2001 TOYOTA SEQUOIA relay

A23547
2
A1A± MREL
HA2A
A1A+ECM
22
30 B±W
E4
E7
E7 E7
BR W±B
2EFI Relay
A39 A/F Sensor
(Bank 2 Sensor 1)
J42
J/C Engine Room R/B No. 2
W 114
F10
FL
Block
Battery
ED(Shielded)8
EB 3
2HT
AF+ +B
B
E77
E04 2IA4
5
L±R G±R
2
G±B
2
B 1
B1
4
BRB±W
W±B 2F
A/F 1
1 12 Engine Room R/B and J/B
2D
2A2H
26
EFI No. 1 EFI No. 2
22
W±BA/F Relay
1 2
3
5A
AJ2
J/C
G±R
15
IA51
IG4
(Shielded)
G
R
ECE
ECCC
J42
J/C J5
J/CJ2
J/C B
B 5Engine
Room
R/B No. 2R±W
R±W
R±W
R±W
A38 A/F Sensor
(Bank 1 Sensor 1)
+B AF±
HT
AF+
AF±1
3 2
4
1
3 2
4 R±WL31
E7 23
E7 E7
A2A+
A2A±
HA1A B
R/B
± DIAGNOSTICSENGINE
DI±389
583 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM

B17396
HT +B
AF± AF+ Sensor 1A/F Sensor Component Side:
Front View
A19288
A/F Relay
± DIAGNOSTICSENGINE
DI±397
591 Author: Date:
2005 SEQUOIA (RM1146U)
10 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:
Tester ConnectionSpecified Condition
HT (1) ± +B (2)Between 1.8 W and 3.4 W at 20C (68F)
HT (1) ± AF± (4)10 kW or higher
NG Replace air±fuel ratio (A/F) sensor.
OK
11 Check A/F relay.
PREPARATION:
Remove the A/F relay from the engine room J/B.
CHECK:
Inspect the A/F relay.
OK:
Standard:
Terminal No.ConditionSpecified Condition
3 ± 5Always10 KW or higher
3 ± 5Apply B+ between
terminals 1 and 2Below 1 W
NG Replace EFI relay.
OK

A23659
Wire Harness Side:
HT
A38
Sensor 1A/F Sensor Connector
AF+
Front ViewAF±
+B A39
B17415A55007
E7ECM Connector
HA1A
A1A+
A1A±
A2A+
A2A±HA2A
A23512
Reference (Bank 1 Sensor 1 System Drawing):
A/F Sensor A/F Relay
Heater
Sensor
A1A+ HA1A
Duty
Control ECM
From
Battery
A/F Heater
Fuse
A1A±
To EFI Relay DI±398
± DIAGNOSTICSENGINE
592 Author: Date:
2005 SEQUOIA (RM1146U)
12 Check for open and short in harness and connector between ECM and A/F sen-
sor.
PREPARATION:
(a) Disconnect the A38 or A39 A/F sensor connector.
(b) Turn the ignition switch to ON.
CHECK:
(a) Measure the voltage between the +B terminal of the A/F
sensor connector and body ground.
Standard:
Tester ConnectionsSpecified Conditions
+B (2) ± Body groundBetween 9 V and 14 V
PREPARATION:
(a) Turn the ignition switch to OFF.
(b) Disconnect the E7 ECM connector.
CHECK:
(a) Check the resistance.
Standard (Check for open):
Tester ConnectionsSpecified Conditions
HT (A38±1) ± HA1A (E7±2)
HT (A39±1) ± HA2A (E7±1)Below 1 W
AF+ (A38±3) ± A1A+ (E7±22)
AF+ (A39±3) ± A2A+ (E7±23)Below 1 W
AF± (A38±4) ± A1A± (E7±30)
AF± (A39±4) ± A2A± (E7±31)Below 1 W
Standard (Check for short):
Tester ConnectionsSpecified Conditions
HT (A38±1) or HA1A (E7±2) ± Body ground
HT (A39±1) or HA2A (E7±1) ± Body ground10 kW or higher
AF+ (A38±3) or A1A+ (E7±22) ± Body ground
AF+ (A39±3) or A2A+ (E7±23) ± Body ground10 kW or higher
AF± (A38±4) or A1A± (E7±30) ± Body ground
AF± (A39±4) or A2A± (E7±31) ± Body ground10 kW or higher

