Toyota Sequoia (2005). Manual — part 88
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DIAGNOSTICS
ENGINE
DI–155
349
INSPECTION PROCEDURE
HINT:
Hand–held tester only:
Narrowing down the trouble area is possible by performing ACTIVE TEST of the following ”A/F CONTROL”
(Heated oxygen sensor or another can be distinguished).
(a)
Perform ACTIVE TEST by hand–held tester (A/F CONTROL).
HINT:
”A/F CONTROL” 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 menu ”DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL”.
(5)
Perform ”A/F CONTROL” 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:
There is a few seconds delay in the sensor 1 (front sensor) output. And there is approximately 20
seconds delay in the sensor 2 (rear sensor).
+25 %
–12.5 %
More than 0.5 V
Less than 0.4 V
Case 1
Case 2
Case 3
Case 4
Output voltage of A/F sensor
(sensor 1: front sensor)
Injection volume
Output voltage
Output voltage of heated oxygen
sensor (sensor 2: rear sensor)
Mainly suspected
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
NG
Extremely rich or lean 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 reaction
Almost
no reaction
Almost
no reaction
DI–156
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DIAGNOSTICS
ENGINE
350
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 ”ACTIVE TEST / A/F CONTROL / USER DATA,” then select
”A/F B1,2S1and O2S B1,2S2” by pressing ”YES” button, and push ”ENTER” button before pressing ”F4”
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
. Freeze frame data records the engine conditions
when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle
was running or stopped, the engine was warmed up or not, the air–fuel ratio was lean or rich, etc. when
a malfunction occurred.
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DIAGNOSTICS
ENGINE
DI–157
351
1
Read output DTC.
PREPARATION:
(a)
Connect the hand–held tester to the DLC3.
(b)
Turn the ignition switch ON and push the hand–held tester main switch ON.
(c)
When using hand–held tester, enter the following menu: DIAGNOSIS / ENHANCED OBD II / DTC
INFO / CURRENT CODES.
CHECK:
Read the DTC using the hand–held tester.
RESULT:
Display (DTC Output)
Proceed to
P0138, P0158
A
P0137, P0157
B
P0136, P0156
C
HINT:
If any other codes besides P0136, P0137, P0138, P0156, P0157 and/or P0158 are output, perform the trou-
bleshooting for those DTCs first.
B
Go to step 14.
C
Go to step 7.
A
2
Check output voltage of heated oxygen sensor.
PREPARATION:
(a)
Connect the hand–held tester to the DLC3.
(b)
After warming up the engine, run the engine at 2,500 rpm for 3 minutes.
(c)
When using hand–held tester, enter the following menu: DIAGNOSIS / ENHANCED OBD II / DATA
LIST / ALL / O2S B1S2 or B2S2.
(d)
Allow the engine to idle.
CHECK:
Read the Heated Oxygen (HO2) sensor output voltage while idling.
RESULT:
HO2 Sensor Output Voltages
Proceed To
More than 1.2 V
A
Less than 1.0 V
B
B
Go to step 5.
A
B17416
HT1B
ECM Connector
E7
OX1B
E8
HT2B
OX2B
A21341
+B
OX
E1
HT
H2
H4
Components Side:
Bank 1 Sensor 2, Bank 2 Sensor 2
DI–158
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DIAGNOSTICS
ENGINE
352
3
Check for short in harness and connector between terminal OX1B and HT1B,
OX2B and HT2B of ECM.
PREPARATION:
(a)
Turn the ignition switch to OFF and wait for 5 minutes.
(b)
Disconnect the E7 and E8 ECM connector.
CHECK:
(a)
Check the resistance.
OK:
Standard:
Tester Connections
Specified Conditions
HT1B (E8–1) – OX1B (E8–18)
10 k
Ω
or higher
HT2B (E7–5) – OX2B (E5–33)
10 k
Ω
or higher
OK
Replace ECM (See page
NG
4
Check resistance of heated oxygen sensor heater.
PREPARATION:
Disconnect the heated oxygen sensor connector.
CHECK:
Measure resistance between terminals of the heated oxygen
sensor.
OK:
Standard:
Tester Connection
Specified Condition
HT (1) – +B (2)
11 to 16
Ω
at 20
°
C (68
°
F)
+B (2) – OX (3)
10 k
Ω
or higher
NG
Replace heated oxygen sensor.
OK
Repair or replace harness or connector.
5
Perform confirmation driving pattern.
NEXT
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