TOYOTA SIENNA 2007 Service Repair Manual

2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEMES–115
ES
OK
(a) Disconnect the A5 or A6 A/F sensor connector.
(b) Disconnect the E10 ECM connector.
(c) Measure the resistance according to the value(s) in the
table below.
Standard resistance:
Check for open
Check for short
(d) Reconnect the ECM connector.
(e) Reconnect the A/F sensor connectors.
NG
OK
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Turn the intelligent tester ON.
(d) Clear the DTCs (See page ES-39).
(e) Start the engine.
(f) Allow the engine to idle for 1 minute or more.
(g) Select the following menu items: DIAGNOSIS /
ENHANCED OBD II / DTC INFO / CURRENT CODES.
(h) Read the DTCs.
Result
B REPAIR OR REPLACE HARNESS OR CONNECTOR (A/F RELAY - BATTERY)
7CHECK HARNESS AND CONNECTOR (A/F RELAY - ECM)
A085836E04
Tester Connection Specified Condition
HT (A5-1) - HA1A (E10-2) Below 1
HT (A6-1) - HA2A (E10-1) Below 1
Tester Connection Specified Condition
HT (A5-1) or HA1A (E10-2) - Body ground 10 k
or higher
HT (A6-1) or HA2A (E10-1) - Body ground 10 k
or higher
REPAIR OR REPLACE HARNESS OR
CONNECTOR (A/F RELAY - ECM)
8CHECK WHETHER DTC OUTPUT RECURS
Display (DTC Output) Proceed to
No output A
P0031, P0032, P0051 and/or P0052 B
REPLACE ECM (See page ES-498)

ES–1162GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
ES
A
CHECK FOR INTERMITTENT PROBLEMS

2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEMES–117
ES
HINT:
Sensor 2 refers to the sensor mounted behind the Three-Way Catalytic Converter (TWC) and located
furthest from the engine assembly.
DESCRIPTION
Refer to DTC P0136 (See page ES-160).
HINT:
When any of these DTCs are set, the ECM enters fail-safe mode. The ECM turns off the Heated Oxygen
(HO2) sensor heater in fail-safe mode. Fail-safe mode continues until the ignition switch is turned off.
DTC P0037Oxygen Sensor Heater Control Circuit Low
(Bank 1 Sensor 2)
DTC P0038Oxygen Sensor Heater Control Circuit High
(Bank 1 Sensor 2)
DTC P0057Oxygen Sensor Heater Control Circuit Low
(Bank 2 Sensor 2)
DTC P0058Oxygen Sensor Heater Control Circuit High
(Bank 2 Sensor 2)
DTC P0141Oxygen Sensor Heater Circuit Malfunction
(Bank 1 Sensor 2)
DTC P0161Oxygen Sensor Heater Circuit Malfunction
(Bank 2 Sensor 2)
A103832E63

ES–1182GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
ES
HINT:
• Bank 1 refers to the bank that includes cylinder No. 1.
• Bank 2 refers to the bank that does not include cylinder No. 1.
• Sensor 1 refers to the sensor closest to the engine assembly.
• Sensor 2 refers to the sensor furthest away from the engine assembly.
MONITOR DESCRIPTION
The sensing position of the Heated Oxygen (HO2) sensor has a zirconia element which is used to detect
the oxygen concentration in the exhaust gas. If the zirconia element is at the appropriate temperature,
and the difference between the oxygen concentrations surrounding the inside and outside surfaces of the
sensor is large, the zirconia element generates voltage signals. In order to increase the oxygen
concentration detecting capacity of the zirconia element, the ECM supplements the heat from the exhaust
with heat from a heating element inside the sensor.
Heated oxygen sensor heater range check (P0037, P0038, P0057 and P0058):
The ECM monitors the current applied to the O2 sensor heater to check the heater for malfunctions. If the
current is below the threshold value, the ECM will determine that there is an open circuit in the heater. If
the current is above the threshold value, the ECM will determine that there is a short circuit in the heater.
Example:
The ECM sets DTC P0038 or P0058 when the current in the HO2 sensor heater is more than 2 A.
Conversely, when the heater current is less than 0.3 A, DTC P0037 or P0057 is set.
Heated oxygen sensor heater performance (P0141 and P0161):
After the accumulated heater ON time exceeds 100 seconds, the ECM calculates the heater resistance
using the battery voltage and the current applied to the heater. If the resistance is above the threshold
value, the ECM will determine that there is a malfunction in the HO2S heater and set DTC P0141 and
P0161.
MONITOR STRATEGY
DTC No. DTC Detection Condition Trouble Area
P0037
P0057Heated Oxygen (HO2) sensor heater current is less
than 0.3 A (1 trip detection logic)• Open in HO2 sensor heater circuit
• HO2 sensor heater
• EFI relay
•ECM
P0038
P0058Heated Oxygen (HO2) sensor heater current is more
than 2 A (1 trip detection logic)• Open in HO2 sensor heater circuit
• HO2 sensor heater
• EFI relay
•ECM
P0141
P0161Cumulative heater resistance correction value exceeds
the acceptable threshold (2 trip detection logic)• HO2 sensor
•ECM
Related DTCsP0037: Heated oxygen sensor heater (bank 1) open/short (Low electrical current)
P0038: Heated oxygen sensor heater (bank 1) open/short (High electrical current)
P0057: Heated oxygen sensor heater (bank 2) open/short (Low electrical current)
P0058: Heated oxygen sensor heater (bank 2) open/short (High electrical current)
P0141: Heated oxygen sensor heater performance (bank 1 sensor 2)
P0161: Heated oxygen sensor heater performance (bank 2 sensor 2)
Required Sensors / Components (Main) Heated oxygen sensor heater (bank 1 and 2)
Required Sensors / Components (Related) Vehicle speed sensor
Frequency of Operation Continuous
Duration0.5 seconds: P0037 and P0057
1 second: P0038 and P0058
10 seconds: P0141 and P0161
MIL OperationImmediate: P0037, P0038, P0057 and P0058
2 driving cycles: P0141 and P0161
Sequence of Operation None

