EC-32
[VQ35DE]
ENGINE CONTROL SYSTEM
Revision: 2006 December 2006 FX35/FX45
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system provides the best air-fuel mixture ratio for driveability and emission control.
The three way catalyst 1 can then better reduce CO, HC and NOx emissions. This system uses air fuel ratio
(A/F) sensor 1 in the exhaust manifold to monitor whether the engine operation is rich or lean. The ECM
adjusts the injection pulse width according to the sensor voltage signal. For more information about air fuel
ratio (A/F) sensor 1, refer to EC-240, "
DTC P0131, P0151 A/F SENSOR 1" . This maintains the mixture ratio
within the range of stoichiometric (ideal air-fuel mixture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 is located downstream of the three way catalyst 1. Even if the switching characteris-
tics of air fuel ratio (A/F) sensor 1 shift, the air-fuel ratio is controlled to stoichiometric by the signal from
heated oxygen sensor 2.
Open Loop Control
The open loop system condition refers to when the ECM detects any of the following conditions. Feedback
control stops in order to maintain stabilized fuel combustion.
Deceleration and acceleration
High-load, high-speed operation
Malfunction of air fuel ratio (A/F) sensor 1 or its circuit
Insufficient activation of air fuel ratio (A/F) sensor 1 at low engine coolant temperature
High engine coolant temperature
During warm-up
After shifting from N to D
When starting the engine
MIXTURE RATIO SELF-LEARNING CONTROL
The mixture ratio feedback control system monitors the mixture ratio signal transmitted from air fuel ratio (A/F)
sensor 1. This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio as close to
the theoretical mixture ratio as possible. However, the basic mixture ratio is not necessarily controlled as orig-
inally designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic
changes during operation (i.e., fuel injector clogging) directly affect mixture ratio.
Accordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This is
then computed in terms of “injection pulse duration” to automatically compensate for the difference between
the two ratios.
“Fuel trim” refers to the feedback compensation value compared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
“Short term fuel trim” is the short-term fuel compensation used to maintain the mixture ratio at its theoretical
value. The signal from air fuel ratio (A/F) sensor 1 indicates whether the mixture ratio is RICH or LEAN com-
pared to the theoretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is rich, and
an increase in fuel volume if it is lean.
“Long term fuel trim” is overall fuel compensation carried out long-term to compensate for continual deviation
of the short term fuel trim from the central value. Such deviation will occur due to individual engine differences,
wear over time and changes in the usage environment.
PBIB3020E
EC-60
[VQ35DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
Revision: 2006 December 2006 FX35/FX45
For example, the EGR malfunction (Priority: 2) was detected and the freeze frame data was stored in the 2nd
trip. After that when the misfire (Priority: 1) is detected in another trip, the freeze frame data will be updated
from the EGR malfunction to the misfire. The 1st trip freeze frame data is updated each time a different mal-
function is detected. There is no priority for 1st trip freeze frame data. However, once freeze frame data is
stored in the ECM memory, 1st trip freeze data is no longer stored (because only one freeze frame data or 1st
trip freeze frame data can be stored in the ECM). If freeze frame data is stored in the ECM memory and freeze
frame data with the same priority occurs later, the first (original) freeze frame data remains unchanged in the
ECM memory.
Both 1st trip freeze frame data and freeze frame data (along with the DTCs) are cleared when the ECM mem-
ory is erased. Procedures for clearing the ECM memory are described in EC-67, "
HOW TO ERASE EMIS-
SION-RELATED DIAGNOSTIC INFORMATION" .
SYSTEM READINESS TEST (SRT) CODE
System Readiness Test (SRT) code is specified in Service $01 of SAE J1979.
As part of an enhanced emissions test for Inspection & Maintenance (I/M), certain states require the status of
SRT be used to indicate whether the ECM has completed self-diagnosis of major emission systems and com-
ponents. Completion must be verified in order for the emissions inspection to proceed.
If a vehicle is rejected for a State emissions inspection due to one or more SRT items indicating “INCMP”, use
the information in this Service Manual to set the SRT to “CMPLT”.
In most cases the ECM will automatically complete its self-diagnosis cycle during normal usage, and the SRT
status will indicate “CMPLT” for each application system. Once set as “CMPLT”, the SRT status remains
“CMPLT” until the self-diagnosis memory is erased.
Occasionally, certain portions of the self-diagnostic test may not be completed as a result of the customer's
normal driving pattern; the SRT will indicate “INCMP” for these items.