± DIAGNOSTICSENGINE
DI±403
597 Author: Date:
2005 SEQUOIA (RM1146U)
CIRCUIT DESCRIPTION
Refer to DTC P2195 on page DI±383.
DTC No.DTC Detection ConditionsTrouble Areas
P2238
P2241

Case 1:
Condition (a) or (b) continues for 5.0 seconds or more
(1 trip detection logic):
(a) AF+ voltage 0.5 V or less
(b) (AF+) ± (AF±) = 0.1 V or less

Case 2:
A/F sensor admittance: Less than 0.022 1/W
(1 trip detection logic)

Open or short in A/F sensor (sensor 1) circuit

A/F sensor (sensor 1)

A/F sensor heater

EFI relay

A/F sensor heater and relay circuits

ECM
P2239
P2242AF+ voltage more than 4.5 V for 5.0 seconds or more
(1 trip detection logic)

Open or short in A/F sensor (sensor 1) circuit

A/F sensor (sensor 1)

A/F sensor heater

EFI relay

A/F sensor heater and relay circuits

ECM
P2252
P2255AF± voltage 0.5 V or less for 5.0 seconds or more
(1 trip detection logic)

Open or short in A/F sensor (sensor 1) circuit

A/F sensor (sensor 1)

A/F sensor heater

EFI relay

A/F sensor heater and relay circuits

ECM
P2253
P2256AF± voltage more than 4.5 V for 5.0 seconds or more
(1 trip detection logic)

Open or short in A/F sensor (sensor 1) circuit

A/F sensor (sensor 1)

A/F sensor heater

EFI relay

A/F sensor heater and relay circuits

ECM
MONITOR DESCRIPTION
The Air±Fuel Ratio (A/F) sensor varies its output voltage in proportion to the air±fuel ratio. If the A/F sensor
impedance (alternating current resistance) or voltage output deviates greatly from the standard range, the
ECM determines that there is an open or short malfunction in the A/F sensor circuit.

B17396
HT +B
AF± AF+ Sensor 1A/F Sensor Component Side:
Front View
A19288
± DIAGNOSTICSENGINE
DI±407
601 Author: Date:
2005 SEQUOIA (RM1146U)
HINT:
Read freeze frame data using a hand±held tester. Freeze frame data record the engine condition when mal-
functions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was mov-
ing 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.
1 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:
Tester ConnectionSpecified Condition
HT (1) ± +B (2)Between 1.8 W and 3.4 W at 20C (68F)
HT (1) ± AF± (4)10 kW or higher
NG Replace air±fuel ratio (A/F) sensor.
OK
2 Check A/F relay.
PREPARATION:
Remove the A/F relay from the engine room J/B.
CHECK:
Inspect the A/F relay.
OK:
Terminal No.ConditionSpecified Condition
1 ± 2ConstantContinuity
UsuallyNo Continuity
3 ± 5Apply B+ between
terminals 1 and 2Continuity
NG Replace EFI relay.
OK

A23659
Wire Harness Side:
HT
A38
Sensor 1A/F Sensor Connector
AF+
Front ViewAF±
+B A39
B17415A55007
E7ECM Connector
HA1A
A1A+
A1A±
A2A+
A2A±HA2A
A23512
Reference (Bank 1 Sensor 1 System Drawing):
A/F Sensor A/F Relay
Heater
Sensor
A1A+ HA1A
Duty
Control ECM
From
Battery
A/F Heater
Fuse
A1A±
To EFI Relay DI±408
± DIAGNOSTICSENGINE
602 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check for open and short in harness and connector between ECM and A/F sen-
sor.
PREPARATION:
(a) Disconnect the A38 or A39 A/F sensor connector.
(b) Turn the ignition switch to ON.
CHECK:
(a) Measure the voltage between the +B terminal of the A/F
sensor connector and body ground.
OK:
Standard:
Tester ConnectionsSpecified Conditions
+B (2) ± Body groundBetween 9 V and 14 V
PREPARATION:
(a) Turn the ignition switch to OFF.
(b) Disconnect the E7 ECM connector.
CHECK:
(a) Check the resistance.
OK:
Standard (Check for open):
Tester ConnectionsSpecified Conditions
HT (A38±1) ± HA1A (E7±2)
HT (A39±1) ± HA2A (E7±1)Below 1 W
AF+ (A38±3) ± A1A+ (E7±22)
AF+ (A39±3) ± A2A+ (E7±23)Below 1 W
AF± (A38±4) ± A1A± (E7±30)
AF± (A39±4) ± A2A± (E7±31)Below 1 W
Standard (Check for short):
Tester ConnectionsSpecified Conditions
HT (A38±1) or HA1A (E7±2) ± Body ground
HT (A39±1) or HA2A (E7±1) ± Body ground10 kW or higher
AF+ (A38±3) or A1A+ (E7±22) ± Body ground
AF+ (A39±3) or A2A+ (E7±23) ± Body ground10 kW or higher
AF± (A38±4) or A1A± (E7±30) ± Body ground
AF± (A39±4) or A2A± (E7±31) ± Body ground10 kW or higher

