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Engine Control System Trouble Shooting - No Codes Toyota Land Cruiser 100

Testing & Diagnostics ~2235 words

INTRODUCTION

Before diagnosing symptoms or intermittent faults, perform steps in appropriate BASIC DIAGNOSTIC PROCEDURES article and appropriate SELF-DIAGNOSTICS article. Use this article to diagnose driveability problems existing when a Diagnostic Trouble Code (DTC) is not present.

Note. Some driveability problems may have been corrected by manufacturer with a revised Engine Control Module (ECM). Check with manufacturer for latest ECM application.

Symptom checks can direct the technician to malfunctioning component(s) for further diagnosis. A symptom should lead to a specific component, system test or adjustment.

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 an intermittent trouble code was present, but no problem was found during self-diagnostic testing.

SYMPTOM DIAGNOSIS

Symptom checks cannot be used properly unless the problem occurs while the vehicle is being tested. To reduce diagnostic time, ensure steps in appropriate BASIC DIAGNOSTIC PROCEDURES and appropriate SELF-DIAGNOSTICS articles were performed before diagnosing a symptom. Symptoms available for diagnosis are as follows

  1. «Does Not Start»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-trouble-shooting-no-codes__does-not-start)
  2. «Difficult To Start»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-trouble-shooting-no-codes__difficult-to-start)
  3. «Poor Idling»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-trouble-shooting-no-codes__poor-idling)
  4. «Poor Driveability»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-trouble-shooting-no-codes__poor-driveability)
  5. «Engine Stalls»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-trouble-shooting-no-codes__engine-stalls)
  6. «Refueling Problem»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-trouble-shooting-no-codes__refueling-problem)
  7. «A/C Switch Indicator Blinking»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-trouble-shooting-no-codes__ac-switch-indicator-blinking)

DOES NOT START

Engine Does Not Crank

  1. Check battery and battery cables.
  2. Check starter. See appropriate STARTERS article in STARTING & CHARGING SYSTEMS.
  3. Check starter relay. See appropriate STARTERS article in STARTING & CHARGING SYSTEMS.

No Initial Combustion

  1. Check ECM power source circuit. See ELECTRONIC CONTROL MODULE (ECM) POWER SOURCE CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article.
  2. Check engine immobilizer system (if equipped). See appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.
  3. On all models except Camry CNG, Land Cruiser and Tundra V8, check fuel pump control circuit. See FUEL PUMP CONTROL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article. On Land Cruiser, perform DTC P1200: FUEL PUMP RELAY/ECU CIRCUIT test in SELF-DIAGNOSTICS - LAND CRUISER article. On Camry CNG, check fuel shutoff valve circuit. See DTC P1190: FUEL PRESSURE REGULATOR MALFUNCTION test in SELF-DIAGNOSTICS - CAMRY CNG article. On Tundra V8, check fuel pump control circuit. See DTC P1200: FUEL PUMP RELAY CIRCUIT test in SELF-DIAGNOSTICS - TUNDRA V8 article.
  4. On Land Cruiser, check fuel pump switch. See FUEL DELIVERY under FUEL SYSTEM in SYSTEM & COMPONENT TESTING - V6 & V8 articles.
  5. Check Electronic Control Module (ECM) connector for loose, damaged or corroded terminals and repair as necessary. If connector is okay, check ECM ground circuits. See GROUND DISTRIBUTION article in WIRING DIAGRAMS. Repair as necessary. If ground circuits are okay, replace ECM with a known-good ECM and retest.

No Complete Combustion

  1. On all models except Camry CNG, Land Cruiser and Tundra V8, check fuel pump control circuit. See FUEL PUMP CONTROL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article. On Land Cruiser, perform DTC P1200: FUEL PUMP RELAY/ECU CIRCUIT test in SELF-DIAGNOSTICS - LAND CRUISER article. On Camry CNG, check fuel shutoff valve circuit. See DTC P1190: FUEL PRESSURE REGULATOR MALFUNCTION test in SELF-DIAGNOSTICS - CAMRY CNG article. On Tundra V8, check fuel pump control circuit. See DTC P1200: FUEL PUMP RELAY CIRCUIT test in SELF-DIAGNOSTICS - TUNDRA V8 article.

