1986 TOYOTA LAND CRUISER ignition

+25 %
-12.5 %
More than 0.5 V
Less than 0.4 V
Case 1
Case 2
Case 3
Case 4
Output voltage of heated oxygen
sensor (sensor 1: front sensor)
Injection volume
Output voltage
Output voltage of heated oxygen
sensor (sensor 2: rear sensor)Mainly suspect
trouble area
OK
+25 %
-12.5 %
More than 0.5 V
Less than 0.4 V
Injection volume
Output voltage
+25 %
-12.5 %
More than 0.5 V
Less than 0.4 V
Injection volume
Output voltage
Sensor 1: front sensor
(sensor 1, heater, sensor 1
circuit)
+25 %
-12.5 %
More than 0.5 V
Less than 0.4 V
Injection volume
Output voltage
+25 %
-12.5 %
Injection volume
Output voltage
NG
+25 %
-12.5 %
Injection volume
Output voltage
NG
+25 %
-12.5 %
Injection volume
Output voltage
NG
+25 %
-12.5 %
Injection volume
Output voltage
NGExtremely rich or lean of the
actual air-fuel ratio
(Injector, fuel pressure, gas
leakage in exhaust system,
etc.) OK
OK
OK
Almost no reaction
'
Sensor 2: rear sensor
(sensor 2, heater, sensor 2
circuit)
Almost no reactionAlmost no reaction
Almost no reaction
DI-142
- DIAGNOSTICSENGINE
335 Author
: Date
:
2004 LAND CRUISER (RM1071U)
INSPECTION PROCEDURE
HINT:
Hand-held tester only:
The narrowing down the trouble area is possible by performing ACTIVE TEST of the following ºA/F CON-
TROLº (Heated oxygen sensor or another can be distinguished).
(a) Perform ACTIVE TEST by hand-held tester (A/F CONTROL).
HINT:
ºA/F CONTROLº is the ACTIVE TEST which changes the injection volume to -12.5 % or +25 %.
(1) Connect the hand-held tester to the DLC3 on the vehicle.
(2) Turn the ignition switch ON.
(3) Warm up the engine with the engine speed at 2,500 rpm for approximately 90 seconds.
(4) Select the item ºDIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROLº.
(5) Perform ºA/F CONTROLº with the engine in an idle condition (press the right or left button).
RESULT:
Heated oxygen sensor reacts in accordance with increase and decrease of injection volume
+25 % " rich output: More than 0.5 V
-12.5 % " lean output: Less than 0.4 V
NOTICE:
However, there is a few seconds delay in the sensor 1 (front sensor) output. And there is about 20
seconds delay in the sensor 2 (rear sensor).

- DIAGNOSTICSENGINE
DI-143
336 Author
: Date
:
2004 LAND CRUISER (RM1071U)
The following A/F CONTROL procedure enables the technician to check and graph the voltage output of
the heated oxygen sensors.
For displaying the graph indication, first enter ºACTIVE TEST / A/F CONTROL / USER DATA,º then select
º02S B1S1and O2S B1S2º by pressing ºYESº button, and push ºENTERº button before pressing ºF4º button.
HINT:
If different DTCs that are related to different system are output simultaneously while terminal E2 is used
as a ground terminal, terminal E2 may be open.
Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records
the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determin-
ing whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio
was lean or rich, etc. at the time of the malfunction.
1 Are there any other codes (besides DTC P0136 or P0156) being output?
PREPARATION:
(a) Connect the hand-held tester or the OBD II scan tool to the DLC3.
(b) Turn the ignition switch ON and push the hand-held tester or OBD II scan tool main switch ON.
(c) When using hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC
INFO / CURRENT CODES.
CHECK:
Read the DTC using the hand-held tester or the OBD ll scan tool.
RESULT:
Display (DTC Output)Proceed to
P0136A
ºP0136º and other DTCsB
HINT:
If any other codes besides P0136 are output, perform the troubleshooting for those DTCs first.
B Go to relevant DTC chart (See page DI-36).
A

