Engine Controls - System/Component Tests: Introduction
Before testing separate components or systems, perform procedures in BASIC TESTING article in this section. Since many computer-controlled and monitored components set a trouble code if they malfunction, also perform procedures in appropriate TESTS W/CODES article in this 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 and refer to WIRING DIAGRAMS
to isolate wiring harness shorts or opens.
IMPORTANT: 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 HOW TO USE THE ENGINE PERFORMANCE SECTION in GENERAL INFORMATION.
GENERAL MOTORS "A" & "C" CHART REFERENCE
| System or Component | Diagnostic Information Location | ||
|---|---|---|---|
| DIAGNOSTIC CIRCUIT CHECK | See DIAGNOSTIC CIRCUIT CHECK in BASIC DIAGNOSTIC PROCEDURES | ||
| A-1 & A-2, Malfunction Indicator Light (MIL) | See DIAGNOSTIC CIRCUIT CHECK in BASIC DIAGNOSTIC PROCEDURES | ||
| A-3, No-Start | See NO-START DIAGNOSIS in BASIC DIAGNOSTIC PROCEDURES | ||
| A-5, Fuel Pump Relay | See RELAYS, SOLENOIDS, MOTORS & MODULES in SYSTEM & COMPONENT TESTING | ||
| A-6 & A-7, Fuel System Diagnosis | See BASIC FUEL SYSTEM CHECKS in BASIC DIAGNOSTIC PROCEDURES | ||
| C-1, MAP Sensor | See ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING | ||
| C-1, Power Steering Pressure Switch | See ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING | ||
| C-1, Park/Neutral Switch | See ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING | ||
| C-2, Injector Balance Test (PFI) | See FUEL CONTROL in SYSTEM & COMPONENT TESTING | ||
| C-2, IAC Motor | See IDLE CONTROL SYSTEM in SYSTEM & COMPONENT TESTING | ||
| C-3, Canister Purge System | See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING | ||
| C-4, EST Ignition Check | See BASIC IGNITION SYSTEM CHECKS in BASIC DIAGNOSTIC PROCEDURES | ||
| C-5, ESC Ignition Check | See IGNITION SYSTEM in SYSTEM & COMPONENT TESTING | ||
| C-6, Air Injection System | See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING | ||
| C-7, EGR System | See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING | ||
| C-8, Torque Converter Clutch | See MISCELLANEOUS ECM CONTROLS in SYSTEM & COMPONENT TESTING | ||
| C-8, Manual Transmission Shift Lights | See MISCELLANEOUS ECM CONTROLS in SYSTEM & COMPONENT TESTING | ||
| C-10, A/C Clutch Control | See MISCELLANEOUS ECM CONTROLS in SYSTEM & COMPONENT TESTING | ||
| C-12, Electric Cooling Fan Control | (1) See MISCELLANEOUS ECM CONTROLS in SYSTEM & COMPONENT TESTING | ||
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