Manual sections Wiring diagrams
Repair manual

Theory & Operation GMC Envoy I

Step-by-step instructions on "Theory & Operation" for GMC Envoy I (1997–2000). Pick an article — removal, installation, adjustment and diagnostics with illustrations.

Introduction

Speed Density

Computerized Engine Controls

Powertrain Control Module (PCM) & Vehicle Control Module Vcm)

Arithmetic Logic Unit (Alu)

Central Processing Unit (Cpu)

Power Supply

Memories

Input Devices

A/c on (A/c Request) Signal

Battery Voltage

Brake Switch Feedback

Camshaft Position (Cmp) Sensor

Cranking Signal

Crankshaft Position (Ckp) Sensor

Digital Ratio Adapter Controller (Drac)

Engine Coolant Temperature (ECT) Sensor

Exhaust Gas Recirculation (EGR) Pintle Position

Fuel Pump Feedback

Gear Switches

Intake Air Temperature (IAT) Sensor

Knock Sensor (Ks)

Manifold Absolute Pressure (MAP) Sensor

Oxygen Sensor (O2S)

Park/neutral Position (Pnp) Switch

Transmission Fluid Pressure (Tfp) Switch (4L60-E & 4L80-E Transmission)

Throttle Position (Tp) Sensor

Transmission Fluid Temperature (Tft) Sensor (4L60-E, 4L80-E & 4T60-E Transmission)

Vehicle Speed Sensor (Vss)

Output Signals

A/c Clutch Relay

Cruise Control Stepper Motor

Malfunction Indicator Light (MIL)

EGR System

Electronic Ignition (Ei)

Fuel Injectors

Fuel Pump & Fuel Pump Relay

Idle Air Control (Iac) Valve

Self-Diagnostics

Serial Data

Shift Solenoids (4L60-E, 4L80-E & 4T60-E Transmission)

Torque Converter Clutch (Tcc)

Transmission Shift Light (Manual Transmission)

Fuel Pump

Fuel Pressure Regulator (Csi)

Fuel Pressure Regulator (Sfi)

Fuel Pump Relay

Fuel Control

Open Loop

Closed Loop

Central Sequential Port Injection (Csi)

Sequential Fuel Injection (Sfi)

Fuel System Operating Modes

Idle Speed

Enhanced Ignition System

Ignition Timing Control

Catalytic Converter

Exhaust Gas Recirculation (EGR)

Evaporative Emission System

Carbon Canister

Canister Purge Control Solenoid (Cpcs)

Positive Crankcase Ventilation (PCV)

Self-Diagnostic System

Miscellaneous Pcm/vcm Controls

A/c Clutch

A/c Pressure Switches

Cruise Control

Electronic Transmission (4L60-E, 4L80-E & 4T60-E)

Shift Light