Engine Controls - System/Component Tests: Introduction

Before testing separate components or systems, perform procedures in BASIC TESTING article. Since many computer-controlled and monitored components set a trouble code if they malfunction, also perform procedures in appropriate (if more than one) TESTS W/CODES article.

NOTE: Testing individual components does not isolate shorts or open circuits. 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 shorted or open wiring harness.

CHART REFERENCE

System Or Component	Diagnostic Information Location
Malfunction Indicator Light	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 ENGINE CRANKS BUT WILL NOT RUN in BASIC TESTING article.
Injector Circuit Diagnosis	See FUEL SYSTEM DIAGNOSIS in BASIC TESTING article.
Fuel Pump Relay	See FUEL PUMP RELAY TESTING in BASIC TESTING article.
Fuel System Diagnosis	See FUEL SYSTEM DIAGNOSIS in BASIC TESTING article.
MAP Sensor	See ENGINE SENSORS & SWITCHES .
IAC Motor	See IDLE CONTROL SYSTEM under FUEL SYSTEM.
Fuel Injector Balance Test	See FUEL CONTROL.
Fuel Evaporation Control	See EMISSION SYSTEMS & SUB-SYSTEMS .
Ignition Control Circuit	See IGNITION SYSTEM in THEORY/OPERATION article.
ESC Ignition Check	See IGNITION SYSTEM in THEORY/OPERATION article.
EGR System	See EMISSION SYSTEMS & SUB-SYSTEMS .
Torque Converter Clutch	See MISCELLANEOUS PCM CONTROLS .
Manual Transmission Shift Lights	See MISCELLANEOUS PCM CONTROLS .
A/C Clutch Control	See MISCELLANEOUS PCM CONTROLS .