2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEMES–119
ES
TYPICAL ENABLING CONDITIONS
All:
P0037 and P0057:
P0038 and P0058 Case 1:
P0038 and P0058 Case 2:
P0141 and P0161:
TYPICAL MALFUNCTION THRESHOLDS
P0037 and P0057:
P0038 and P0058:
P0141 and P0161 (Heater performance monitor check):
COMPONENT OPERATING RANGE
MONITOR RESULT
Refer to CHECKING MONITOR STATUS (See page ES-19).
WIRING DIAGRAM
Refer to DTC P0136 (See page ES-167).
INSPECTION PROCEDURE
HINT:
• If other DTCs relating to different systems that have terminal E2 as the ground terminal are output
simultaneously, terminal E2 may have an open circuit.
Monitor runs whenever following DTCs are not present None
Battery voltage 10.5 to 20 V
Battery voltage 10.5 V or more
Engine Running
Sta r t e r OF F
Battery voltage 10.5 to 20 V
One of the following conditions is met: Condition A or B
A. All of the following conditions are met: Conditions 1, 2, 3, 4 and 5
1. Battery voltage 10.5 V or more
2. Fuel cut OFF
3. Time after fuel cut ON to OFF 30 seconds or more
4. Accumulated heater ON time 100 seconds or more
5. Learned heater OFF current operation Completed
B. Duration that rear heated oxygen sensor impedance is less than 15
k
2 seconds or more
Heater Current - Learned heater OFF current Less than 0.3 A
Learned heater OFF current More than 2 A
Heater Current - Learned heater OFF current 2 A or more
Accumulated heater resistance Varies with sensor element temperature (Example: More than 23
)
Heated Oxygen (HO2) sensor heater current0.4 to 1 A (when engine idles, HO2 sensor warmed up and battery voltage 11 to 14
V)

ES–1202GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
ES
• Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition
information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame
data can be helpful in determining whether the vehicle was running or stopped, whether the engine
was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the
time of a malfunction.
(a) Disconnect the H14 heated oxygen (HO2) sensor
connector (Bank 1 Sensor 2) or H9 heated oxygen
sensor connector (Bank 2 Sensor 2).
(b) Measure the resistance according to the value(s) in the
table below.
Standard resistance:
Bank 1
Bank 2
(c) Reconnect the HO2 sensor connectors.
NG
OK
1INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)
A112643E03
Tester Connection Condition Specified Condition
HT (1) - +B (2) 20
C (68F) 11 to 16
HT (1) - E1 (4) Always 10 k or higher
Tester Connection Condition Specified Condition
HT (1) - +B (2) 20
C (68F) 11 to 16
HT (1) - E1 (4) Always 10 k or higher
REPLACE HEATED OXYGEN SENSOR

2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEMES–121
ES
(a) Disconnect the H14 or H9 HO2 sensor connector.
(b) Turn the ignition switch to the ON position.
(c) Measure the voltage according to the value(s) in the
table below.
Standard voltage
(d) Reconnect the HO2 sensor connector.
OK
NG
(a) Remove the EFI No. 2 fuse from the engine room
junction block.
(b) Measure the resistance according to the value(s) in the
table below.
Standard resistance:
Below 1
(c) Reinstall the EFI No. 2 fuse.
NG
OK
2CHECK TERMINAL VOLTAGE (+B OF SENSOR)
A163150E01
Tester Connection Specified Condition
+B (H14-2) - Body ground 9 to 14 V
+B (H9-2) - Body ground 9 to 14 V
Go to step 5
3INSPECT FUSE (EFI NO. 2 FUSE)
A162360E08
REPLACE EFI NO. 2 FUSE

