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Engine Controls - System & Component Testing - 6.5L: Introduction

Before testing separate components or systems, perform procedures in the BASIC TESTING - 6.5L DIESEL article. Since many computer-controlled and monitored components set a trouble code if they malfunction, also perform procedures in the TESTS W/CODES - 6.5L 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 - 6.5L DIESEL article
DLC & MIL On Steady See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in BASIC TESTING - 6.5L DIESEL article
No Scan Tool Data See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in BASIC TESTING - 6.5L DIESEL article
No-Start Diagnosis See appropriate NO-START - ENGINE CRANKS OKAY in BASIC TESTING - 6.5L DIESEL article
Injector Circuit Diagnosis See BASIC FUEL SYSTEM CHECKS in BASIC TESTING - 6.5L DIESEL article
Fuel Pump Relay See MODULES, MOTORS, RELAYS & SOLENOIDS 
Fuel System Diagnosis See appropriate BASIC FUEL SYSTEM CHECKS in BASIC TESTING - 6.5L DIESEL article
Injector Balance Test See FUEL SYSTEM 
MAP Sensor See ENGINE SENSORS & SWITCHES 
Transmission Range Switch See ENGINE SENSORS & SWITCHES 
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 CONTROLS 
Manual Transmission Shift Lights See MISCELLANEOUS PCM CONTROLS 
A/C Clutch Control (1) See MISCELLANEOUS PCM CONTROLS 
Electric Cooling Fan Control (1) See MISCELLANEOUS PCM CONTROLS 
(1) Complete coverage in the A/C-HEATER SYSTEM article in the AIR CONDITIONING & HEAT section.