DTC P1777 STEP MOTOR - CIRCUIT
CVT-155
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CVT
TCM terminals data are reference values.
Diagnostic ProcedureBCS001LY
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Start engine.
2. Select “SELECTION FROM MENU” in “DATA MONITOR” mode
for “TRANSMISSION” with CONSULT-II.
3. Start vehicle and read out the value of “STM STEP”, “SMCOIL
A”, “SMCOIL B”, “SMCOIL C”, and “SMCOIL D”.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2. CHECK HARNESS BETWEEN TCM AND STEP MOTOR
1. Turn ignition switch OFF.
2. Disconnect CVT unit connector and TCM connector.
3. Check continuity between TCM connector terminals and CVT
unit harness connector terminals.
4. If OK, check harness for short to ground and short to power.
5. If OK, check continuity between body ground and CVT assembly.
6. Reinstall any part removed.
OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
Terminal Wire color Item Condition Data (Approx.)
11 G/R Step motor A Within 2 seconds after ignition switch ON, the time measure-
ment by using the pulse width measurement function (Hi level) of
CONSULT-II.*1
CAUTION:
Connect the diagnosis data link cable to the vehicle diagno-
sis connector.
*1: A circuit tester cannot be used to test this item.30.0 msec
12 O/B Step motor B10.0 msec
20 R Step motor C30.0 msec
21 R/G Step motor D10.0 msec
Item name Condition Display value (Approx.)
STM STEP
During driving−20 step - 190 step
SMCOIL A
Changes ON⇔OFF SMCOIL B
SMCOIL C
SMCOIL D
SCIA4516E
Item Connector Terminal Continuity
TCM F106 11
Ye s
CVT unit harness connector F49 6
TCM F106 12
Ye s
CVT unit harness connector F49 7
TCM F106 20
Ye s
CVT unit harness connector F49 8
TCM F106 21
Ye s
CVT unit harness connector F49 9
SCIA4695E
COMBINATION METERS
DI-5
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FA I L - S A F E
Solution When Communication Error Between the Unified Meter and A/C Amp. and the Com-
bination Meter
Function Specifications
SpeedometerReturn to zero when discontinuing communication or receiv-
ing irregular data.
Tachometer
Reset to zero by suspending communication.
Fuel gauge
Illumination control Combination meter illumination When suspending communication, change to nighttime mode.
Odo/trip meter Integrate in response to 8-pulse input.
Shift indicator The display turns off by suspending communication.
Warning buzzer The warning buzzer turns off by suspending communication.
Warning lamp/indicator lampLow water temperature indicator lamp
The lamp turns on by suspending communication. VDC OFF indicator (With VDC)
SLIP indicator (With VDC)
Brake warning lamp
ABS warning lamp
ASCD CRUISE indicator lamp
The lamp turns off by suspending communication. ASCD SET indicator lamp
Turn signal indicator lamp
High-beam indicator lamp
Front fog indicator lamp
Rear fog indicator lamp
Oil pressure warning lamp
Door warning lamp
High water temperature warning lamp
Malfunction indicator lamp
A/T CHECK warning lamp
CVT indicator lamp
KEY warning lamp
LOCK warning lamp
DI-6
COMBINATION METERS
HOW TO CHANGE THE DISPLAY FOR ODO/TRIP METER
The vehicle speed signal and the memory signals from the meter memory circuit are processed by the
combination meter and the mileage is displayed.
Depressing the odo/trip meter switch toggles the mode in the following order.
The odo/trip meter display mode toggling and trip display resetting can be identified by the amount of time
that elapses from pressing the odo/trip meter switch to releasing it.
When resetting with trip A displayed, only trip A display is reset (The same way for “trip B”).
POWER SUPPLY AND GROUND CIRCUIT
Power is supplied at all times
through 10A fuse [No. 19, located in the fuse block (J/B)]
to unified meter and A/C amp. terminal 21,
through 15A fuse [No. 17, located in the fuse block (J/B)]
to combination meter terminal 7.
With the ignition switch in the ACC or ON position, power is supplied
through 10A fuse [No. 6, located in the fuse block (J/B)]
to unified meter and A/C amp. terminal 35.
With the ignition switch in the ON or START position, power is supplied
through 10A fuse [No. 14, located in the fuse block (J/B)]
to combination meter terminal 8,
through 10A fuse [No. 12, located in the fuse block (J/B)]
to unified meter and A/C amp. terminal 22.
