2001 Nissan Maxima 20th Anniversary Edition: P0171, P0135, and P0100 Fault Codes Explained
Current Diagnostic Trouble Codes: - P0171: System too lean (Bank 1) - P0135: O2 Heater Circuit Fault (Bank 1, Sensor 1) - P0100: Mass Air Flow (MAF) Circuit Malfunction I recently replaced the Idle Air Control Valve, and the vehicle ran smoothly for approximately two months. However, the same issues have returned. I'm seeking reliable troubleshooting advice to resolve these codes. Any insights or step-by-step guidance would be greatly appreciated! Note: These codes are common in 2001 Nissan Maxima 20th Anniversary Edition models and may indicate underlying sensor or wiring problems.
Check the trouble code section of this forum for detailed causes and solutions. Start with P0100 (MAF circuit) since it often contributes to P0171 (system too lean). P0135 (O2 heater circuit) — the internal resistance should be between 5–15 ohms if the sensor is functioning properly. If the resistance is within range, inspect the wiring and voltage supply for faults. Please update with your findings so we can assist further.