NOTE:
The SRT will also indicate “INCMP” if the self-diagnosis memory is erased for any reason or if the ECM mem-
ory power supply is interrupted for several hours.
If, during the state emissions inspection, the SRT indicates “CMPLT” for all test items, the inspector will con-
tinue with the emissions test. However, if the SRT indicates “INCMP” for one or more of the SRT items the
vehicle is returned to the customer untested.
NOTE:
If MIL is ON during the state emissions inspection, the vehicle is also returned to the customer untested even
though the SRT indicates “CMPLT” for all test items. Therefore, it is important to check SRT (“CMPLT”) and
DTC (No DTCs) before the inspection.
SRT Item
The table below shows required self-diagnostic items to set the SRT to “CMPLT”.
*: If completion of several SRTs is required, perform driving patterns (DTC confirmation procedure), one by one based on the pr iority for
models with CONSULT-II.
SRT Set Timing
SRT is set as “CMPLT” after self-diagnosis has been performed one or more times. Completion of SRT is
done regardless of whether the result is OK or NG. The set timing is different between OK and NG results and
is shown in the table below.
SRT item
(CONSULT-II indica-
tion) Perfor-
mance Pri-
ority* Required self-diagnostic items to set the SRT to “CMPLT”
Corresponding DTC
No.
CATALYST 2 Three way catalyst function P0420, P0430
EVAP SYSTEM 1 EVAP control system P0442
2 EVAP control system P0456
2 EVAP control system purge flow monitoring P0441
HO2S 2 Air fuel ratio (A/F) sensor 1 P0133, P0153
Heated oxygen sensor 2 P0137, P0157
Heated oxygen sensor 2 P0138, P0158
Heated oxygen sensor 2 P0139, P0159
EC-66
[VQ35DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
Revision: 2006 December 2006 FX35/FX45
Item Self-diagnostic test item DTC Test value
(GST display) Test limit Conversion
TID CID
CATALYST Three way catalyst function (Bank 1)
P0420 01H 01H Max. 1/128
P0420 02H 81H Min. 1
Three way catalyst function (Bank 2) P0430 03H 02H Max. 1/128
P0430 04H 82H Min. 1
EVAP SYSTEM EVAP control system (Small leak) P0442 05H 03H Max.
1/128mm
2
EVAP control system purge flow monitoring P0441 06H 83H Min. 20mV
EVAP control system (Very small leak) P0456 07H 03H Max. 1/128mm
2
HO2S Air fuel ratio (A/F) sensor 1 (Bank 1)
P0131 41H 8EH Min. 5 mV
P0132 42H 0EH Max. 5 mV
P2A00 43H 0EH Max. 0.002
P2A00 44H 8EH Min. 0.002 P0133 45H 8EH Min. 0.004
P0130 46H 0EH Max. 5 mV
P0130 47H 8EH Min. 5 mV
P0133 48H 8EH Min. 0.004
Air fuel ratio (A/F) sensor 1 (Bank 2) P0151 4CH 8FH Min. 5 mV
P0152 4DH 0FH Max. 5 mV
P2A03 4EH 0FH Max. 0.002
P2A03 4FH 8FH Min. 0.002 P0153 50H 8FH Min. 0.004
P0150 51H 0FH Max. 5 mV
P0150 52H 8FH Min. 5 mV
P0153 53H 8FH Min. 0.004
Heated oxygen sensor 2 (Bank 1) P0139 19H 86H Min. 10mV/500ms
P0137 1AH 86H Min. 10mV
P0138 1BH 06H Max. 10mV
P0138 1CH 06H Max. 10mV
Heated oxygen sensor 2 (Bank 2) P0159 21H 87H Min. 10mV/500ms
P0157 22H 87H Min. 10mV
P0158 23H 07H Max. 10mV
P0158 24H 07H Max. 10mV
HO2S HEATER Air fuel ratio (A/F) sensor 1 heater (Bank 1)
P0032 57H 10H Max. 5 mV
P0031 58H 90H Min. 5 mV
Air fuel ratio (A/F) sensor 1 heater (Bank 2) P0052 59H 11H Max. 5 mV
P0051 5AH 91H Min. 5 mV
Heated oxygen sensor 2 heater (Bank 1) P0038 2DH 0AH Max. 20mV
P0037 2EH 8AH Min. 20mV
Heated oxygen sensor 2 heater (Bank 2) P0058 2FH 0BH Max. 20mV
P0057 30H 8BH Min. 20mV
TROUBLE DIAGNOSIS EC-95
[VQ35DE]
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EC
Revision: 2006 December 2006 FX35/FX45
*: Models with ICC. 2
P0031 P0032 P0051 P0052 Air fuel ratio (A/F) sensor 1 heater
P0037 P0038 P0057 P0058 Heated oxygen sensor 2 heater
