan tool DIC Switch parameters, except the
DIC Fuel Info. parameter, are Active.

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Displays and Gages - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

If any are not Active, test the signal circuit for a short to voltage or an open/high
resistance. If the circuit tests normal, replace the IPC.

6. Ignition ON, install a 3-amp fused jumper wire between the signal circuit terminal 3 and

ground. Verify the scan tool DIC Fuel Info. parameter is Active.

If not Active, test the signal circuit for a short to voltage or and open/high resistance. If
the circuit tests normal, replace the IPC.

7. If all the circuits test normal, test or replace the DIC switch assembly.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Steering Wheel Control Switch Assembly Replacement

Control Module References for the IPC replacement, setup, and programming

DTC P0381

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0381

Wait To Start Lamp Control Circuit

Diagnostic Fault Information

Circuit/System Description

Ignition voltage is supplied directly to the wait to start indicator. The engine control module
(ECM) controls the lamp by grounding the control circuit via an internal switch called a driver.
The primary function of the driver is to supply the ground for the component being controlled.
Each driver has a fault line which is monitored by the ECM. When the ECM is commanding a

Circuit

Short to

Ground

Open/High

Resistance

Short to

Voltage

Signal

Performance

Wait To Start Signal

P0381

P0381

P0381

-

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Displays and Gages - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

component ON, the voltage of the control circuit should be low, near zero volts. When the ECM
is commanding the control circuit to a component OFF, the voltage potential of the circuit should
be high, near battery voltage. If the fault detection circuit senses a voltage other than what is
expected, the fault line status will change causing the DTC to set.

Conditions for Running the DTC

The ignition voltage is greater than 6 volts but less than 18 volts.

Conditions for Setting the DTC

The ECM detects that the commanded state of the driver and the actual state of the control
circuit do not match.

The condition must be present for a minimum of 5 seconds.

Action Taken When the DTC Sets

The ECM stores the DTC information in memory.

The ECM records the operating conditions at the time the DTC sets. The ECM displays the
failure information in the Failure Records on the scan tool.

Conditions for Clearing the DTC

The history DTC clears after 40 malfunction-free warm-up cycles.

The DTC becomes history when the conditions for setting the DTC are no longer present.

The ECM receives the clear code command from the scan tool.

Diagnostic Aids

Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate
the DTC, the information in the Failure Records can help determine how many miles since the
DTC set. The Fail Counter and Pass Counter can help determine how many ignition cycles that
the diagnostic test reported a pass and/or a fail.

The wait to start indicator illuminates only with the ignition ON and the engine OFF. The wait to
start indicator will not illuminate during post-start glow plug operation. The wait to start
indicator will not stay ON for long at higher engine temperatures.

Reference Information

Schematic Reference

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Displays and Gages - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado