Chevrolet Silverado / GMC Sierra. Service manual — part 669

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

The following conditions exist for at least 10 seconds.

B1370 01

The SDM detects a short to battery in the ignition 1 voltage circuit when the switch is in the OFF
position.

B1370 06

The SDM detects a short to ground or an open in the ignition 1 voltage circuit when the ignition
switch is in RUN or CRANK.

Action Taken When the DTC Sets

The SDM commands the AIR BAG indicator ON.

The SDM determines its power mode only from the GMLAN power mode messages and
discards the ignition 1 input for the remainder of the ignition cycle.

Conditions for Clearing the DTC

The condition for setting the DTC no longer exists.

A history DTC will clear once 100 malfunction-free ignition cycles have occurred.

Diagnostic Aids

A history DTC maybe caused by an intermittent short or open in the ignition 1 circuit.

Reference Information

Schematic Reference

SIR Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

2008 Chevrolet Silverado 1500

2008 RESTRAINTS Supplemental Inflatable Restraints - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

SIR System 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

Circuit/System Testing

1. Ignition OFF, remove the underhood AIR BAG IGN fuse 39.

2. Ignition ON, test for 9-16 V between the voltage supply side and ground.

If not within the specified range, refer to DTC B1370 .

3. Ignition OFF, remove the SDM harness connector.

4. Ignition OFF, test for less then 1 ohm between the ignition 1 voltage circuit terminal 32 and

the underhood fuse block terminal G2 (X5).

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

5. Ignition ON, test for less then 1 volt between the SDM harness connector ignition 1 voltage

circuit terminal 32 and the underhood fuse block terminal G2 (X5).

If greater then the specified value, test the circuit for a short to voltage.

6. If all circuits test normal, reconnect all connectors, replace fuse, clear all DTCs. If DTC

B1370 stays current, replace the SDM.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

IMPORTANT: When removing connectors inspect for damage or corrosion.

Damage or corrosion in the following requires repair or
replacement of the affected.

SDM

SDM wiring harness

2008 Chevrolet Silverado 1500

2008 RESTRAINTS Supplemental Inflatable Restraints - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

SIR/SRS Wiring Repairs

Control Module References for SDM replacement, setup, and programming

PASSENGER PRESENCE SYSTEM REZEROING

Introduction

The Inflatable Restraints Passenger Presence System (PPS) is a calibrated system that requires
rezeroing anytime the seat cushion trim attachments have been removed or the PPS has been
replaced. The procedures below are designed to assist in the rezeroing of the PPS. Before you
start, read these procedures carefully and completely. For further information regarding the PPS
refer to SIR System Description and Operation.

1. Read this procedure carefully and completely.

2. The PPS will not function properly if the PPS rezeroing procedure is not performed.

3. Perform the Diagnostic System Check - Vehicle after successfully completing the

rezeroing procedure to ensure the system is functioning properly.

Passenger Presence System (PPS) Rezeroing Procedure

1. Empty the front outboard passenger seat.

2. Verify that all SIR and PPS components, connectors, and connector position assurances

(CPAs) are properly connected and mounted.

3. Install a scan tool.

4. Turn ON the ignition, with the engine OFF.

IMPORTANT: The following procedures must be followed:

IMPORTANT: Before rezeroing the PPS, the front passenger seat must be

completely empty of all items. The presence of any items on the
front passenger seat will affect the calibration and operation of
the PPS.

IMPORTANT: DTC B0081 4B may be set prior to rezeroing the system if the

system was replaced with a service kit. All other SIR and PPS
DTCs must be cleared before rezeroing the PPS. The
presence of current or history DTCs will prevent the PPS
from rezeroing and may set additional DTCs.

2008 Chevrolet Silverado 1500

2008 RESTRAINTS Supplemental Inflatable Restraints - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado

5. Use the scan tool in order to clear the SIR and PPS DTCs.

6. With a scan tool, request the PPS rezeroing procedure.

7. Initiate the PPS rezeroing procedure. The PPS will illuminate both PASSENGER AIR

BAG ON and OFF indicators until the rezeroing procedure has been completed.

8. When the rezeroing procedure has been successfully completed, the PPS will display the

current system status.

9. If the rezeroing procedure was unsuccessful, repeat this procedure. Due to the

communication status between the SDM and the PPS module, this procedure may have to be
repeated until a successful rezero attempt has been achieved.

10. After the PPS has been successfully rezeroed, perform the Diagnostic System Check -

Vehicle .

SYMPTOMS - SIR

Visual/Physical Inspection

Inspect for aftermarket devices which could affect the operation of the SIR system. Refer to
Checking Aftermarket Accessories .

Inspect the easily accessible or visible system components for obvious damage or conditions
which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to
Testing for Intermittent Conditions and Poor Connections .

IMPORTANT: The following steps must be completed before using the

Symptom Tables.

1. Perform the Diagnostic System Check - Vehicle , before

using the Symptom Tables in order to verify that all of the
following are true:

There are no DTCs set.

The control module(s) can communicate via the serial
data link.

2. Review the system operation in order to familiarize yourself

with the system functions. Refer to SIR System Description
and Operation.

2008 Chevrolet Silverado 1500

2008 RESTRAINTS Supplemental Inflatable Restraints - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra &

Silverado