A23667
Soak Timer Circuit
Ignition Switch
IGSW
Power
ECM
EFI MAIN
MREL+B
15 ASource IC
Soak Timer ICMain Relay
Control IC
Battery DI±442
± DIAGNOSTICSENGINE
636 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P2610 ECM/PCM Internal Engine OFF Timer Perfor-
mance
DTC SUMMARY
DTCMonitoring ItemsMalfunction Detection ConditionsTrouble AreasDetection
TimingsDetection
Logic
P2610Soak timer (built into ECM)ECM internal malfunctionECMEngine
running2 trip
CIRCUIT DESCRIPTION
To ensure the accuracy of the EVAP (Evaporative Emission) monitor values, the soak timer, which is built
into the ECM, measures 5 hours (
15 minutes) from when the ignition switch is turned OFF, before the moni-
tor is run. This allows the fuel to cool down, which stabilizes the Fuel Tank Pressure (FTP). When 5 hours
have elapsed, the ECM turns on.
MONITOR DESCRIPTION
5 hours after the ignition switch is turned OFF, the soak timer activates the ECM to begin the EVAP system
monitor. While the engine is running, the ECM monitors the synchronization of the soak timer and the CPU
clock. If these two are not synchronized, the ECM interprets this as a malfunction, illuminates the MIL and
sets the DTC (2 trip detection logic).
MONITOR STRATEGY
Related DTCsP2610Soak timer (built into ECM)
Required sensors/componentsECM
Frequency of operationOnce per driving cycle
Duration10 min.
MIL operation2 driving cycles
Sequence of operationNone
DIDFX±01

A23659
Wire Harness Side:
HT
A38
Sensor 1A/F Sensor Connector
AF+
Front ViewAF±
+B A39
B17415A55007
E7ECM Connector
HA1A
A1A+
A1A±
A2A+
A2A±HA2A
A23512
Reference (Bank 1 Sensor 1 System Drawing):
A/F Sensor A/F Relay
Heater
Sensor
A1A+ HA1A
Duty
Control ECM
From
Battery
A/F Heater
Fuse
A1A±
To EFI Relay
± DIAGNOSTICSENGINE
DI±457
651 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check for open and short in harness and connector between ECM and A/F sen-
sor.
PREPARATION:
(a) Disconnect the A38 or A39 A/F sensor connector.
(b) Turn the ignition switch to ON.
CHECK:
(a) Measure the voltage between the +B terminal of the A/F
sensor connector and body ground.
OK:
Standard:
Tester ConnectionsSpecified Conditions
+B (2) ± Body groundBetween 9 V and 14 V
PREPARATION:
(a) Turn the ignition switch to OFF.
(b) Disconnect the E7 ECM connector.
CHECK:
(a) Check the resistance.
OK:
Standard (Check for open):
Tester ConnectionsSpecified Conditions
HT (A38±1) ± HA1A (E7±2)
HT (A39±1) ± HA2A (E7±1)Below 1 W
AF+ (A38±3) ± A1A+ (E7±22)
AF+ (A39±3) ± A2A+ (E7±23)Below 1 W
AF± (A38±4) ± A1A± (E7±30)
AF± (A39±4) ± A2A± (E7±31)Below 1 W
Standard (Check for short):
Tester ConnectionsSpecified Conditions
HT (A38±1) or HA1A (E7±2) ± Body ground
HT (A39±1) or HA2A (E7±1) ± Body ground10 kW or higher
AF+ (A38±3) or A1A+ (E7±22) ± Body ground
AF+ (A39±3) or A2A+ (E7±23) ± Body ground10 kW or higher
AF± (A38±4) or A1A± (E7±30) ± Body ground
AF± (A39±4) or A2A± (E7±31) ± Body ground10 kW or higher