Page 644 of 4323

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
Page 645 of 4323

± DIAGNOSTICSENGINE
DI±443
637 Author: Date:
2005 SEQUOIA (RM1146U)
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
Battery voltage8 V±
Ignition switchON
StarterOFF
EngineRunning
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Soak time measurement when ECM CPU clock counts 10
min.Less than 7 min., or more than 13 min.
INSPECTION PROCEDURE
HINT:
DTC P2610 is set if an internal ECM problem is detected. Diagnostic procedures are not required. ECM
replacement is required.
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.
1 Replace ECM (See page SF±80).
NEXT
Check whether DTC output recurs.
(a) Connect a hand±held tester to the DLC3.
(b) Turn the ignition switch to ON.
(c) Clear DTCs (see page DI±43).
(d) Start the engine and wait for 10 minutes or more.
(e) On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / PEND-
ING CODES.
(f) If no pending DTC is displayed, the repair has been successfully completed.
Page 646 of 4323
DI±444
± DIAGNOSTICSENGINE
638 Author: Date:
2005 SEQUOIA (RM1146U)
DTC U0001 High Speed Can Communication Circuit
CIRCUIT DESCRIPTION
The engine control unit and the transmission control unit are located inside the ECM. The engine control unit
intercommunicates with the transmission control ECU with the Controller Area Network (CAN).
If there is a problem in this intercommunication, the ECM sets a DTC.
DTC No.DTC Detection ConditionTrouble Area
U0001
The following conditions are met for 2 seconds (1 trip detection
logic):
(a) Ignition switch ON
(b) Battery voltage is 10 V or more
(c) No intercommunication between engine control ECU and
transmission control ECU
ECM
INSPECTION PROCEDURE
Replace ECM (See page SF±80)
DID8J±01
Page 651 of 4323

± DIAGNOSTICSENGINE
DI±449
643 Author: Date:
2005 SEQUOIA (RM1146U)
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
Following values are values when atmo-
spheric is 760 mmHg (100 kPa)±
EVAP key±off monitor runs when all of the
following conditions met:±
Atmospheric pressure525 to 825 mmHg (70 to 110 kPa)
Battery voltage10.5 V±
Vehicle speed±4 km/h (2.5 mph)
Ignition switchOFF
Engine conditionNot running
Time after engine stopped5 hours
FTP sensor malfunction (P0450, P0452,
P0453)Not detected
Purge VSVNot operated by scan tool
Vent valveNot operated by scan tool
Leak detection pumpNot operated by scan tool
Both of the following conditions are met
before IG switch OFFCondition 1 and 2
1. Duration that vehicle is driven5 min.±
2. Purge flowExecuted
ECT4.4 to 35°C (40 to 95°F)
IAT4.4 to 35°C (40 to 95°F)
Example of re±start time±
First time7 hours
Second time9 hours and 30 min.
Key±off monitor sequence1 to 8
1. Atmospheric pressure±
Next sequence is run if following condition
set±
Atmospheric pressure change for 10 sec.±2.25 mmHg (0.3 kPa) for 1 sec.
2. First reference pressure±
Next sequence is run if all of following
conditions setCondition 1, 2 and 3
1. FTP when 4 sec. after reference pres-
sure measurement±±7.5 mmHg (±1 kPa)
2. Reference pressure±36.38 to ±7.93 mmHg (±4.85 to ±1.057 kPa)
3. Reference pressureSaturated
3. Vent valve stuck closed check±
Next sequence is run if following condition
set±
FTP change for 10 sec. after vent valve
ON (closed)2.25 mmHg (0.3 kPa)±
4. Vacuum introduction and leak±
Page 655 of 4323

± DIAGNOSTICSENGINE
DI±453
647 Author: Date:
2005 SEQUOIA (RM1146U)
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
Battery voltage11 V±
ECT75°C (167°F)±
IdleOFF
Engine RPM±4,000 rpm
A/F sensor statusActivated
Fuel cutOFF
Engine load10 to 70%
Estimated catalyst temperature500 to 800°C (932 to 1,472°F)
Shift position2nd±
Catalyst monitorNot executing
Intake air amount2.5 to 12 g/sec
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Response rate deterioration levelLess than 0.2 V
Number of average5 or more
MONITOR RESULT
Refer to page DI±26 for detailed information.
The test value and test limit information are described as shown in the following table. Check the monitor
result and test values after performing the monitor drive pattern (refer to ºConfirmation Monitorº).
MID (Monitor Identification Data) is assigned to each emissions±related component.
TID (Test Identification Data) is assigned to each test value.
Scaling is used to calculate the test value indicated on generic OBD ll scan tools.
A/F sensor bank 1 sensor 1
MIDTIDScalingDescription of Test ValueMinimum Test LimitMaximum Test Limit
$01$8EMultiply by 0.0003
(no dimension)Response rate deterioration level for
A/F sensorMalfunction criterionFF
A/F sensor bank 2 sensor 1
MIDTIDScalingDescription of Test ValueMinimum Test LimitMaximum Test Limit
$05$8EMultiply by 0.0003
(no dimension)Response rate deterioration level for
A/F sensorMalfunction criterionFF
WIRING DIAGRAM
Refer to DTC P2195 on page DI±383.
Page 659 of 4323

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
Page 666 of 4323
A23494
Pump Module (fig. 1):
Condition: Purge FlowCondition: Leak Check
From Refueling Valve
To Air Filter
(Atmosphere)
Vacuum Pump: OFFVent Valve: OFF
(vent)
Pressure Sensor 0.02 Inch Orifice
Canister
: Airflow
Vacuum Pump: ON
Vent Valve: ON
(closed)
A23495
Pressure Sensor Specification (fig. 2)
Output Voltage
Usable Range
4.900 V
4.150 V
1.425 V
0.450 V
Malfunction Area
Pressure
60
kPa11 0
kPa
Malfunction Area
Standard atmospheric pressure is 101.3 kPaHINT:
A23496
Soak Timer Circuit (fig. 3)
Ignition Switch
IGSW
Power
ECM
EFI MAIN
MREL+B
15 ASource IC
Soak Timer IC Main Relay
Control IC
Battery DI±464
± DIAGNOSTICSENGINE
658 Author: Date:
2005 SEQUOIA (RM1146U)
Page 667 of 4323
A23565
L5
Pump Module
Pressure Sensor
Vacuum Pump
Vent Valve
Engine Room R/B
BatteryJ/C
V4
Purge
VSVVC
PPMP
E2
MPMP
VPMP
PRG
MREL
EFI Relay
F10
FL Block
54
BBEFI No.1
2D1
53EFI No.2
2A 2 4
1
8
9 3
2
G±R AA J/C J2
G±RG±R
G±R G±R
IA44J/C J16
BBBJ/C
IG422
G±RW±G
E8 34
B±W
E68
B±WIA4
14
2H6
21 2F1
W±B
J/C J5 AJ48
J49 FLG±R BB12
G±R
G±R
BN15 P±L
BN1BN1 BN1 BN1 BN1
P±L 6
BB18
P±L P±L
J49
J48 B
H
E456
V±G
J48K
J49E
V±G
BB17
V±G V±G4 G±W3
G±W
BB24
G±W
IJ33
G±W
IG46
G±W
E8 2822
E4 E4 R±G
IJ34
R±G
BB22
R±G 2
R±GG±B1
G±B
BB23
G±B
IJ314
G±B
IG47
G±B
E823
BN1 8 W±B
W±B
BI
EDECM
± DIAGNOSTICSENGINE
DI±465
659 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM