Problem: Check engine Light stays on in warm weather.
Toyota, RAV4, 2000, engine size: 2 Liters, 39,000 miles,
OBD2 Code Reader Indicates Two Error Codes:
1) PO171: System Too Lean (Bank 1)
2) P1130: Air-Fuel Sensor Circuit Range / Performance.
What do I need to replace to fix the Check engine Light so I do not have the check engine light on all the time?
First thing I would check for is an air leak such as on the snorkel going to the throttle body. Also check the oil cap, dipstick and pcv valve for proper seating. The first code is probably the result of the second one.
However the strategy is to check the po171 first. It isn't as simple as just replacing a part based on a code as autozone would like you to think.
According to Mitchell 1:
Since the problem happens in warm weather. I would lean towards testing the ECT as well as checked the the air leak.