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

EG–428

ENGINE – 2JZ–GE ENGINE TROUBLESHOOTING

DTC 25 26 Air–Fuel Ratio Lean Rich Malfunction

CIRCUIT DESCRIPTION
See page EG–419 for the circuit description

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

(1) (Main heated*1) oxygen sensor voltage is
0.45 V or less (lean) for 90 sec. under codi–
tions (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*1) oxygen
sensor circuit
• (Main heated*1) oxygen sensor
• Ignition system
• ECM

(2)*1 Difference of air–fuel ratio feedback
compensation value between front (No.
1 ~ 3 cylinders) and rear (No. 4 ~ 6
cylinders) is more than 15 percentage for
20 sec. or more under conditions (a)
and (b):
(2 trip detection logic)*2
(a) Engine speed: 2,000 rpm or more
(b) Engine coolant temp.: Between 60°C
(140°F) and 95°C (203°F)
• 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)
• Volume air flow meter (air intake)
• ECM

25

(3)*1 Engine speed varies by more than 15 rpm
over the preceding crank angle period
during a period of 20 sec. or more under
conditions (a) and (b):
(2 trip detection logic)*2
(a) Engine speed: Idling
(b) Engine coolant temp.: Between 60°C
(140°F) and 95°C (203°F)
• 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)
• Volume air flow meter (air intake)
• ECM

(1)*1 Difference of air–fuel ratio feedback
compensation value between front (No.
1 ~ 3 cylinders) and rear (No. 4 ~ 6
cylinders) is more than 15 percentage for
20 sec. or more under conditions (a)
and (b):
(2 trip detection logic)*2
(a) Engine speed: 2,000 rpm or more
(b) Engine coolant temp.: Between 60°C
(140°F) and 95°C (203°F)
• 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)
• Volume air flow meter (air intake)
• ECM

26

(2) Engine speed varies by more than 15 rpm
over the preceding crank angle period
during a period of 20 sec. or more under
conditions (a) and (b):
(2 trip detection logic)*2
(a) Engine speed: Idling
(b) Engine coolant temp.: Between 60°C
(140°F) and 95°C (203°F)
• 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)
• Volume air flow meter (air intake)
• ECM

*1: Only for California specification vehicles
*2: See page EG–397.