UNIFIED METER AND A/C AMP
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Revision: 2004 November 2004 FX35/FX45
FA I L - S A F E
Solution When Communication Error Between the Unified Meter & A/C Amp. and the Combi-
nation Meter
CAN Communication System DescriptionAKS007Z1
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.
CAN Communication UnitAKS007YX
Refer to LAN-6, "CAN Communication Unit" in “LAN SYSTEM”.
Function Specifications
Speedometer
Reset to zero by suspending communication. Tachometer
Fuel gauge
Water temperature gauge
Illumination control Combination meter illumination When suspending communication, change to nighttime mode.
Odo/trip meter Integrate in response to 8-pulse input.
A/T position indicator The display turns off by suspending communication.
Warning buzzer The warning buzzer turns off by suspending communication.
Warning lamp/indicator lampABS warning lamp
The lamp turns on by suspending communication. VDC OFF indicator
SLIP indicator
Brake warning lamp
Door warning lamp
The lamp turns off by suspending communication. Low tire pressure warning lamp
ASCD SET indicator lamp
ASCD CRUISE indicator lamp
AWD warning lamp
ICC warning lamp
A/T CHECK warning lamp
Oil pressure warning lamp
Snow mode indicator lamp
Turn signal indicator
Malfunction indicator lamp
High beam indicator
EC-32
[VQ35DE]
ENGINE CONTROL SYSTEM
Revision: 2004 November 2004 FX35/FX45
Multiport Fuel Injection (MFI) SystemABS006K7
INPUT/OUTPUT SIGNAL CHART
*1: This sensor is not used to control the engine system under normal conditions.
*2: This signal is sent to the ECM through CAN communication line.
*3: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
The amount of fuel injected from the fuel injector is determined by the ECM. The ECM controls the length of
time the valve remains open (injection pulse duration). The amount of fuel injected is a program value in the
ECM memory. The program value is preset by engine operating conditions. These conditions are determined
by input signals (for engine speed and intake air) from both the crankshaft position sensor and the mass air
flow sensor.
VARIOUS FUEL INJECTION INCREASE/DECREASE COMPENSATION
In addition, the amount of fuel injected is compensated to improve engine performance under various operat-
ing conditions as listed below.
During warm-up
When starting the engine
During acceleration
Hot-engine operation
When selector lever is changed from N to D
High-load, high-speed operation
During deceleration
During high engine speed operation
Sensor Input Signal to ECM ECM function Actuator
Crankshaft position sensor (POS)
Engine speed*
3
Piston position
Fuel injection
& mixture ratio
controlFuel injector Camshaft position sensor (PHASE)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Heated oxygen sensor 1 Density of oxygen in exhaust gas
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Park/neutral position (PNP) switch Gear position
Knock sensor Engine knocking condition
Battery
Battery voltage*
3
Power steering pressure sensor Power steering operation
Heated oxygen sensor 2*
1Density of oxygen in exhaust gas
Air conditioner switch*
2Air conditioner operation
Wheel sensor*
2Vehicle speed
ENGINE CONTROL SYSTEM
EC-33
[VQ35DE]
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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 heated oxy-
gen 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 heated oxygen
sensor 1, refer to EC-205
. 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 heated oxygen 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 heated oxygen sensor 1 or its circuit
Insufficient activation of heated oxygen 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 heated oxygen
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., 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 heated oxygen sensor 1 indicates whether the mixture ratio is RICH or LEAN compared
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.
PBIB0121E
ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-59
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Revision: 2004 November 2004 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 Mode 1 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.
Priority Items
1Freeze frame data Misfire — DTC: P0300 - P0306
Fuel Injection System Function — DTC: P0171, P0172, P0174, P0175
2 Except the above items (Includes A/T related items)
3 1st trip freeze frame data
EC-70
[VQ35DE]
ON BOARD DIAGNOSTIC (OBD) SYSTEM
Revision: 2004 November 2004 FX35/FX45
HOW TO SWITCH DIAGNOSTIC TEST MODE
NOTE:
It is better to count the time accurately with a clock.
It is impossible to switch the diagnostic mode when an accelerator pedal position sensor circuit
has a malfunction.