P0075 P0081 Intake valve timing control solenoid valve
P0130 P0131 P0132 P0133 P0150 P0151 P0152 P0153 P2A00 P2A03 Air fuel ratio (A/F) sensor 1
P0137 P0138 P0139 P0157 P0158 P0159 Heated oxygen sensor 2
P0441 EVAP control system purge flow monitoring
P0443 P0444 P0445 EVAP canister purge volume control solenoid valve
P0447 P0448 EVAP canister vent control valve
P0451 P0452 P0453 EVAP control system pressure sensor
P0550 Power steering pressure sensor
P0603 ECM power supply
P0710 P0717 P0720 P0740 P0744 P0745 P1730 P1752 P1754 P1757 P1759 P1762 P1764 P1767 P1769 P1772
P1774 A/T related sensors, solenoid valves and switches
P1217 Engine over temperature (OVERHEAT)
P1805 Brake switch
P2100 P2103 P2118 Electric throttle control actuator
P2101 Electric throttle control function
3
P0011 P0021 Intake valve timing control
P0171 P0172 P0174 P0175 Fuel injection system function
P0300 - P0306 Misfire
P0420 P0430 Three way catalyst function
P0442 EVAP control system (SMALL LEAK)
P0455 EVAP control system (GROSS LEAK)
P0456 EVAP control system (VERY SMALL LEAK)
P0506 P0507 Idle speed control system
P1148 P1168 Closed loop control
P1211 TCS control unit
P1212 TCS communication line
P1564 ICC steering switch/ASCD steering switch
P1568 ICC command valve*
P1572 ICC brake switch/ASCD brake switch
P1574 ICC vehicle speed sensor/ASCD vehicle speed sensor
P1715 Turbine revolution sensor
P2119 Electric throttle control actuator
Priority Detected items (DTC)
TROUBLE DIAGNOSIS EC-111
[VQ35DE]
C
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EC
Revision: 2006 December 2006 FX35/FX453R Throttle control motor relay
power supply [Ignition switch: ON] BATTERY VOLTAGE
(11 - 14V)
4L/W Throttle control motor
(Close) [Ignition switch: ON]
Engine stopped
Selector lever: D
Accelerator pedal: Fully released 0 - 14V
5L/B Throttle control motor
(Open) [Ignition switch: ON]
Engine stopped
Selector lever: D
Accelerator pedal: Fully depressed 0 - 14V
6R Heated oxygen sensor 2
heater (bank 2) [Engine is running]
Engine speed: Below 3,600 rpm after the
following conditions are met
–Engine: After warming up
–Keeping the engine speed between 3,500
and 4,000 rpm for 1 minute and at idle for 1
minute under no load 0 - 1.0V
[Ignition switch: ON]
Engine stopped
[Engine is running]
Engine speed: Above 3,600 rpm BATTERY VOLTAGE
(11 - 14V)
10 OR Intake valve timing control
solenoid valve (bank 2) [Engine is running]
Warm-up condition
Idle speed
BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
Warm-up condition
When revving engine up to 2,500 rpm
quickly 7 - 12V
11 B R Intake valve timing control
solenoid valve (bank 1) [Engine is running]
Warm-up condition
Idle speed
BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
Warm-up condition
When revving engine up to 2,500 rpm
quickly 7 - 12V
TER-
MINAL NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
PBIB1104E
PBIB1105E
PBIB1790E
PBIB1790E
TROUBLE DIAGNOSIS EC-113
[VQ35DE]
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EC
Revision: 2006 December 2006 FX35/FX45
21
22
23 W
G
R Fuel injector No. 5
Fuel injector No. 3
Fuel injector No. 1 [Engine is running]
Warm-up condition
Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idle BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
Warm-up condition
Engine speed: 2,000 rpm BATTERY VOLTAGE
(11 - 14V)
24 L A/F sensor 1 heater
(Bank 2) [Engine is running]
Warm-up condition
Idle speed Approximately 5V
25 P Heated oxygen sensor 2
heater (bank 1) [Engine is running]
Engine speed: Below 3,600 rpm after the
following conditions are met
–Engine: After warming up
–Keeping the engine speed between 3,500
and 4,000 rpm for 1 minute and at idle for 1