DIFFICULT TO START

Note. On Celica and ECHO, starter signal circuit testing information is not available from manufacturer.

Difficult To Start, Cranks Normal

  1. Check starter signal circuit. See STARTER SIGNAL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article.
  2. On all models except Camry CNG, Land Cruiser and Tundra V8, check fuel pump control circuit. See FUEL PUMP CONTROL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article. On Land Cruiser, perform DTC P1200: FUEL PUMP RELAY/ECU CIRCUIT test in SELF-DIAGNOSTICS - LAND CRUISER article. On Camry CNG, check fuel shutoff valve circuit. See DTC P1190: FUEL PRESSURE REGULATOR MALFUNCTION test in SELF-DIAGNOSTICS - CAMRY CNG article. On Tundra V8, check fuel pump control circuit. See DTC P1200: FUEL PUMP RELAY CIRCUIT test in SELF-DIAGNOSTICS - TUNDRA V8 article.
  3. Check engine compression. See appropriate BASIC DIAGNOSTIC PROCEDURES article.

Difficult To Start When Cold

  1. Check starter signal circuit. See STARTER SIGNAL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article.
  2. On all models except Camry CNG, Land Cruiser and Tundra V8, check fuel pump control circuit. See FUEL PUMP CONTROL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article. On Land Cruiser, perform DTC P1200: FUEL PUMP RELAY/ECU CIRCUIT test in SELF-DIAGNOSTICS - LAND CRUISER article. On Camry CNG, check fuel shutoff valve circuit. See DTC P1190: FUEL PRESSURE REGULATOR MALFUNCTION test in SELF-DIAGNOSTICS - CAMRY CNG article. On Tundra V8, check fuel pump control circuit. See DTC P1200: FUEL PUMP RELAY CIRCUIT test in SELF-DIAGNOSTICS - TUNDRA V8 article.

Difficult To Start When Hot

  1. Check starter signal circuit. See STARTER SIGNAL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article.
  2. On all models except Camry CNG, Land Cruiser and Tundra V8, check fuel pump control circuit. See FUEL PUMP CONTROL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article. On Land Cruiser, perform DTC P1200: FUEL PUMP RELAY/ECU CIRCUIT test in SELF-DIAGNOSTICS - LAND CRUISER article. On Camry CNG, check fuel shutoff valve circuit. See DTC P1190: FUEL PRESSURE REGULATOR MALFUNCTION test in SELF-DIAGNOSTICS - CAMRY CNG article. On Tundra V8, check fuel pump control circuit. See DTC P1200: FUEL PUMP RELAY CIRCUIT test in SELF-DIAGNOSTICS - TUNDRA V8 article.

POOR IDLING

High Idle Speed

  1. Check A/C compressor signal circuit. See appropriate AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
  2. Check ECM power source circuit. See ELECTRONIC CONTROL MODULE (ECM) POWER SOURCE CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article.

Low Idle Speed

  1. Check A/C compressor signal circuit. See appropriate AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
  2. On all models except Camry CNG, Land Cruiser and Tundra V8, check fuel pump control circuit. See FUEL PUMP CONTROL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article. On Land Cruiser, perform DTC P1200: FUEL PUMP RELAY/ECU CIRCUIT test in SELF-DIAGNOSTICS - LAND CRUISER article. On Camry CNG, check fuel shutoff valve circuit. See DTC P1190: FUEL PRESSURE REGULATOR MALFUNCTION test in SELF-DIAGNOSTICS - CAMRY CNG article. On Tundra V8, check fuel pump control circuit. See DTC P1200: FUEL PUMP RELAY CIRCUIT test in SELF-DIAGNOSTICS - TUNDRA V8 article.