Always ECM returns to Diagnostic Test Mode I after ignition switch is turned OFF.
How to Set Diagnostic Test Mode II (Self-Diagnostic Results)
1. Confirm that accelerator pedal is fully released, turn ignition switch ON and wait 3 seconds.
2. Repeat the following procedure quickly five times within 5 seconds.
a. Fully depress the accelerator pedal.
b. Fully release the accelerator pedal.
3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the MIL starts
blinking.
4. Fully release the accelerator pedal.
ECM has entered to Diagnostic Test Mode II (Self-diagnostic results).
How to Set Diagnostic Test Mode II (Heated Oxygen Sensor 1 Monitor)
1. Set the ECM in Diagnostic Test Mode II (Self-diagnostic results). Refer to EC-70, "How to Set Diagnostic
Test Mode II (Self-Diagnostic Results)" .
2. Start Engine.
ECM has entered to Diagnostic Test Mode II (Heated oxygen sensor 1 monitor).
ECM will start heated oxygen sensor 1 monitoring from the bank 1 sensor.
How to Switch Monitored Sensor From Bank 1 to Bank 2 or Vice Versa
1. Fully depress the accelerator pedal quickly and then release it immediately.
2. Make sure that monitoring sensor has changed by MIL blinking as follows.
How to Erase Diagnostic Test Mode II (Self-Diagnostic Results)
1. Set ECM in Diagnostic Test Mode II (Self-diagnostic results). Refer to EC-70, "How to Set Diagnostic Test
Mode II (Self-Diagnostic Results)" .
2. Fully depress the accelerator pedal and keep it for more than 10 seconds.
The emission-related diagnostic information has been erased from the backup memory in the ECM.
3. Fully release the accelerator pedal, and confirm the DTC 0000 is displayed.
PBIB0092E
PBIB0093E
ON BOARD DIAGNOSTIC (OBD) SYSTEM
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DIAGNOSTIC TEST MODE I — BULB CHECK
In this mode, the MIL on the instrument panel should stay ON. If it remains OFF, check the bulb. Refer to DI-
39, "WARNING LAMPS" or see EC-641 .
DIAGNOSTIC TEST MODE I — MALFUNCTION WARNING
This DTC number is clarified in Diagnostic Test Mode II (SELF-DIAGNOSTIC RESULTS)
DIAGNOSTIC TEST MODE II — SELF-DIAGNOSTIC RESULTS
In this mode, the DTC and 1st trip DTC are indicated by the number of blinks of the MIL as shown below.
The DTC and 1st trip DTC are displayed at the same time. If the MIL does not illuminate in diagnostic test
mode I (Malfunction warning), all displayed items are 1st trip DTCs. If only one code is displayed when the MIL
illuminates in diagnostic test mode II (SELF-DIAGNOSTIC RESULTS), it is a DTC; if two or more codes are
displayed, they may be either DTCs or 1st trip DTCs. DTC No. is same as that of 1st trip DTC. These uniden-
tified codes can be identified by using the CONSULT-II or GST. A DTC will be used as an example for how to
read a code.
A particular trouble code can be identified by the number of four-digit numeral flashes. The “zero” is indicated
by the number of ten flashes. The length of time the 1,000th-digit numeral flashes on and off is 1.2 seconds
consisting of an ON (0.6-second) - OFF (0.6-second) cycle.
The 100th-digit numeral and lower digit numerals consist of a 0.3-second ON and 0.3-second OFF cycle.
A change from one digit numeral to another occurs at an interval of 1.0-second OFF. In other words, the later
numeral appears on the display 1.3 seconds after the former numeral has disappeared.
A change from one trouble code to another occurs at an interval of 1.8-second OFF.
In this way, all the detected malfunctions are classified by their DTC numbers. The DTC 0000 refers to no mal-
function. (See EC-15, "
INDEX FOR DTC" )
How to Erase Diagnostic Test Mode II (Self-Diagnostic Results)
The DTC can be erased from the back up memory in the ECM by depressing accelerator pedal. Refer to EC-
70, "How to Set Diagnostic Test Mode II (Self-Diagnostic Results)" .
If the battery is disconnected, the DTC will be lost from the backup memory within 24 hours.
