TGTE/Troubleshooting 2JZ-GTE — Dtc 25 26 Air–Fuel Ratio Lean Rich Malfunction, page 48

EG–534

ENGINE – 2JZ–GTE ENGINE TROUBLESHOOTING

DTC 25 26 Air–Fuel Ratio Lean Rich Malfunction

CIRCUIT DESCRIPTION

See EG–525 for the circuit description.

DTC No. | Diagnostic Trouble Code Detecting Condition | Trouble Area

25
(1) Main heated oxygen sensor voltage is
0.45 V or less (lean) for 90 sec. under
conditions (a) and (b):
(2 trip detection logic)*2
(a) Engine coolant temp.: 70°C (158°F)
or more
(b) Engine speed: 1,500 rpm or more
• Open or short in main heated oxygen
sensor circuit
• Main heated oxygen sensor
• Ignition system
• ECM

(2) Engine speed varies by more than 20 rpm
over the preceding crank angle period
during a period of 25 sec. or more under
conditions (a) and (b):
(2 trip detection logic).*
(a) Engine speed: Below 950 rpm
(b) Engine coolant temp.: 80°C
(176°F) or
more
• Open and short in injector circuit
• Fuel line pressure (injector leak, blockage)
• Mechanical system malfunction
(skipping teeth of timing belt)
• Ignition system
• Compression pressure (foreign object
caught in valve)
• Mass air flow meter (air intake)
• ECM

26
Engine speed varies by more than 20 rpm over
The preceding crank angle period during a
Period of 25 sec. or more under conditions (a)
And (b):
(2 trip detection logic).*
(a) Engine speed: Below 950 rpm
(b) Engine coolant temp.: 80°C
(176°F) or
more
• Open and short in injector circuit
• Fuel line pressure (injector leak, blockage)
• Mechanical system malfunction
(skipping teeth of timing belt)
• Ignition system
• Compression pressure (foreign object
caught in valve)
• Mass air flow meter (air intake)
• ECM

*: See page EG–503.