2001 TOYOTA SEQUOIA diagnostic menu

DI±170
± DIAGNOSTICSENGINE
364 Author: Date:
2005 SEQUOIA (RM1146U)
HINT:

Read freeze frame data using a hand±held tester. Freeze frame data record the engine condition when
malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle
was moving or stationary, if the engine was warmed up or not, if the air±fuel ratio was lean or rich, and
other data, from the time the malfunction occurred.

A low A/F sensor voltage could be caused by a rich air±fuel mixture. Check for conditions that would
cause the engine to run rich.

A high A/F sensor voltage could be caused by a lean air±fuel mixture. Check for conditions that would
cause the engine to run lean.
1 Check any other DTCs output (in addition to DTC P0171, P0172, P0174 or P0175).
PREPARATION:
(a) Connect a hand±held tester to the DLC3.
(b) Turn the ignition switch to ON and turn the tester ON.
(c) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
CHECK:
(a) Read DTCs.
Result:
Display (DTC Output)Proceed To
P0171, P0172, P0174 or P0175A
P0171, P0172, P0174 or P0175 and other DTCsB
HINT:
If any DTCs other than P0171, P0172, P0174 or P0175 are output, troubleshoot those DTCs first.
B Go to DTC chart (See page DI±58).
A
2 Check connection of PCV piping.
OK:
PCV hose is connected correctly and is not damaged.
NG Repair or replace PCV piping.
OK

± DIAGNOSTICSENGINE
DI±171
365 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check air induction system (See page SF±1).
CHECK:
Check the air induction system for vacuum leaks.
NG Repair or replace air induction system.
OK
4 Perform active test (A/F control).
(a) Connect the hand±held tester to the DLC3.
(b) Start the engine and turn the tester ON.
(c) Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
(d) On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST /
A/F CONTROL.
(e) Perform the A/F CONTROL operation with the engine in an idling condition (press the RIGHT or LEFT
button to change the fuel injection volume).
(f) Monitor the voltage outputs of A/F and HO2 sensors(AFS B1S1 (AFS B2S1) and O2S B1S2 (O2S
B2S2)) displayed on the tester.
HINT:

The A/F CONTROL operation lowers the fuel injection volume by 12.5 % or increases the injection
volume by 25 %.

Each sensor reacts in accordance with increases and decreases in the fuel injection volume.
Standard:
Tester Display
(Sensor)Injection VolumesStatusVoltages
AFS B1S1 (AFS B2S1)
(A/F)+25 %RichLess than 3.0
AFS B1S1 (AFS B2S1)
(A/F)±12.5 %LeanMore than 3.35
O2S B1S2 (O2S B2S2)
(HO2)+25 %RichMore than 0.55
O2S B1S2 (O2S B2S2)
(HO2)±12.5 %LeanLess than 0.4
Result:
Status
AFS B1S1
(AFS B2S1)Status
O2S B1S2
(O2S B2S2)A/F Condition and
A/F Sensor ConditionMisfiresSuspected Trouble AreasProceed To
Lean/RichLean/RichNormal''C
LeanLeanActual air±fuel ratio leanMay occur

PCV valve and hose

PCV hose connections

Injector blockage

Gas leakage from exhaust system

Air induction system

Fuel pressure

Mass Air Flow (MAF) meter

Engine Coolant Temperature (ECT)
sensor
A

DI±172
± DIAGNOSTICSENGINE
366 Author: Date:
2005 SEQUOIA (RM1146U)Rich
RichActual air±fuel ratio rich'

Injector leakage or blockage

Gas leakage from exhaust system

Ignition system

Fuel pressure

MAF meter

ECT sensor
A
LeanLean/RichA/F sensor malfunction'
A/F sensorB
RichLean/RichA/F sensor malfunction'
A/F sensorB
Lean: During A/F CONTROL, the A/F sensor output voltage (AFS) is consistently more than 3.35 V, and the
HO2 sensor output voltage (O2S) is consistently less than 0.4 V.
Rich: During A/F CONTROL, the AFS is consistently less than 3.0 V, and the O2S is consistently more than
0.55 V.
B Go to step 11.
C Go to step 15.
A
5 Read value of engine coolant temperature.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch to ON and turn the tester ON.
(c) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / COOLANT
TEMP.
CHECK:
(a) Read the COOLANT TEMP twice, when the engine is cold and also when warmed up.
Standard:
With cold engine: Same as ambient air temperature.
With warm engine: Between 75C and 95C (167F and 203F)
NG Replace engine coolant temperature sensor.
OK

