LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Toyota >> 1998 >> 4Runner Base, 4WD, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Tests W/Codes - 4-Cylinder >> Diagnostic Trouble Code Definitions
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Trouble Code Definitions

DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS

DTC Description
P0100 (1) Mass Airflow (MAF) Sensor Circuit
P0101 (1) Mass Airflow (MAF) Circuit Range/Performance Problem
P0110  Intake Air Temperature (IAT) Sensor Circuit
P0115  Engine Coolant Temperature (ECT) Sensor Circuit
P0116 (1) Engine Coolant Temperature (ECT) Sensor Circuit Range/Performance Problem
P0120  Throttle Position (TP) Sensor Circuit Malfunction
P0121 (1) Throttle Position (TP) Sensor Circuit Range/Performance Problem
P0125  Insufficient Coolant Temperature For Closed Loop Fuel Control
P0130 (1) (2) Heated Oxygen Sensor Circuit (Sensor No. 1)
P0133 (1) (2) Heated Oxygen Sensor Circuit (Sensor No. 1) Slow Response
P0135 (1) Heated Oxygen Sensor Circuit
P0136 (1) (2) Heated Oxygen Sensor Circuit (Sensor No. 2)
P0141 (1) Heated Oxygen Sensor Circuit
P0171 (1) System Too Lean (Fuel Trim)
P0172 (1) System Too Rich (Fuel Trim)
P0300  Random Misfire Detected
P0301 (1) Cylinder No. 1 Misfire Detected
P0302 (1) Cylinder No. 2 Misfire Detected
P0303 (1) Cylinder No. 3 Misfire Detected
P0304 (1) Cylinder No. 4 Misfire Detected
P0325  Knock Sensor Circuit
P0335 (1) Crankshaft Position (CKP) Sensor Circuit
P0340 (1) Camshaft Position (CMP) Sensor Circuit
P0401 (1) Insufficient Exhaust Gas Recirculation (EGR) Flow Detected
P0402 (1) Excessive Exhaust Gas Recirculation (EGR) Flow Detected
P0420 (1) Catalyst System Efficiency Below Threshold
P0440 (1) Evaporative Emission Control System Malfunction
P0441 (1) Incorrect EVAP Purge Flow
P0446 (1) EVAP Vent Control Malfunction
P0450  EVAP Pressure Sensor Fault
P0451  EVAP Pressure Sensor Range/Performance
P0500 (1) Vehicle Speed Sensor Fault
P0505 (1) Idle Air Control (IAC) System Malfunction
P1300  Ignitor Circuit No. 1 Fault
P1310  Ignitor Circuit No. 2 Fault
P1335  Crankshaft Position (CKP) Sensor Circuit
P1520 (1) Stoplight Switch Signal Malfunction (A/T Only)
P1600  ECM BATT Malfunction
P1780 (1) Park/Neutral Position (PNP) Switch
(1) Two-trip detection logic code. For more information, see TWO-TRIP DETECTION LOGIC in TESTS W/CODES - INTRODUCTION.
(2) Some models are equipped with non-heated oxygen sensors.