ES–1222GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
ES
(a) Remove the EFI relay from the engine room junction
block.
(b) Measure the resistance according to the value(s) in the
table below.
Standard resistance
(c) Reinstall the EFI relay.
NG
OK
(a) Disconnect the H14 or H9 HO2 sensor connector.
(b) Disconnect the E9 and E10 ECM connectors.
(c) Measure the resistance according to the value(s) in the
table below.
Standard resistance:
Check for open
Check for short
(d) Reconnect the ECM connectors.
(e) Reconnect the HO2 sensor connectors.
NG
4INSPECT RELAY (EFI RELAY)
B016200
Tester Connection Specified Condition
3 - 5 10 k
or higher
3 - 5Below 1
(Apply battery voltage between terminals 1 and 2)
REPLACE RELAY (EFI RELAY)
REPAIR OR REPLACE HARNESS OR CONNECTOR (HO2 SENSOR - EFI RELAY)
5CHECK HARNESS AND CONNECTOR (HO2 SENSOR - ECM)
A163309E01
Tester Connection Specified Condition
HT (H14-1) - HT1B (E9-1) Below 1
OX (H14-3) - OX1B (E9-18) Below 1
HT (H9-1) - HT2B (E10-5) Below 1
OX (H9-3) - OX2B (E10-33) Below 1
Tester Connection Specified Condition
HT (H14-1) or HT1B (E9-1) - Body ground 10 k
or higher
OX (H14-3) or OX1B (E9-18) - Body ground 10 k
or higher
HT (H9-1) or HT2B (E10-5) - Body ground 10 k
or higher
OX (H9-3) or OX2B (E10-33) - Body ground 10 k
or higher
REPAIR OR REPLACE HARNESS OR
CONNECTOR (HO2 SENSOR - ECM)

2GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEMES–123
ES
OK
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) Turn the intelligent tester ON.
(d) Clear the DTCs (See page ES-39).
(e) Start the engine.
(f) Allow the engine to idle for 1 minute or more.
(g) Select the following menu items: DIAGNOSIS /
ENHANCED OBD II / DTC INFO / CURRENT CODES.
(h) Read the DTCs.
Result
B
A
6CHECK WHETHER DTC OUTPUT RECURS
Display (DTC Output) Proceed to
No output A
P0037, P0038, P0057, P0058, P0141 and/or P0161 B
REPLACE ECM
CHECK FOR INTERMITTENT PROBLEMS

ES–1242GR-FE ENGINE CONTROL SYSTEM – SFI SYSTEM
ES
DESCRIPTION
The Mass Air Flow (MAF) meter is a sensor that measures the amount of air flowing through the throttle
valve. The ECM uses this information to determine the fuel injection time and to provide appropriate air-
fuel ratio. Inside the MAF meter, there is a heated platinum wire which is exposed to the flow of intake air.
By applying a specific electrical current to the wire, the ECM heats it to a specific temperature. The flow of
incoming air cools both the wire and an internal thermistor, changing their resistance. To maintain a
constant current value, the ECM varies the voltage applied to these components in the MAF meter. The
voltage level is proportional to the air flow through the sensor, and the ECM uses it to calculate the intake
air volume.
The circuit is constructed so that the platinum hot wire and the temperature sensor provide a bridge
circuit, and the power transistor is controlled so that the potentials of A and B remain equal to maintain the
predetermined temperature.
HINT:
When any of these DTCs are set, the ECM enters fail-safe mode. During fail-safe mode, the ignition
timing is calculated by the ECM, according to the engine RPM and throttle valve position. Fail-safe mode
continues until a pass condition is detected.
HINT:
When any of these DTCs are set, check the air-flow rate by selecting the following menu items on an
intelligent tester: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / MAF.
DTC P0100 Mass or Volume Air Flow Circuit
DTC P0102 Mass or Volume Air Flow Circuit Low Input
DTC P0103 Mass or Volume Air Flow Circuit High Input
DTC No. DTC Detection Condition Trouble Area
P0100Open or short in Mass Air Flow (MAF) meter circuit for 3
seconds• Open or short in MAF meter circuit
• MAF meter
•ECM
P0102Open in Mass Air Flow (MAF) meter circuit for 3
seconds• Open in MAF meter circuit
• Short in ground circuit
• MAF meter
•ECM
P0103Short in Mass Air Flow (MAF) meter circuit for 3
seconds• Short in MAF meter circuit (+B circuit)
• MAF meter
•ECM
A140749E02