Rough Idle

  1. Check engine compression. See appropriate BASIC DIAGNOSTIC PROCEDURES article.
  2. On all models except Camry CNG, Land Cruiser and Tundra V8, check fuel pump control circuit. See FUEL PUMP CONTROL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article. On Land Cruiser, perform DTC P1200: FUEL PUMP RELAY/ECU CIRCUIT test in SELF-DIAGNOSTICS - LAND CRUISER article. On Camry CNG, check fuel shutoff valve circuit. See DTC P1190: FUEL PRESSURE REGULATOR MALFUNCTION test in SELF-DIAGNOSTICS - CAMRY CNG article. On Tundra V8, check fuel pump control circuit. See DTC P1200: FUEL PUMP RELAY CIRCUIT test in SELF-DIAGNOSTICS - TUNDRA V8 article.

Surging

  1. Check ECM power source circuit. See ELECTRONIC CONTROL MODULE (ECM) POWER SOURCE CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article.
  2. On all models except Camry CNG, Land Cruiser and Tundra V8, check fuel pump control circuit. See FUEL PUMP CONTROL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article. On Land Cruiser, perform DTC P1200: FUEL PUMP RELAY/ECU CIRCUIT test in SELF-DIAGNOSTICS - LAND CRUISER article. On Camry CNG, check fuel shutoff valve circuit. See DTC P1190: FUEL PRESSURE REGULATOR MALFUNCTION test in SELF-DIAGNOSTICS - CAMRY CNG article. On Tundra V8, check fuel pump control circuit. See DTC P1200: FUEL PUMP RELAY CIRCUIT test in SELF-DIAGNOSTICS - TUNDRA V8 article.

POOR DRIVEABILITY

Hesitation/Poor Acceleration

  1. On all models except Camry CNG, Land Cruiser and Tundra V8, check fuel pump control circuit. See FUEL PUMP CONTROL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article. On Land Cruiser, perform DTC P1200: FUEL PUMP RELAY/ECU CIRCUIT test in SELF-DIAGNOSTICS - LAND CRUISER article. On Camry CNG, check fuel shutoff valve circuit. See DTC P1190: FUEL PRESSURE REGULATOR MALFUNCTION test in SELF-DIAGNOSTICS - CAMRY CNG article. On Tundra V8, check fuel pump control circuit. See DTC P1200: FUEL PUMP RELAY CIRCUIT test in SELF-DIAGNOSTICS - TUNDRA V8 article.
  2. Check for faulty automatic transmission (electronics). See appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS.
  3. On Corolla, check A/C cut control circuit. See A/C-CUT CONTROL SYSTEM CIRUCIT under COMPUTERIZED ENGINE CONTROLS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article.

Surging

  1. On all models except Camry CNG, Land Cruiser and Tundra V8, check fuel pump control circuit. See FUEL PUMP CONTROL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article. On Land Cruiser, perform DTC P1200: FUEL PUMP RELAY/ECU CIRCUIT test in SELF-DIAGNOSTICS - LAND CRUISER article. On Camry CNG, check fuel shutoff valve circuit. See DTC P1190: FUEL PRESSURE REGULATOR MALFUNCTION test in SELF-DIAGNOSTICS - CAMRY CNG article. On Tundra V8, check fuel pump control circuit. See DTC P1200: FUEL PUMP RELAY CIRCUIT test in SELF-DIAGNOSTICS - TUNDRA V8 article.

ENGINE STALLS

Engine Stall After Start

  1. Check engine immobilizer system. See appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.
  2. On all models except Camry CNG, Land Cruiser and Tundra V8, check fuel pump control circuit. See FUEL PUMP CONTROL CIRCUIT under COMPUTERIZED ENGINE CONTROLS in appropriate SYSTEM & COMPONENT TESTING article. On Land Cruiser, perform DTC P1200: FUEL PUMP RELAY/ECU CIRCUIT test in SELF-DIAGNOSTICS - LAND CRUISER article. On Camry CNG, check fuel shutoff valve circuit. See DTC P1190: FUEL PRESSURE REGULATOR MALFUNCTION test in SELF-DIAGNOSTICS - CAMRY CNG article. On Tundra V8, check fuel pump control circuit. See DTC P1200: FUEL PUMP RELAY CIRCUIT test in SELF-DIAGNOSTICS - TUNDRA V8 article.