- DIAGNOSTICSENGINE
DI-147
340 Author
: Date
:
2004 LAND CRUISER (RM1071U)
DTC P0171 System too Lean (Bank 1)
DTC P0172 System too Rich (Bank 1)
DTC P0174 System too Lean (Bank 2)
DTC P0175 System too Rich (Bank 2)
CIRCUIT DESCRIPTION
The fuel trim is related to the feedback compensation value, not to the basic injection time. The fuel trim in-
cludes the short-term fuel trim and the long-term fuel trim.
The short-term fuel trim is the short-term fuel compensation used to maintain the air-fuel ratio at stoichio-
metric air-fuel ratio. The signal from the heated oxygen sensor indicates whether the air-fuel ratio is RICH
or LEAN compared to the stoichiometric air-fuel ratio. This variance triggers a reduction in the fuel volume
if the air-fuel ratio is RICH, and an increase in the fuel volume if it is LEAN.
The long-term fuel trim is the overall fuel compensation carried out in long-term to compensate for a continu-
al deviation of the short-term fuel trim from the central value, due to individual engine differences, wear over-
time and changes in the operating environment.
If both the short-term fuel trim and the long-term fuel trim are LEAN or RICH beyond a certain value, it is
detected as a malfunction and the MIL is illuminated and a DTC is set.
DTC No.DTC Detecting ConditionTrouble Area
P0171
P0174When air-fuel ratio feedback is stable after warming up engine,
fuel trim is considerably in error on LEAN side
(2 trip detection logic)
Air induction system
Injector blockage
Mass air flow meter
Engine coolant temperature sensor
Fuel pressure
Gas leakage in exhaust system
Open or short in heated oxygen sensor (bank 1, 2 sensor 1)
circuit
Heated oxygen sensor (bank 1, 2 sensor 1)
Heated oxygen sensor heater (bank 1, 2 sensor 1)
EFI or ECD relay
PCV piping
ECM
P0172
P0175When air-fuel ratio feedback is stable after warming up engine,
fuel trim is considerably in error on RICH side
(2 trip detection logic)
Injector leak, blockage
Mass air flow meter
Engine coolant temperature sensor
Ignition system
Fuel pressure
Gas leakage in exhaust system
Open or short in heated oxygen sensor (bank 1, 2 sensor 1)
circuit
Heated oxygen sensor (bank 1, 2 sensor 1)
ECM
DIC2A-01

+25 %
-12.5 %
More than 0.5 V
Less than 0.4 V
Case 1
Case 2
Case 3
Case 4
Output voltage of heated oxygen
sensor (sensor 1: front sensor)
Injection volume
Output voltage
Output voltage of heated oxygen
sensor (sensor 2: rear sensor)Mainly suspect
trouble area
OK
+25 %
-12.5 %
More than 0.5 V
Less than 0.4 V
Injection volume
Output voltage
+25 %
-12.5 %
More than 0.5 V
Less than 0.4 V
Injection volume
Output voltage
Sensor 1: front sensor
(sensor 1, heater, sensor 1
circuit)
+25 %
-12.5 %
More than 0.5 V
Less than 0.4 V
Injection volume
Output voltage
+25 %
-12.5 %
Injection volume
Output voltage
NG
+25 %
-12.5 %
Injection volume
Output voltage
NG
+25 %
-12.5 %
Injection volume
Output voltage
NG
+25 %
-12.5 %
Injection volume
Output voltage
NGExtremely rich or lean of the
actual air-fuel ratio
(Injector, fuel pressure, gas
leakage in exhaust system,
etc.) OK
OK
OK
Almost no reaction
'
Sensor 2: rear sensor
(sensor 2, heater, sensor 2
circuit)
Almost no reactionAlmost no reaction
Almost no reaction
DI-150
- DIAGNOSTICSENGINE
343 Author
: Date
:
2004 LAND CRUISER (RM1071U)
INSPECTION PROCEDURE
HINT:
Hand-held tester only:
The narrowing down the trouble area is possible by performing ACTIVE TEST of the following ºA/F CON-
TROLº (Heated oxygen sensor or another can be distinguished).
(a) Perform ACTIVE TEST by hand-held tester (A/F CONTROL).
HINT:
ºA/F CONTROLº is the ACTIVE TEST which changes the injection volume to -12.5 % or +25 %.
(1) Connect the hand-held tester to the DLC3 on the vehicle.
(2) Turn the ignition switch ON.
(3) Warm up the engine with the engine speed at 2,500 rpm for approximately 90 seconds.
(4) Select the item ºDIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROLº.
(5) Perform ºA/F CONTROLº with the engine in an idle condition (press the right or left button).
RESULT:
Heated oxygen sensor reacts in accordance with increase and decrease of injection volume
+25 % " rich output: More than 0.5 V
-12.5 % " lean output: Less than 0.4 V
NOTICE:
However, there is a few seconds delay in the sensor 1 (front sensor) output. And there is about 20
seconds delay in the sensor 2 (rear sensor).

S01196S01699
30
20
10
5
3
02040 0.11
0.3
0.2 0.52
60 80 100 -20
(-4) (104) (140) (176)(32) (68) (212)
A21042
Ohmmeter
Acceptable
TEMPERATURE C (F)
RESISTANCE KW
- DIAGNOSTICSENGINE
DI-153
346 Author
: Date
:
2004 LAND CRUISER (RM1071U)
5 Check engine coolant temperature sensor.
PREPARATION:
Remove the engine coolant temperature sensor.
CHECK:
(a) Measure the resistance between the terminals of the en-
gine coolant temperature sensor.
Resistance:
Tester ConnectionSpecified Condition
122.32 to 2.59 kW (20C (68F))1 - 20.310 to 0.326 kW (80C (176F))
NOTICE:
In case of checking the engine coolant temperature sensor
in the water, be careful not to allow water to go into the ter-
minals. After checking, dry the sensor.
HINT:
Alternate procedure: Connect an ohmmeter to the installed en-
gine coolant temperature sensor and read the resistance. Use
an infrared thermometer to measure the engine temperature in
the immediate vicinity of the sensor. Compare these values to
the resistance/temperature graph. Change the engine temper-
ature (warm up or allow to cool down) and repeat the test.
(b) Reinstall the engine coolant temperature sensor.
NG Repair or replace engine coolant temperature
sensor.
OK
6 Check for spark and ignition (See page IG-1).
NG Repair or replace ignition system.
OK

