Diagnostic Hints - EFI Models

1990 Toyota 4Runner 2D Utility, 3.0 V, StandardSECTION Diagnostic Hints - EFI Models
TROUBLE CODE DIAGNOSTIC HINTS (FUEL INJECTED VEHICLES)

Trouble Code Diagnostic Hints
11 Momentary Interruption Of Power Supply To ECU Could Also Indicate Loss Of ECU E1 Ground Connection
12 No "Ne" (RPM) Ignition Signal To ECU Within 2 Seconds After Engine Is Cranked No "G" Ignition Signal To ECU 2 Times In A Row When Engine Speed Is Between 500-4000 RPM
13 No "Ne" (RPM) Ignition Signal To ECU When Engine Speed Is Above 1500 RPM Signal Is Generated By Pick-Up Coils In Distributor
14 No "IGF" Ignition Signal To ECU From Ignitor Several Times In Succession
21 (1)Detects Deterioration Of Oxygen Sensor
22 Open Or Short In Coolant Temperature Sensor/Switch Signal
24 Open Or Short Circuit In Intake Air Temperature Sensor Signal
25 Open Circuit In O2 Sensor Signal Lean Signal Sent By O2 Sensor For Several Seconds During Air/Fuel Ratio Feedback Correction
26 Rich Signal Sent By O2 Sensor For Several Seconds During Air/Fuel Ratio Feedback Correction
27 Open Or Short In Sub-O2 Sensor Signal
31 & 32 Short Circuit Between Terminals Of Airflow Meter
34 Turbocharger Pressure Is Abnormal Code May Also Set If Airflow Meter Is Faulty
35 Open Circuit In High Altitude Compensator Signal
41 Open Or Short In Throttle Position Sensor Signal "IDL" & "PSW" Signals Are Output At Same Time For Several Seconds
42 No "SPD" Signal From Vehicle Speed Sensor For 8 Seconds With Engine Speed Between 2300-5500 RPM & Coolant Temperature Is Below 176°F (80°C) Except When Racing Engine
43 No "STA" Signal To ECU Until Engine Reaches 800 RPM With Vehicle Not Moving
51 Problem In One Of 3 Switches ECU Monitors, Throttle Position Sensor ("IDL" Signal) Neutral Safety Switch ("NSW" Signal On A/T) A/C Signal To ECU Occurs When TPS Is At Idle & A/C Switch Is On & Check Connector "E1" & "TE1" Is Jumpered
52 Open Or Short Circuit In Knock Sensor Signal
53 Knock Control In ECU Is Faulty
71 EGR Valve Normally Closed, Or Clogged Hose Open Circuit In EGR Temperature Sensor Signal EGR Gas Below Predetermined Level During EGR Control
72 Open Circuit In Fuel-Cut Solenoid Signal
(1) Also detects faults in O2 sensor heater, if equipped.
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

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

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