With the ignition switch in the ON position, power is supplied
through 15A fuse [No. 10, located in the fuse block (J/B)], and
through 15A fuse [No. 11, located in the fuse block (J/B)]
to unified meter and A/C amp. terminal 46.
Ground is supplied
to combination meter terminals 10, 11 and 12
through body grounds M71 and M72,
to unified meter and A/C amp. terminals 29 and 30
through body grounds M71 and M72.
SEL175W
ENGINE CONTROL SYSTEM
EC-21
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EC
Multiport Fuel Injection (MFI) SystemBBS005BF
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)
Camshaft position sensor (PHASE)Engine speed*
3
Piston position
Fuel injection & mixture
ratio controlFuel injector 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
Wheel sensor
Vehicle speed*
2
Air conditioner switch
Air conditioner operation*2
EC-22
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ENGINE CONTROL SYSTEM
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 (manifold) can then better reduce CO, HC and NOx emissions. This system uses
heated oxygen 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-143
. 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 (manifold). Even if the switching
characteristics 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., 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 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.
PBIB2953E
ON BOARD DIAGNOSTIC (OBD) SYSTEM
EC-39
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EC
played, they may be either DTCs or 1st trip DTCs. DTC No. is same as that of 1st trip DTC. These unidentified
codes can be identified by using the CONSULT-II. 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-10, "
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-
37, "HOW TO SWITCH DIAGNOSTIC TEST MODE" .
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 MI displays the condition of the fuel mixture (lean or rich) which is monitored by the heated
oxygen sensor 1.
*: Maintains conditions just before switching to open loop.
To check the heated oxygen sensor 1 function, start engine in the Diagnostic Test Mode II and warm it up until
engine coolant temperature indicator points to the middle of the gauge.
Next run engine at about 2,000 rpm for about 2 minutes under no-load conditions. Then make sure that the MI
comes ON more than 5 times within 10 seconds with engine running at 2,000 rpm under no-load.
PBIA3905E
MI Fuel mixture condition in the exhaust gas Air fuel ratio feedback control condition
ON Lean
Closed loop system
OFF Rich
*Remains ON or OFF Any condition Open loop system
EC-86
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TROUBLE DIAGNOSIS
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
Monitored item [Unit]ECM
INPUT
SIGNALSMAIN
SIGNALSDescription Remarks
ENG SPEED [rpm]×
Indicates the engine speed computed
from the signals of the crankshaft posi-
tion 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 [%]×
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.
Air conditioner switch OFF
Shift lever: P or N
Cut off each fuel 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
COOLING FAN*
Ignition switch: ON
Turn the cooling fan LOW, MID,
HI, OFF with CONSULT-II.Cooling fan moves and stops.
Harness and connectors
Cooling fan motor
IPDM E/R
ENG COOLANT
TEMP
Engine: Return to the original
trouble condition
Change the engine coolant tem-
perature using CONSULT-II.If trouble symptom disappears, see
CHECK ITEM.
Harness and connectors
Engine coolant temperature sen-
sor
Fuel injector
FUEL PUMP
RELAY
Ignition switch: ON (Engine
stopped)
Turn the fuel pump relay ON and
OFF using CONSULT-II and lis-
ten to operating sound.Fuel pump relay makes the operat-
ing sound.Harness and connectors
Fuel pump relay
EC-88
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TROUBLE DIAGNOSIS
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 mal-
function 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 Manual.
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.
Operation
1. “AUTO TRIG”
While trying to detect the DTC/1st trip DTC by performing the DTC Confirmation Procedure, be sure to
select to “DATA MONITOR (AUTO TRIG)” mode. You can confirm the malfunction at the moment it is
detected.
While narrowing down the possible causes, CONSULT-II should be set in “DATA MONITOR (AUTO
TRIG)” mode, especially in case the incident is intermittent.
When you are inspecting the circuit by gently shaking (or twisting) the suspicious connectors, compo-
nents and harness in the “DTC Confirmation Procedure”, the moment a malfunction is found the DTC/
1st trip DTC will be displayed. (Refer to “Incident Simulation Tests” in GI-24, "
How to Perform Efficient
Diagnosis for an Electrical Incident" .)
2. “MANU TRIG”
If the malfunction is displayed as soon as “DATA MONITOR” is selected, reset CONSULT-II to “MANU
TRIG”. By selecting “MANU TRIG” you can monitor and store the data. The data can be utilized for fur-
ther diagnosis, such as a comparison with the value for the normal operating condition.
SEF705Y
SEF707X