Engine Controls - Basic Diagnostic Procedures - 3.4L: Introduction

CAUTION: When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See appropriate COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery.

Before proceeding with basic diagnostic procedures, ensure testing procedure is followed, as some systems which may result in a no-start condition may cause a Diagnostic Trouble Codes (DTC) to be stored in the Powertrain Control Module (PCM). See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in - 3.4L ALERO, GRAND AM, IMPALA & MONTE CARLO article.

If no-start condition still exists after checking and repairing all DTCs, perform a careful and complete visual inspection. Many problems result from mechanical breakdowns, poor electrical connections or damaged/misrouted vacuum hoses. Before condemning the computerized system, perform each test listed in this article.

Use intermittent test procedures to locate driveability problems that do not occur when the vehicle is being tested. These test procedures should also be used if a soft (intermittent) trouble code was present but no problem was found during self-diagnostic testing. See INTERMITTENTS in TROUBLE SHOOTING - NO-CODES - 3.4L ALERO, GRAND AM, IMPALA & MONTE CARLO article.

NOTE: Perform all voltage tests using a Digital Multi-Meter (DMM) or Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure.

NOTE: For specific testing procedures, go to SYSTEM & COMPONENT TESTING - 3.4L ALERO, GRAND AM, IMPALA & MONTE CARLO article. For specifications, go to appropriate ON-VEHICLE ADJUSTMENTS or appropriate SERVICE & ADJUSTMENT SPECIFICATIONS article.