A09299A21418
Vehicle speed
(30 km/h)19 mph
IG SW OFF
Warm up
2 minutes 2 minutes 2 minutes
(
1)(
3)
(
4)
Idling(
2)(
3)
(
4)(
3) 3 to 5 minutes 3 to 5 minutes 3 to 5 minutes
(
4)
- DIAGNOSTICSENGINE
DI-159
352 Author
: Date
:
2004 LAND CRUISER (RM1071U)
14 Perform confirmation driving pattern.
(a) Disconnect the battery terminal and wait for a minute (clear learning value of the air fuel ratio). (
1)
(b) Connect the hand-held tester to the DLC3. (
1)
(c) Switch the hand-held tester from the normal mode to the check mode (See page DI-3). (
1)
(d) Start the engine and let it idle until engine coolant temperature is 75 °C (167 °F ) or more. (
2)
(e) Drive the vehicle at 19 mph (30 km/h) or more for 3 minutes or more. (
3)
(f) Let the engine idle for approx. 2 minutes. (
4)
(g) Perform steps (e) and (g) at least 3 times.
HINT:
If a malfunction exists, the MIL will be illuminated during step (f).
NOTICE:
If the conditions in this test are not strictly followed, detecting a malfunction may be difficult. If you
do not have a hand-held tester, turn the ignition switch OFF after performing steps (e) to (f), and then
do step (f) again.
GO
15 Is there DTC P0171, P0172, P0174 or P0175 being output again?
YES Replace ECM (See page SF-60) and perform
confirmation driving pattern (Refer to step 14).
NO

A21043
Starter Relay EFI Relay
Circuit Opening
Relay
Fuel Pump RelayMREL
FPRTr2
Tr1 EFI
IGNECM
FC
NE Fuel Pump
Battery
StarterFuel Pump Resistor
AM2Ignition Switch
STA
Crankshaft Position
Sensor (NE Signal) DI-162
- DIAGNOSTICSENGINE
355 Author
: Date
:
2004 LAND CRUISER (RM1071U)
DTC P0230 Fuel Pump Primary Circuit
CIRCUIT DESCRIPTION
In the diagram below, when the engine is cranked, current flows from terminal STAR of the ECM to the starter
relay coil and also current flows to terminal STA of the ECM (STA signal).
When the STA signal and NE signal are input to the ECM, the Tr1 is turned ON, current flows to the coil of
the circuit opening relay, the relay switches on, power is supplied to the fuel pump, and the fuel pump oper-
ates.
While the NE signal is generated (engine running), the ECM keeps the Tr1 ON (circuit opening relay ON)
and the fuel pump also keeps operating.
The fuel pump speed is controlled at two levels (high speed or low speed) by the condition of the engine
(starting, light load, heavy load). When the engine starts (STA ON), the Tr2 in the ECM is OFF, so the fuel
pump relay closes and battery positive voltage is applied directly to the fuel pump. The fuel pump operates
at high speed.
After the engine starts during idling or light loads, since the Tr2 goes ON, power is supplied to the fuel pump
via the fuel pump resistor. The fuel pump operates at low speed.
DIC2B-01

A19965A20085
ECM
FPR
FC
MREL Engine Room R/B
Engine Room J/B
Cowl Side J/B RH Cowl Side J/B LH
I18
Ignition SW
Cowl Side J/B LHJ/B No. 5
J4
J/C
MAINJ/B No. 6
F15
FL Block Fuel Pump
Relay
C/OPN Relay
EFI or ECD Relay
EFI or ECD No. 1
AM2
IGN
Battery 1
1
1
1
1
111 1 1 1 1 1
1 2 35 4
3
125
1
2 3
4 R-L
R-L
R-LB
BB
IA29
BB1
2
G-W6D
6C710
G-W
B-Y
B-Y
W-BG-W
B-W
B-WF12
Fuel
Pump
1
4
2 16
13
155C 5D
5C 5D
5C 5D B-R
B-Y
B-W
B-YM4
5 B
W-B33
E5
10
8 E9
E9
BB1 8
W-B 1A
1B
1B
1B 1C1 9 11 44 43
422
3E3B
AA B-R
B-RB-R
6 7
2K 2A 2E W-R W-R
B-G
W-B
33
IF EAB-W
B-W
F14 Fuel Pump
Resistor
L-B
4110
2 IG2 AM2If113
G-WG-W 12
DI-164
- DIAGNOSTICSENGINE
357 Author
: Date
:
2004 LAND CRUISER (RM1071U)
WIRING DIAGRAM
HINT:
This diagnostic chart is based on premise that engine is started. If the engine is not started, proceed to prob-
lem symptoms table on DI-48.