Code 25 - Air-Fuel Ratio Lean Malfunction

Data Trouble Code No.25 - Air-Fuel Ratio Lean Malfunction

Detecting Condition (2 trip detection logic)
(A) (Main)[1] oxygen sensor voltage is 0.45 volts or less (lean) for 90 seconds under the following conditions:
- Engine coolant temperature 50°C (122°F) or more.
- Engine speed 1,500 rpm or more.
- Vehicle speed below 100 kph (100 mph)
OR

(B) Engine speed varies by more than a predetermined rpm over the preceding crankshaft position during a period of 30 seconds or more under the following conditions;
- Engine speed idling.
- Engine coolant temperature 60°C (140°F) or more.


Trouble Area
If condition (A)
^ Open or short in (Main)[1] oxygen sensor circuit.
^ (Main)[1] oxygen sensor.
^ Ignition system.
^ Engine control module.
If condition (B)
^ Open or short in injector circuit.
^ Fuel line pressure (leak or blockage).
^ Mechanical system malfunction (timing belt skipped).
^ Ignition system
^ Compression pressure.
^ Air leakage.
^ Engine control module.

Malfunction Indicator Lamp
Normal Mode ON
Test Mode ON

Trouble Code Stored In Memory?
YES

[1]"Main" refers to California specification vehicles ONLY.
(non-California models have only 1 oxygen sensor)

NOTE: (2 trip detection logic)
See Description of 2 Trip Detection Logic under "Trouble Code Descriptions".
Diagnostic Trouble Code Descriptions