p0402 TOYOTA LAND CRUISER 1996 J80 Workshop Manual

N09214
DI−4
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DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
The diagnosis system operates in normal mode
during normal vehicle use. It also has a check mode
for technicians to simulate malfunction symptoms
and troubleshoot. Most DTC use 2 trip detection
logic* to prevent erroneous detection, and ensure
thorough malfunction detection. By switching the
ECM to check mode when troubleshooting, the
technician can cause the MIL to light up for a mal-
function that is only detected once or momentarily
(TOYOTA hand−held tester only) (See step 2).
*2 trip detection logic:
When a logic malfunction is first detected, the mal-
function is temporarily stored in the ECM memory.
If the same malfunction is detected again during the
second drive test, this second detection causes the
MIL to light up.
The 2 trip repeats the same mode a 2nd time (How-
ever, the IG switch must be turned OFF between the
1st trip and 2nd trip.).
Freeze frame data:
Freeze frame data records the engine condition
when a misfire (DTC P0300 − P0306) or fuel trim
malfunction (DTC P0171, P0172) or other malfunc-
tion (first malfunction only), is detected.
Because freeze frame data records the engine
conditions (fuel system, calculator load, engine
coolant temperature, fuel trim, engine speed, ve-
hicle speed, etc.) when the malfunction is detected,
when troubleshooting it is useful for determining
whether the vehicle was running or stopped, the en-
gine warmed up or not, the air− fuel ratio lean or rich,
etc. at the time of the malfunction.
Priorities for troubleshooting:
If troubleshooting priorities for multiple DTCs are given in the
applicable diagnostic chart, these should be followed.
If no instructions are given troubleshoot DTCs according to the
following priorities. (1) DTC other than fuel trim malfunction (DTC P0171,
P0172), EGR (DTC P0401, P0402), and misfire
(DTC P0300 − P0306).
(2) Fuel trim malfunction (DTC P0171, P0172), and EGR (DTC P0401, P0402).
(3) Misfire (DTC P0300 − P0306).
(b) Check the DLC3. The vehicle’s ECM uses V.P.W. (V ariable Pulse Width) for
communication to comply with SAE J1850. The terminal
arrangement of DLC3 complies with SAE J1962 and
matches the V.P.W. format.
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DI−14
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DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
DTC No.
(See Page)
Detection ItemTrouble AreaMILMemory
P0171
( DI−51 )System too Lean
(Fuel T rim)
Air intake (hose loose)
 Fuel line pressure, leak
 Injector blockage
 Heated oxygen sensor malfunction
 Mass air flow meter
 Engine coolant temp. sensor
 *1
P0172
( DI−51 )System too Rich
(Fuel T rim)
Fuel line pressure
 Injector leak, blockage
 Heated oxygen sensor malfunction
 Mass air flow meter
 Engine coolant temp. sensor
 *1
P0300
( DI−54 )Random/Multiple Cylinder
Misfire DetectedIgnition system
 Injector
 Fuel line pressure
 EGR
 Compression pressure
 Valve clearance not to specification
 Valve timing
 Mass air flow meter
 Engine coolant temp. sensor
 *2
P0301
P0302
P0303
P0304
P0305
P0306
( DI−54 )Misfire Detected
− Cylinder 1
− Cylinder 2
− Cylinder 3
− Cylinder 4
− Cylinder 5
− Cylinder 6
P0325
( DI−59 )Knock Sensor 1 Circuit
MalfunctionOpen or short in knock sensor 1 circuit
 Knock sensor 1 (looseness)
 ECM
 *1
P0330
( DI−59 )Knock Sensor 2 Circuit
MalfunctionOpen or short in knock sensor 2 circuit
 Knock sensor 2 (looseness)
 ECM
 *1
P0335
( DI−62 )Crankshaft Position Sensor
”A” Circuit Malfunction
Open or short in crankshaft position sensor circuit for NE sig-
nal
 Crankshaft position sensor for NE signal
 Starter
 ECM
 *1
P0340
( DI−65 )Camshaft Position Sensor
Circuit MalfunctionOpen or short in camshaft position sensor circuit
 Camshaft position sensor
 ECM
 *1
P0385
( DI−67 )Crankshaft Position Sensor
”B” Circuit Malfunction
Open or short in crankshaft position sensor circuit for NE2
signal
 Crankshaft position sensor for NE2 signal
 ECM
 *1
P0401
( DI−69 )Exhaust Gas Recirculation
Flow Insufficient Detected
EGR valve stuck closed
 Short in VSV circuit for EGR
 Open in EGR gas temp. sensor circuit
 EGR hose disconnected
 ECM
 *1
P0402
( DI−80 )Exhaust Gas Recirculation
Flow Excessive Detected
EGR valve stuck open
 EGR VSV open malfunction
 Open in VSV circuit for EGR
 Short in EGR gas temp. sensor circuit
 ECM
 *1
*1: MIL lights up
*2: MIL lights up or blinking
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DI−80
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
DTC P0402 Exhaust Gas Recirculation Flow Excessive Detected
CIRCUIT DESCRIPTION
Refer to DTC P0401 (Exhaust Gas Recirculation Flow Insufficient Detected) on page DI−69.
DTC No.DTC Detecting ConditionTrouble Area
P0402
EGR gas temp. sensor value is high during EGR cut −off when
engine is cold (Race engine at about 4,000 rpm without load so
that vacuum is applied to port E)
(2 trip detection logic) EGR valve stuck open
 EGR VSV open malfunction
 Open in VSV circuit for EGR
 Short in EGR gas temp. sensor circuit
 ECM
EGR valve is always open (2 trip detection logic)
Refer to DTC P0401 (Exhaust Gas Recirculation Flow Insufficient Detected) for the System Check Driving
Pattern and Wiring Diagram.
INSPECTION PROCEDURE
TOYOTA hand −held tester
1 Connect the TOYOTA hand −held tester and read EGR gas temp. value.
PREPARATION:
(a) Remove the fuse cover on the instrument panel.
(b) Connect the TOYOTA hand−held tester to the DLC3.
(c) Turn ignition switch ON and push the TOYOTA hand −held tester main switch ON.
CHECK:
Read EGR gas temp. on the TOYOTA hand−held tester.
OK:
EGR gas temp.: 150° C (302°F) or less (Not immediately after driving)
HINT:
If there is a short circuit, the TOYOTA hand−held tester indicates Approx. 157.5°C (315.5°F).
OK Go to step 4.
NG
DI5PL−02
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