Engine Control System - System/Component Tests: Introduction
Before testing separate components or systems, perform procedures in the BASIC TESTING article. Since many computer-controlled and monitored components set a trouble code if they malfunction, also perform procedures in the TESTS W/CODES article.
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 the WIRING DIAGRAMS
article to isolate wiring harness shorts or opens.
The following table provides the location of commonly used diagnostic information.
GENERAL MOTORS REFERENCE
| System Or Component | Diagnostic Information Location | ||
|---|---|---|---|
| Malfunction Indicator Light (MIL) | See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in BASIC TESTING article | ||
| DLC & MIL On Steady | See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in BASIC TESTING article | ||
| No Scan Tool Data | See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in BASIC TESTING article | ||
| No-Start Diagnosis | See appropriate NO-START - ENGINE CRANKS OKAY in BASIC TESTING article | ||
| Injector Circuit Diagnosis | See BASIC FUEL SYSTEM CHECKS in BASIC TESTING article | ||
| Fuel Pump Relay | See MODULES, MOTORS, RELAYS & SOLENOIDS | ||
| Fuel System Diagnosis | See appropriate BASIC FUEL SYSTEM CHECKS in BASIC TESTING article | ||
| Injector Balance Test | See FUEL SYSTEM | ||
| MAP Sensor | See ENGINE SENSORS & SWITCHES | ||
| Transmission Range Switch | See ENGINE SENSORS & SWITCHES | ||
| IAC Valve | See IDLE CONTROL SYSTEM under FUEL SYSTEM | ||
| Fuel Evaporation Control | See EMISSION SYSTEMS & SUB-SYSTEMS | ||
| Ignition Control Circuit | See IGNITION SYSTEM | ||
| Knock Sensor Check | See IGNITION SYSTEM | ||
| EGR System | See EMISSION SYSTEMS & SUB-SYSTEMS | ||
| Torque Converter Clutch | See MISCELLANEOUS PCM/VCM CONTROLS | ||
| Manual Transmission Shift Lights | See MISCELLANEOUS PCM/VCM CONTROLS | ||
| A/C Clutch Control | (1) See MISCELLANEOUS PCM/VCM CONTROLS | ||
| Electric Cooling Fan Control | (1) See MISCELLANEOUS PCM/VCM CONTROLS | ||
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