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Engine Controls - System/component Tests Lexus LS I

Step-by-step instructions on "Engine Controls - System/component Tests" for Lexus LS I (1989–1994). Pick an article — removal, installation, adjustment and diagnostics with illustrations.

INTRODUCTION

CONTROL UNIT

ES250 POWER CIRCUITS

ES250 GROUND CIRCUITS

LS400 GROUND CIRCUITS

AIRFLOW METER AIR TEMPERATURE SENSOR RESISTANCE

ES250 AIRFLOW METER MEASURING PLATE RESISTANCE

ES250 CLUTCH START SWITCH

NEUTRAL START SWITCH

THROTTLE POSITION SENSOR (TPS)

CIRCUIT OPENING RELAY

EFI MAIN RELAY

STARTER RELAY

FUEL CONTROL SYSTEM

FUEL CUT SYSTEM

FUEL PRESSURE CONTROL SYSTEM

IGNITION COILS SYSTEM

ADVANCE COMPONENTS

VACUUM MODULATOR CHECK

ES250 BIMETALLIC VACUUM SWITCHING VALVE

LS400 VACUUM SWITCHING VALVE

EVAP CANISTER

BIMETALLIC VACUUM SWITCHING VALVE

EVAP VACUUM CONTROL VALVE (LS400)

PCV VALVE

DASHPOT

A/C CLUTCH CONTROL

A/C CLUTCH RELAY CONTROL

LS400 A/C PRESSURE SWITCH

ES250 COOLING FAN ECU

ES250 WATER TEMPERATURE SENSOR

LS400 WATER TEMPERATURE SWITCH

ES250 & LS400 ENGINE MAIN & LS400 COOLING FAN RELAY NO. 3

COOLING FAN RELAY NO. 1 (ES250 & LS400) & NO. 2 (LS400)

ES250 COOLING FAN RELAY NO. 2

ES250 COOLING FAN RELAY NO. 3

COOLING FAN MOTORS NO. 1 & NO. 2

FAILURE SYMPTOMS & CIRCUIT TESTS

ES250 THEFT DETERRENT ECU POWER CIRCUIT TEST

LS400 THEFT DETERRENT ECU POWER CIRCUIT TEST

ES250 THEFT DETERRENT IGNITION SWITCH CIRCUIT TEST

LS400 THEFT DETERRENT IGNITION SWITCH CIRCUIT TEST

ES250 THEFT DETERRENT KEY UNLOCK WARNING SWITCH CIRCUIT TEST

LS400 THEFT DETERRENT KEY UNLOCK WARNING SWITCH CIRCUIT TEST

ES250 THEFT DETERRENT STARTER CUT SYSTEM CIRCUIT TEST

LS400 THEFT DETERRENT STARTER CUT SYSTEM CIRCUIT TEST

LS400 THEFT DETERRENT ECU OPERATION TEST

LS400 THEFT DETERRENT ECU GROUND CIRCUIT TEST

CIRCUIT DIAGNOSIS CHARTS (LS400)

EFI ECU TERMINAL IDENTIFICATION

CIRCUIT DIAGNOSIS CHARTS