Before testing separate components or systems, perform all procedures listed in BASIC TESTING article in the ENGINE PERFORMANCE section. Since many computer-controlled and monitored components will set a diagnostic trouble code if they malfunction, it is also recommended that self-diagnosis be performed. See appropriate TESTS W/CODES - 5.7L article in the ENGINE PERFORMANCE section.

NOTE: Testing individual components does not isolate shorts or opens. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens. The following table provides the location of commonly used diagnostic information. These former "A" and "C" charts are now written in text and inserted into the appropriate location in the new Engine Performance workflow. To familiarize yourself with the Engine Performance workflow, see AA - HOW TO USE THE ENGINE PERFORMANCE SECTION article in GENERAL INFORMATION section.

GENERAL MOTORS A & C CHART REFERENCE

System Or Component

Diagnostic Information Location

A-1 & A-2, MALFUNCTION INDICATOR LIGHT (MIL)

⁽¹⁾ See DIAGNOSTIC CIRCUIT CHECK

A-3, No Start

⁽¹⁾ See NO START - ENGINE CRANKS OKAY

A-5, Fuel Pump Relay

See FUEL SYSTEM in this article

A-7, Fuel System Diagnosis

⁽¹⁾ See BASIC FUEL SYSTEM CHECKS

C-1, ECM/PCM Replacement Check

⁽¹⁾ See ECM/PCM REPLACEMENT CHECK

C-1, MAP Sensor

See ENGINE SENSORS & SWITCHES in this article

C-1, Power Steering Pressure Switch

See ENGINE SENSORS & SWITCHES in this article

C-1, Park/Neutral Position Switch

See ENGINE SENSORS & SWITCHES in this article

C-2, Injector Balance Test

See FUEL SYSTEM in this article

C-2, Injector Coil Test

See FUEL SYSTEM in this article

C-2, Injector Leak Test

See FUEL SYSTEM in this article

C-2, IAC Motor

See IDLE CONTROL SYSTEM in this article

C-2, ISC Motor

See IDLE CONTROL SYSTEM in this article

C-3, Canister Purge System (Fuel Evaporation Control)

See EMISSION SYSTEMS & SUB-SYSTEMS in this article

C-4, EST Ignition Check

See BASIC IGNITION SYSTEM CHECKS in this article

C-5, KS Ignition Check

See IGNITION SYSTEM in this article

C-6, Air Injection System

See EMISSION SYSTEMS & SUB-SYSTEMS in this article

C-7, EGR System

See EMISSION SYSTEMS & SUB-SYSTEMS in this article

C-8, Manual Transmission Shift Lights (Transmission)

See MISCELLANEOUS CONTROLS in this article

C-8, Torque Converter Clutch (Transmission)

⁽²⁾ See MISCELLANEOUS CONTROLS in this article

C-10, A/C Clutch Control

See MISCELLANEOUS CONTROLS in this article

C-12, Electric Cooling Fan Control

See MISCELLANEOUS CONTROLS in this article

C-16, Engine Coolant Level Switch

See ENGINE SENSORS & SWITCHES in this article

C-16, Fuel Pump/Oil Pressure Switch

See ENGINE SENSORS & SWITCHES in this article

C-16, Oil Level Switch

See ENGINE SENSORS & SWITCHES in this article

C-18, Supercharger Boost Control

See AIR INDUCTION SYSTEMS in this article

⁽¹⁾	See BASIC TESTING article in the ENGINE PERFORMANCE section.

⁽²⁾	Covered in entirety in appropriate TRANSMISSION SERVICING & REPAIR manual.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Engine Controls - System/Component Tests - 5.7L: Introduction

Use the Manual With the Right Hardware

When to See a Mechanic

Rather have a pro handle this?