Engine Stall During A/C Operation

  1. Check A/C compressor signal circuit. See appropriate AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
  2. Check Electronic Control Module (ECM) connector for loose, damaged or corroded terminals and repair as necessary. If connector is okay, check ECM ground circuits. See GROUND DISTRIBUTION article in WIRING DIAGRAMS. Repair as necessary. If ground circuits are okay, replace ECM with a known-good ECM and retest.

REFUELING PROBLEM

Note. This only applies to vehicles equipped with On-Board Refilling Vapor Recovery (ORVR) system.

Unable/Difficult To Refuel

  1. Check ORVR system (if equipped). See FUEL EVAP SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article.
  2. Check fuel Evaporation (EVAP) system. See FUEL EVAP SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article.

A/C SWITCH INDICATOR BLINKING

Note. Testing procedure for this symptom was only available for Camry 4-cylinder CNG, Camry 4-cylinder gasoline and Camry Solara 4-cylinder models.

  1. Check A/C compressor lock sensor circuit. See A/C COMPRESSOR LOCK SENSOR CIRCUIT under COMPUTERIZED ENGINE CONTROLS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article.
  2. Check A/C evaporator temperature sensor circuit. See A/C EVAPORATOR TEMPERATURE SENSOR CIRCUIT under COMPUTERIZED ENGINE CONTROLS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article.

INTERMITTENT PROBLEM DIAGNOSIS

Intermittent fault testing requires duplicating circuit or component failure to identify the problem. These procedures may lead to the computer setting a fault code (on some systems) which may help in diagnosis.

If problem vehicle does not produce fault codes, monitor voltage or resistance values using a DVOM while attempting to reproduce conditions causing intermittent fault. A status change on DVOM indicates a fault has been located.

Use a DVOM to pinpoint faults. When monitoring voltage, ensure ignition switch is in ON position or engine is running. Ensure ignition switch is in OFF position or negative battery cable is disconnected when monitoring circuit resistance. Status changes on DVOM during test procedures indicate area of fault.

Intermittent Simulation

To reproduce the conditions creating an intermittent fault, use the following methods

  1. Lightly vibrate component. See «VIBRATION METHOD»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-trouble-shooting-no-codes) .
  2. Heat component. See «HEATING METHOD»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-trouble-shooting-no-codes) .
  3. Wiggle or bend wiring harness. See «VIBRATION METHOD»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-trouble-shooting-no-codes) .
  4. Spray component with water. See «WATER SPRINKLING METHOD»(/toyota/land-cruiser/100-1998-2002/remont/testing-diagnostics/#engine-control-system-trouble-shooting-no-codes__water-sprinkling-method) .

Monitor circuit/component voltage or resistance while simulating intermittent. If engine is running, monitor for Diagnostic Trouble Codes (DTCs). Use test results to identify a faulty component or circuit.

Wiring Harness Testing

Using DVOM, monitor suspected circuit or component. Lightly shake wiring harness while noting fluctuation in DVOM reading. Inspect component connector harness for stretched areas. Inspect wiring harness at area where it goes through the body.

Component, Relay & Sensor Testing

Using DVOM, monitor suspected circuit or component. Lightly vibrate suspected component, relay or sensor while noting fluctuation in DVOM reading.

Electrical Connector Testing

Using DVOM, monitor suspected circuit or component. Lightly shake electrical connector while noting fluctuation in DVOM reading. Visually inspect electrical connector for damage.

Component Testing

Heat suspected component with a hair dryer while checking for a malfunction to occur. DO NOT apply heat directly to components in Engine Control Module (ECM). DO NOT heat any component to more than 140°F (60°C).

WATER SPRINKLING METHOD

CAUTIONEnsure vehicle does not have water leaks before using water sprinkling method. If water leak exists, use care when applying water that no water is sprayed directly on any electronic components.

Spray outside of vehicle and front of radiator with water while checking for a malfunction to occur. DO NOT spray water directly into engine compartment. Temperature and humidity may be changed by spraying water onto front of radiator. DO NOT spray electronic components directly with water.

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