Diag Code
25
Air–fuel Ratio Lean Malfunction
Diag. Code
26
Air–fuel Ratio Rich Malfunction
CIRCUIT DESCRIPTION
The main oxygen sensor is located in the exhaust manifold. It indirectly determines whether the fuel
mixture is rich or lean by detecting the concentration of oxygen present in the exhaust gas.
Code No.
Diagnosis
Trouble Area
•
Engine ground bolt loose
•
Open in E1 circuit
(1) Oxygen sensor output is less than 0.45 V
O en in E1 circuit
•
Open in injector circuit
( )
yg
for at least 90 sec. When oxygen sensor is
O en in injector circuit
•
Fuel line pressure (Injector blockage, etc.)
yg
warmed up (racing at 2,000 rpm).
Fuel line ressure (Injector blockage, etc.)
•
Open or short in oxygen sensor circuit
25
O en or short in oxygen sensor circuit
•
Oxygen sensor
•
Ignition system
*
1
(2) When air–fuel ratio feed–back correction
•
Ignition system
•
Water temp. sensor
Ai fl
( i i
k )
(2) When air–fuel ratio feed–back correction
value or adaptive control value continues
•
Air flow meter (air intake)
•
Foreign object caught in valve
value or ada tive control value continues
at the upper (lean) or lower (rich) limit for a
t i
i d f ti
d
ti
t l
•
Foreign object caught in valve
•
ECU
certain period of time or adaptive control
value is not renewed for a certain period of
ECU
value is not renewed for a certain eriod of
time.
•
Engine ground bolt loose
•
Open in E1 circuit
Sh t i i j
t
i
it
•
Short in injector circuit
•
Fuel line pressure (Injector leakage, etc.)
*
1
•
Fuel line ressure (Injector leakage, etc.)
•
Open or short in cold start injector circuit
(3) When marked variation is detected in en-
•
O en or short in cold start injector circuit
•
Cold start injector
26
( )
gine revolutions for each cylinder during
•
Cold start injector
•
Open or short in oxygen sensor circuit
26
g
y
g
idle switch on and feedback condition.
•
O en or short in oxygen sensor circuit
•
Oxygen sensor
•
Oxygen sensor
•
Water temp. sensor
•
Air flow meter
•
Air flow meter
•
Compression pressure
•
Foreign object caught in valve
•
ECU
(2 trip detection logic)*
•
ECU
*: See page
*
1
: No. (2) and (3) in the diagnostic contents of codes No. 25 and 26 apply to California
specification vehicles only, while (1) applies to all models.
TR–44
–
ENGINE TROUBLESHOOTING
Circuit Inspection
Summary of Contents for 2VZ-FE
Page 1: ...ENGINE MECHANICAL EM 1 ENGINE MECHANICAL Description Operation ...
Page 31: ...CYLINDER HEADS COMPONENTS EM 29 ENGINE MECHANICAL Cylinder Heads ...
Page 63: ...CYLINDER BLOCK REMOVAL OF ENGINE EM 61 ENGINE MECHANICAL Cylinder Block ...
Page 64: ...EM 62 ENGINE MECHANICAL Cylinder Block ...
Page 71: ...COMPONENTS EM 69 ENGINE MECHANICAL Cylinder Block ...
Page 106: ...EFI SYSTEM FI 1 ...
Page 107: ...DESCRIPTION FI 2 EFI SYSTEM Description ...
Page 111: ...OPERATION System Circuit FI 4 EFI SYSTEM Operation System Circuit ...
Page 121: ...FUEL SYSTEM Fuel Pump EFI SYSTEM Fuel System Fuel Pump FI 15 ...
Page 141: ...Fuel Tank and Lines COMPONENTS EFI SYSTEM Fuel System Fuel Tank and Lines FI 35 ...
Page 172: ...EXHAUST SYSTEM EXHAUST SYSTEM REPAIR INSTRUCTIONS EX 1 ...
Page 174: ...EMISSION CONTROL SYSTEMS EC 1 ...
Page 186: ...COOLING SYSTEM CO 1 ...
Page 205: ...LUBRICATION SYSTEM LUBRICATION SYSTEM Description Operation LU 1 ...
Page 224: ...IGNITION SYSTEM IG 1 ...
Page 237: ...SERVICE SPECIFICATIONS IG 14 IGNITION SYSTEM ServiceSpecifications ...
Page 238: ...ENGINE TROUBLESHOOTING TR 1 ...