Be careful not to erase the stored memory before starting trouble diagnoses.
DIAGNOSTIC TEST MODE II — HEATED OXYGEN SENSOR 1 MONITOR
In this mode, the MIL displays the condition of the fuel mixture (lean or rich) which is monitored by the heated
oxygen sensor 1.
MIL Condition
ON When the malfunction is detected.
OFF No malfunction.
PBIA3905E
EC-118
[VQ35DE]
TROUBLE DIAGNOSIS
Revision: 2004 November 2004 FX35/FX45
NOTE:
Any monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
DATA MONITOR (SPEC) MODE
Monitored Item
NOTE:
Any monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
ACTIVE TEST MODE
Test Item
Voltage [V]
Voltage, frequency, duty cycle or pulse
width measured by the probe.
Only # is displayed if item is unable
to be measured.
Figures with #s are temporary ones.
They are the same figures as an
actual piece of data which was just
previously measured. Frequency [msec],
[Hz] or [%]
DUTY-HI
DUTY-LOW
PLS WIDTH-HI
PLS WIDTH-LOWMonitored item [Unit]ECM
INPUT
SIG-
NALSMAIN
SIG-
NALSDescription Remarks
Monitored item [Unit]ECM
input
signalsMain
signalsDescription Remarks
ENG SPEED [rpm]××
Indicates the engine speed computed
from the signal of the crankshaft position
sensor (POS) and camshaft position
sensor (PHASE).
MAS A/F SE-B1 [V]××
The signal voltage of the mass air flow
sensor specification is displayed.When engine is running specification
range is indicated.
B/FUEL SCHDL
[msec]×
Base fuel schedule indicates the fuel
injection pulse width programmed into
ECM, prior to any learned on board cor-
rection.
When engine is running specification
range is indicated.
A/F ALPHA-B1 [%]
A/F ALPHA-B2 [%]×
The mean value of the air-fuel ratio feed-
back correction factor per cycle is indi-
cated.When engine is running specification
range is indicated.
This data also includes the data for the
air-fuel ratio learning control.
TEST ITEM CONDITION JUDGEMENT CHECK ITEM (REMEDY)
FUEL INJEC-
TION
Engine: Return to the original
trouble condition
Change the amount of fuel injec-
tion using CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.
Harness and connectors
Fuel injector
Heated oxygen sensor 1
IGNITION TIM-
ING
Engine: Return to the original
trouble condition
Timing light: Set
Retard the ignition timing using
CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.
Perform Idle Air Volume Learning.
POWER BAL-
ANCE
Engine: After warming up, idle
the engine.
A/C switch: OFF
Shift lever: P or N
Cut off each injector signal one at
a time using CONSULT-II.Engine runs rough or dies.
Harness and connectors
Compression
Fuel injector
Power transistor
Spark plug
Ignition coil
TROUBLE DIAGNOSIS
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REAL TIME DIAGNOSIS IN DATA MONITOR MODE (RECORDING VEHICLE DATA)
Description
CONSULT-II has two kinds of triggers and they can be selected by touching “SETTING” in “DATA MONITOR”
mode.
1. “AUTO TRIG” (Automatic trigger):
The malfunction will be identified on the CONSULT-II screen
in real time.
In other words, DTC/1st trip DTC and malfunction item will be
displayed if the malfunction is detected by ECM.
At the moment a malfunction is detected by ECM, “MONI-
TOR” in “DATA MONITOR” screen is changed to “Recording
Data... xx%” as shown at right, and the data after the malfunc-
tion detection is recorded. Then when the percentage
reached 100%, “REAL-TIME DIAG” screen is displayed. If
“STOP” is touched on the screen during “Recording Data...
xx%”, “REAL-TIME DIAG” screen is also displayed.
The recording time after the malfunction detection and the
recording speed can be changed by “TRIGGER POINT” and
“Recording Speed”. Refer to CONSULT-II OPERATION MAN-
UAL.
2. “MANU TRIG” (Manual trigger):
DTC/1st trip DTC and malfunction item will not be displayed
automatically on CONSULT-II screen even though a malfunc-
tion is detected by ECM.
DATA MONITOR can be performed continuously even though
a malfunction is detected.
SEF705Y
SEF707X