± DIAGNOSTICSENGINE
DI±173
367 Author: Date:
2005 SEQUOIA (RM1146U)
6 Read value of mass air flow meter.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch to ON and turn the tester ON.
(c) Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / MAF and
COOLANT TEMP.
(d) Allow the engine to idle until the COOLANT TEMP reaches 75C (167F) or more.
CHECK:
(a) Read the MAF with the engine in an idling condition and at an engine speed of 2,500 rpm.
Standard:
MAF while engine idling: Between 1.4 gm/s and 2.3 gm/s (shift position: N, A/C: OFF).
MAF at engine speed of 2,500 rpm: Between 5.4 gm/s and 7.9 gm/s (shift position: N, A/C: OFF).
NG Replace mass air flow meter.
OK
7 Check fuel pressure (See page SF±7).
CHECK:
Check the fuel pressure (high or low pressure).
NG Check and replace fuel pump, pressure regula-
tor, fuel pipe line and filter (See page SF±1).
OK
8 Check exhaust system for gas leakage.
OK:
No exhaust gas leakage.
NG Repair or replace exhaust gas leakage point.
OK

B17396
HT +B
AF± AF+ Sensor 1A/F Sensor Component Side:
Front View
DI±174
± DIAGNOSTICSENGINE
368 Author: Date:
2005 SEQUOIA (RM1146U)
9 Check for spark and ignition (See page IG±1).
HINT:
If the spark plugs or ignition system malfunction, engine misfire may occur. The misfire counter can be read
with the hand±held tester. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / MIS-
FIRE / CYL#1 (to CYL#8).
NG Repair or replace ignition system.
OK
10 Check injector injection (See page SF±29).
HINT:
If the injectors malfunction, engine misfires may occur. The misfire counter can be read with the hand±held
tester. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / MISFIRE / CYL#1 (to
CYL#8).
NG Replace injector.
OK
11 Check resistance of air±fuel ratio (A/F) sensor heater.
PREPARATION:
Disconnect the air±fuel ratio (A/F) sensor connector.
CHECK:
Measure resistance between the terminals of the A/F sensor
connector.
OK:
Standard:
Tester ConnectionSpecified Condition
HT (1) ± +B (2)1.8 to 3.4 W at 20C (68F)
HT (1) ± AF± (4)10 kW or higher
NG Replace air±fuel ratio (A/F) sensor.
OK

B17397
Vehicle Speed
Between
38 mph and 75 mph
(60 km/h and 120 km/h)
Idling
Ignition Switch OFF
3 to 5 minutes
Time 2 minutes
(a), (b), (c)(e)
(d)
± DIAGNOSTICSENGINE
DI±177
371 Author: Date:
2005 SEQUOIA (RM1146U)
15 Perform confirmation driving pattern.
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch to ON and turn the tester ON.
(c) Clear DTCs (see page DI±43).
(d) Switch the ECM from normal mode to check mode using the tester (see page DI±44).
(e) Start the engine and warm it up with all the accessories switched OFF.
(f) Drive the vehicle at between 38 mph and 75 mph (60 km/h and 120 km/h) and at an engine speed of
between 1,400 rpm and 3,200 rpm for 3 to 5 minutes.
HINT:
If the system is still malfunctioning, the MIL will be illuminated during step (e).
NOTICE:
If the conditions in this test are not strictly followed, no malfunction will be detected.
NEXT
16 Check whether DTC output recurs (DTC P0171, P0172, P0174 or P0175)
CHECK:
(a) On the hand±held tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC
INFO / PENDING CODES.
(b) Read DTCs.
RESULT:
Display (DTC Output)Proceed To
P0171, P0172, P0174 or P0175A
No outputB
B Go to step 5.
A

DI±192
± DIAGNOSTICSENGINE
386 Author: Date:
2005 SEQUOIA (RM1146U)
1 Are there any other codes (besides DTC P0300, P0301, P0302, P0303, P0304
P0305, P0306, P0307 or P0308) being output?
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 DTCs using hand±held tester.
RESULT:
Display (DTC Output)Proceed to
ºP0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and/or
P0308ºA
ºP0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or
P0308º and other DTCsB
HINT:
If any other codes besides ºP0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308º are
output, perform the troubleshooting for those DTCs.
B Go to relevant DTC chart (See page DI±58).
A
2 Check wire harness, connector and vacuum hose in engine room.
CHECK:
(a) Check the connection conditions of the wire harness and connector.
(b) Check for the disconnection, piping and brake of the vacuum hose.
NG Repair or replace, then confirm that there is no
misfire (See confirmation driving pattern).
OK

± DIAGNOSTICSENGINE
DI±193
387 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check connection of PCV piping.
OK:
PCV hose is connected correctly and is not damaged.
NG Repair or replace PCV piping.
OK
4 Connect hand±held tester, and read the number of misfire.
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) Start the engine.
(d) When using hand±held tester, enter the following menu: DIAGNOSIS / ENHANCED OBD II / DATA
LIST / ALL / CYL#1 to CYL#8.
CHECK:
Read the number of misfire on the hand±held tester.
HINT:
When a misfire is not reproduced, be sure to branch below based on the stored DTC.
RESULT:
High Misfire Rate CylinderProceed to
1 or 2 cylindersA
More than 3 cylindersB
B Go to step 15.
A