DTC B1428. Chevrolet Caprice WM 2009

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2009 🢒 Caprice WM 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC B1428

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 B1428 00: Ignition Switched Power Relay 1 Circuit

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Ignition Relay Coil B+	B1380 06, B1428 00, U0100-U0299, 1, 2	P0628 00, 1, 3, 4	B1440 00, 5	--
Ignition Relay Switch B+	1, 2, 3, 4	1, 2, 3, 4	--	--
Ignition Relay Control	1, 2, 3, 4	1, 2, 3, 4	--	--
Ignition Relay Ground	--	1, 2, 3, 4	--	--
Some modules may lose communication and/or be inoperable. The B+ circuit fuse to the ignition switch may be open. SIR system may retain DTC B1370 06 as current. Vehicle may not start. Vehicle will continue to run after the ignition key is removed.

The body control module (BCM) controls the R14 IGN relay through the run/crank ignition circuit by applying voltage to the circuit. The R14 IGN relay is energized when the ignition switch is in the RUN or CRANK position, or when a remote start is requested.

Conditions for Running the DTC

•	The system voltage is between 9-16 V.

•	The ignition 1 relay control output is active.

Conditions for Setting the DTC

The BCM detects a short to ground on the ignition circuit.

Action Taken When the DTC Sets

The BCM disables the ignition output driver.

Conditions for Clearing the DTC

•	The condition responsible for setting the DTC no longer exists.

•	A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Reference Information

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

Ignition OFF, disconnect the R14 IGN relay.
Test for less than 10 Ω between the ground circuit terminal 86 and ground.

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

Connect a test lamp between the B+ circuit terminal 85 and the ground circuit terminal 86.
Command the Run/Crank Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the B+ circuit for a short to voltage. If the circuit tests normal, replace the BCM.

⇒	If the test lamp is always OFF, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

If all circuits test normal, test or replace the R14 IGN relay.

Component Testing

Ignition OFF, disconnect the R14 IGN relay.
Test for 60 - 180 Ω between the B+ terminal 85 and the ground terminal 86 of the R14 IGN relay.

⇒	If not within the specified range, replace the relay.

Test for infinite resistance between the following terminals:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If not the specified value, replace the relay.

Install a 3 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 Ω between terminals 30 and 87.

⇒	If greater than specified range, replace the relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM replacement, setup, and programming