Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2003 Toyota Avalon XLSFACTORY OEM SERVICE PROCEDURE
Engine Control System Self Diagnostics
- Introduction
- Self-Diagnostic System
- Testing Procedure
- System Overview
- Two-Trip Detection Logic
- Freeze Frame Data
- Malfunction Indicator Light Inspection
- Retrieving Diagnostic Trouble Codes
- Clearing Diagnostic Trouble Codes
- Engine Control Module Location
- Fail-Safe Chart
- Intermittent Problems Check (Hand-Held Tester Only)
- Basic Inspection
- Engine Operating Condition
- Test Drive Confirmation
- Programming
- Scan Tool Problems
- Summary
- Diagnostic Trouble Code Definitions
- Diagnostic Tests
- Notes
- DTC P0010: Camshaft Position "A" Actuator Circuit (Bank No. 1) & DTC P0020: Camshaft Position "A" Actuator Circuit (Bank No. 2)
- DTC P0011, DTC P0012, DTC P0021 & DTC P0022
- DTC P0016: Crankshaft Position - Camshaft Position Correlation (Bank No. 1 Sensor "A") & DTC P0018 Crankshaft Position - Camshaft Position Correlation (Bank No. 2 Sensor "A")
- DTC P0036: Oxygen Sensor Heater Control Circuit (Bank No. 1 Sensor No. 2)
- DTC P0100: Mass Or Volume Air Flow Circuit
- DTC P0101: Mass Or Volume Air Flow Circuit Range/Performance Problem
- DTC P0110: Intake Air Temperature Circuit
- DTC P0115: Engine Coolant Temperature Circuit
- DTC P0116: Engine Coolant Temperature Circuit Range/Performance Problem & DTC P0125: Insufficient Coolant Temperature For Closed Loop Fuel Control
- DTC P0120: Throttle/Pedal Position Sensor/Switch "A" Circuit
- DTC P0121: Throttle/Pedal Position Sensor/Switch "A" Circuit Range/Performance Problem
- DTC P0128: Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
- DTC P0134: Oxygen Sensor Circuit No Activity Detected (Bank No. 1 Sensor No. 1) & DTC P0154: Oxygen Sensor Circuit No Activity Detected (Bank No. 2 Sensor No. 1)
- DTC P0135: A/F Sensor Heater Circuit (Bank No. 1 Sensor No. 1) & DTC P0155: A/F Sensor Heater Circuit (Bank No. 2 Sensor No. 1)
- DTC P0136: Oxygen Sensor Circuit Malfunction (Bank No. 1 Sensor No. 2)
- DTC P0171, DTC P0172, DTC P0174 & DTC P0175
- DTC P0300, DTC P0301, DTC P0302, DTC P0303, DTC P0304, DTC P0305 & DTC P0306
- DTC P0325: Knock Sensor No. 1 Circuit (Bank No. 1 Or Single Sensor) & DTC P0330: Knock Sensor No. 2 Circuit (Bank No. 2)
- DTC P0335: Crankshaft Position Sensor "A" Circuit & DTC P0339: Crankshaft Position Sensor Circuit Intermittent
- DTC P0340, DTC P0341, DTC P0345 & DTC P0346
- DTC P0351, DTC P0352, DTC P0353, DTC P0354, DTC P0355 & DTC P0356
- DTC P0420: Catalyst System Efficiency Below Threshold (Bank No. 1)
- DTC P0441: EVAP Incorrect Purge Flow & DTC P0446: EVAP Vent Control Malfunction
- DTC P0442: EVAP Leak Detected (Small Leak) & DTC P0456: EVAP Leak Detected (Very Small Leak)
- DTC P0450: EVAP Pressure Sensor/Switch & DTC P0451: EVAP Pressure Sensor/Switch Range/Performance
- DTC P0500: Vehicle Speed Sensor "A"
- DTC P0505: Idle Air Control System & DTC P0511: Idle Air Control Circuit
- DTC P0560: System Voltage
- DTC P0705: Transmission Range Sensor Circuit Malfunction (PRNDL Input) & DTC P0850: Park/Neutral Switch Input Circuit
- DTC P0724: Brake Switch "B" Circuit High
- DTC P2195, DTC P2196, DTC P2197 & DTC P2198
- DTC P2237: A/F Sensor Circuit (Bank No. 1 Sensor No. 1) & DTC P2240: A/F Sensor Circuit (Bank No. 2 Sensor No. 1)
- DTC P2A00: A/F Sensor Circuit Slow Response (Bank No. 1 Sensor No. 1) & DTC P2A03: A/F Sensor Circuit Slow Response (Bank No. 2 Sensor No. 1)
Factory Service Tools
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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.
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