Home/Chevrolet/Astro/Chevrolet Astro I (1985-2005)/Repair manual/Engine Controls - System/component Tests - 4.3l./Required Service

Contents

Wiring diagrams Section: Engine Controls - System/component Tests - 4.3l.

MODEL IDENTIFICATION

TERMINOLOGY

INTRODUCTION

CONTROL UNIT

Ground Circuits

Power Circuits

A/C ON SWITCH/SYSTEM TEST

BRAKE SWITCH

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

INTAKE AIR TEMPERATURE (IAT) SENSOR

KNOCK SENSOR

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR

OXYGEN SENSOR (O2S)

OXYGEN SENSOR HEATING ELEMENT

THROTTLE POSITION (TP) SENSOR

TRANSMISSION RANGE SWITCH

VEHICLE SPEED SENSOR (PM GENERATOR)

A/C Relays

Fuel Pump Relay

SOLENOIDS

Electronic Air Control (EAC) Solenoid

EGR Control Solenoid

Idle Air Control (IAC) Valve

Torque Converter Clutch (TCC) Solenoid

FUEL DELIVERY

Fuel Pressure Regulator (Port Fuel Injection)

Fuel Pressure Regulator (Central & Throttle Body Injection)

Fuel Pump Oil Pressure Switch (Back-Up Circuit)

Fuel Pump Relay By-Pass Procedure

Fuel Injector(s)

C-2, Port Fuel Injector Balance Test

IGNITION SYSTEM

C-4, Ignition Control Circuit

C-5, Knock Sensor Circuit (Models Using External Spark Controller Module)

C-5, Knock Sensor Circuit (Models Using Knock Sensor With Internal Spark Controller Module)

System Test (Vacuum-Controlled Valve)

Negative Backpressure EGR Valve

Linear EGR Valve (Digital Valve)

Vapor Canister Purge Valve ("P" Series & 4.3L CPI)

Fuel Tank Pressure Control Valve ("C", "G", "K" & "M" Series -High-Altitude)

Thermostatic Vacuum Switch

Required Service

Checking PCV Valve Function

Damper Door - Wax Pellet Check

MISCELLANEOUS ECM/PCM/VCM CONTROLS

Converter Lock-Up Signal At Transmission

Converter Lock-Up Signal From ECM/PCM/VCM

Shift Light (Manual Transmission)

A/C CLUTCH (C-10) & ELECTRIC COOLING FAN (C-12)

A/C Clutch Relay

COOLING FAN (C-12)

Cooling Fan Relay

Cooling Fan Motor

DIAGNOSTIC CHARTS

CHART C-10, A/C COMPRESSOR CLUTCH CIRCUIT DIAGNOSIS - 4.3L (VIN W & Z) S" & "T" SERIES A/T & 4.3L (VIN W) "T" SERIES M/T

Diagnostic Aids

CHART C-10, A/C COMPRESSOR CLUTCH CIRCUIT DIAGNOSIS 4.3L (VIN Z) "S" & "T" SERIES M/T (1 OF 2)

CHART C-10, A/C COMPRESSOR CLUTCH CIRCUIT DIAGNOSIS 4.3L (VIN Z) "S" & "T" SERIES M/T (2 OF 2)

A/C REQUEST SIGNAL CIRCUIT DIAGNOSIS - 4.3L VIN W & Z ("C", "G", "K", "L", "M" & "P" SERIES)

All sections

Required Service Chevrolet Astro I

Engine Controls - System/component Tests - 4.3l.

Required Service

The PCV system may require service for obstructions if any of the following conditions exist

Rough Idle
Stalling or Slow Idle Speed
Oil Leaks
Oil in Air Cleaner
Sludge in Engine

A leaking PCV valve or hose could cause

Rough Idle
Stalling
High Idle Speed

If engine idles roughly, check for clogged PCV valve and for plugged or broken PCV hoses BEFORE adjusting idle. Check correct PCV valve application to ensure the correct valve is fitted. Replace PCV valve if required.