Section 9 (Engine Controls - Basic Engine Testing - 2.4L): Introduction

1998 Oldsmobile Achieva 3.1 M, 4T40E/MN4SECTION Introduction
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 1997 Pontiac Sunfire, 1997 Pontiac Grand Am, 1997 Oldsmobile Achieva, 1997 Chevrolet Malibu, and 1997 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.

The following diagnostic steps will help prevent overlooking a simple problem. This is also where to begin diagnosis for a no-start condition.

The first step in diagnosing any driveability problem is verifying the customer's complaint with a test drive under the conditions during which the problem reportedly occurred.

Before entering self-diagnostics, perform a careful and complete visual inspection. Most engine control 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.

NOTE: Unless otherwise instructed in test procedures, perform all voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance.

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 CHECKΒ 
DLC Diagnosis See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECKΒ 
No-Start Diagnosis See NO START - ENGINE CRANKS OKAYΒ 
No Scan Tool Data See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECKΒ 
Fuel Pump Relay See FUEL SYSTEM in SYSTEM/COMPONENT TESTS article
Fuel System Diagnosis See BASIC FUEL SYSTEM CHECKSΒ 
MAP Sensor See ENGINE SENSORS & SWITCHES in SYSTEM/COMPONENT TESTS article
Power Steering Pressure Switch See ENGINE SENSORS & SWITCHES in SYSTEM/COMPONENT TESTS article
Transmission Range Switch See ENGINE SENSORS & SWITCHES in SYSTEM/COMPONENT TESTS article
Injector Balance Test See FUEL SYSTEM in SYSTEM/COMPONENT TESTS article
Injector Leak Test See FUEL SYSTEM in SYSTEM/COMPONENT TESTS article
IAC Motor See IDLE CONTROL SYSTEM in SYSTEM/COMPONENT TESTS article
Canister Purge System See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM/COMPONENT TESTS article
Knock Sensor Check See IGNITION SYSTEM in SYSTEM/COMPONENT TESTS article
Air Injection System See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM/COMPONENT TESTS article
EGR System See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM/COMPONENT TESTS article
1-4 Upshift System (Manual Transmission) See MISCELLANEOUS CONTROLS SYSTEM/COMPONENT TESTS article
Torque Converter Clutch (1) See MISCELLANEOUS CONTROLS in SYSTEM/COMPONENT TESTS article
A/C Compressor Clutch Control (2) See MISCELLANEOUS CONTROLS in SYSTEM/COMPONENT TESTS article
Electric Cooling Fan Control (2) See MISCELLANEOUS CONTROLS in SYSTEM/COMPONENT TESTS article
Engine Coolant Level Switch See ENGINE SENSORS & SWITCHES in SYSTEM/COMPONENT TESTS article
Oil Pressure Switch See ENGINE SENSORS & SWITCHES in SYSTEM/COMPONENT TESTS article
Oil Level Sensor See ENGINE SENSORS & SWITCHES in SYSTEM/COMPONENT TESTS article
PCM Controlled Warning Lights See MISCELLANEOUS CONTROLS in SYSTEM/COMPONENT TESTS article
Supercharger Boost Control See AIR INDUCTION SYSTEMS in SYSTEM/COMPONENT TESTS article
(1) Covered in entirety in the TRANSMISSION SERVICING article.
(2) Covered in entirety in the A/C-HEATER SYSTEM article.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.