minute under no load 0 - 1.0V
[Ignition switch: ON]
Engine stopped
[Engine is running]
Engine speed: Above 3,600 rpm BATTERY VOLTAGE
(11 - 14V)
32 OR EVAP control system pres-
sure sensor [Ignition switch: ON]
Approximately 1.8 - 4.8V
TER-
MINAL NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
SEC984C
SEC985C
PBIB1584E
TROUBLE DIAGNOSIS EC-115
[VQ35DE]
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Revision: 2006 December 2006 FX35/FX4547 L Sensor power supply
(Throttle position sensor) [Ignition switch: ON]
Approximately 5V
48 LG Sensor power supply
(EVAP control system pres-
sure sensor) [Ignition switch: ON]
Approximately 5V
49 PU Sensor power supply
(Refrigerant pressure sen-
sor) [Ignition switch: ON]
Approximately 5V
50 W Throttle position sensor 1 [Ignition switch: ON]
Engine stopped
Selector lever: D
Accelerator pedal: Fully released
More than 0.36V
[Ignition switch: ON]
Engine stopped
Selector lever: D
Accelerator pedal: Fully depressed Less than 4.75V
51 L/W Mass air flow sensor [Engine is running]
Warm-up condition
Idle speed
1.0 - 1.2V
[Engine is running]
Warm-up condition
Engine speed: 2,500 rpm 1.6 - 2.0V
55 W/R Heated oxygen sensor 2
(bank 2) [Engine is running]
Revving engine from idle to 3,000 rpm
quickly after the following conditions are met
–Engine: After warming up
–After keeping the engine speed between
3,500 and 4,000 rpm for 1 minute and at idle
for 1 minute under no load 0 - Approximately 1.0V
57 G A/F sensor 1 (Bank 2) [Engine is running]
Warm-up condition
Idle speed Approximately 2.6V
58 Y Approximately 2.3V
76 P Approximately 3.1V
77 BR Approximately 2.3V
60
61
62 PU
L
Y Ignition signal No. 5
Ignition signal No. 3
Ignition signal No. 1 [Engine is running]
Warm-up condition
Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idle 0 - 0.2V
[Engine is running]
Warm-up condition
Engine speed: 2,500 rpm 0.1 - 0.4V
TER-
MINAL NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
SEC986C
SEC987C
EC-116
[VQ35DE]
TROUBLE DIAGNOSIS
Revision: 2006 December 2006 FX35/FX45
66 B Sensor ground
(Throttle position sensor) [Engine is running]Warm-up condition
Idle speed
Approximately 0V
67 B/W Sensor ground [Engine is running]
Warm-up condition
Idle speed Approximately 0V
68 BR Sensor power supply
(Power steering pressure
sensor) [Ignition switch: ON]
Approximately 5V
69 R Throttle position sensor 2 [Ignition switch: ON]
Engine stopped
Selector lever: D
Accelerator pedal: Fully released
Less than 4.75V
[Ignition switch: ON]
Engine stopped
Selector lever: D
Accelerator pedal: Fully depressed More than 0.36V
70 L/R Refrigerant pressure sensor [Engine is running]
Warm-up condition
Both A/C switch and blower fan switch: ON
(Compressor operates) 1.0 - 4.0V
73 Y Engine coolant temperature
sensor [Engine is running] Approximately 0 - 4.8V
Output voltage varies with
engine coolant temperature.
74 LG/B Heated oxygen sensor 2
(bank 1) [Engine is running]
Revving engine from idle to 3,000 rpm
quickly after the following conditions are met
–Engine: After warming up.
–After keeping the engine speed between
3,500 and 4,000 rpm for 1 minute and at idle
for 1 minute under no load 0 - Approximately 1.0V
78 B/R Sensor ground
(Heated oxygen sensor) [Engine is running]
Warm-up condition
Idle speed
Approximately 0V
79
80
81 SB
GY
OR Ignition signal No. 6
Ignition signal No. 4
Ignition signal No. 2 [Engine is running]
Warm-up condition
Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idle 0 - 0.2V
[Engine is running]
Warm-up condition
Engine speed: 2,500 rpm 0.1 - 0.4V
TER-
MINAL NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
SEC986C
SEC987C