Infiniti Q45 (FY33). Manual — part 148
SEF961X
SEF370U
INSPECTION START
Start engine.
Is engine running?
No
E
Yes
Go to
“CHECK
POWER SUPPLY-II” on
next page.
CHECK IGNITION SIGNAL CIRCUIT.
1. Turn ignition switch “ON”.
2. Select “SELF-DIAG RESULTS”
mode with CONSULT-II.
3. Turn ignition switch to “START”
for at least 5 seconds.
Is the (1st trip) DTC P1320
detected?
-------------------------------------------------------------------------------------------------------------------------------------- OR --------------------------------------------------------------------------------------------------------------------------------------
1. Turn ignition switch to “START”
for at least 5 seconds.
2. Perform “Diagnostic Test Mode
II (Self-diagnostic results)” with
ECM.
Is the DTC 0201 detected?
No
E
Yes
Go to “TROUBLE DIAG-
NOSIS FOR P1320”, EC-399.
CHECK POWER SUPPLY-I.
1. Turn ignition switch “ON”.
2. Check voltage between ECM terminal
q
78
and ground with CONSULT-II or
tester.
Voltage: Battery voltage
OK
E
NG
Check the following.
I
Harness connectors
M49
,
F63
I
15A fuse
I
Harness for open or
short between ECM and
fuse
If NG, repair harness or
connectors.
Go to
“CHECK GROUND CIRCUIT”,
on EC-123.
GI
MA
EM
LC
FE
AT
PD
FA
RA
BR
ST
RS
BT
HA
EL
IDX
TROUBLE DIAGNOSIS FOR POWER SUPPLY
Main Power Supply and Ground Circuit
(Cont’d)
H
H
H
H
EC-121
SEF371U
SEF372U
SEF393WB
SEF890V
SEF891V
CHECK POWER SUPPLY-II.
1. Stop engine.
2. Check voltage between ECM terminals
q
56
,
123
and ground with CONSULT-II
or tester.
Voltage: Battery voltage
OK
E
NG
Check the following.
I
Harness connectors
F2
,
E13
I
Harness connectors
F1
,
E14
I
7.5A fuse
I
10A fuse
I
Harness for open or
short between ECM and
battery
If NG, repair harness or
connectors.
CHECK POWER SUPPLY-III.
1. Turn ignition switch “ON” and then turn
“OFF”.
2. Check voltage between ECM terminals
130
,
131
and ground with CON-
SULT-II or tester.
Voltage:
After turning ignition switch “OFF”,
battery voltage will exist for a few
seconds, then drop to approximately
0V.
NG
E
OK
Go to
“CHECK ECM
RELAY” on next page.
Case-1: Battery voltage does
not exist.
Case-2: Battery voltage exists
for more than a few
seconds.
Case-1
E
Case-2
Go to
“CHECK ECM
RELAY” on next page.
CHECK HARNESS CONTINUITY
BETWEEN ECM RELAY AND ECM.
1. Disconnect ECM harness connector.
2. Disconnect ECM relay.
3. Check harness continuity between ECM
terminals
130
,
131
and terminal
q
3
.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
E
NG
Repair open circuit or short
to ground or short to power
in harness or connectors.
CHECK VOLTAGE BETWEEN ECM
RELAY AND GROUND.
1. Check voltage between terminals
q
2
,
q
5
and ground with CONSULT-II or
tester.
Voltage: Battery voltage
OK
E
NG
Check the following.
I
Harness for open or
short between ECM relay
and harness connector
F2
If NG, repair harness or
connectors.
q
A
(Go to next page.)
TROUBLE DIAGNOSIS FOR POWER SUPPLY
Main Power Supply and Ground Circuit
(Cont’d)
H
H
H
H
EC-122
SEF892V
SEC202B
SEF461U
q
A
CHECK OUTPUT SIGNAL CIRCUIT.
1. Check harness continuity between ECM
terminal
124
and relay terminal
q
1
.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
E
NG
Repair open circuit or short
to ground or short to power
in harness or connectors.
CHECK ECCS RELAY.
1. Apply 12V direct current between relay
terminals
q
1
and
q
2
.
2. Check continuity between relay termi-
nals
q
3
and
q
5
,
q
6
and
q
7
.
12V (
q
1
-
q
2
) applied:
Continuity exists.
No voltage applied:
No continuity
OK
E
NG
Replace ECM relay.
CHECK GROUND CIRCUIT.
1. Turn ignition switch “OFF”.
2. Loosen and retighten engine ground
screws.
3. Disconnect ECM harness connector.
4. Check harness continuity between ECM
terminals
121
,
122
,
125
,
126
,
127
,
128
and engine ground.
Continuity should exist.
If OK, check harness for short to power.
OK
E
NG
Check the following.
I
Harness connectors
F61
,
F62
I
Harness for open or
short between engine
grounds
F24
and
F25
If NG, repair open circuit or
short to power in harness
or connectors.
Perform “TROUBLE DIAGNOSIS FOR
INTERMITTENT INCIDENT”, EC-117.
INSPECTION END
GI
MA
EM
LC
FE
AT
PD
FA
RA
BR
ST
RS
BT
HA
EL
IDX
TROUBLE DIAGNOSIS FOR POWER SUPPLY
Main Power Supply and Ground Circuit
(Cont’d)
H
H
H
H
H
EC-123
SEF260Q
Mass Air Flow Sensor (MAFS)
COMPONENT DESCRIPTION
The mass air flow sensor is placed in the stream of intake air. It
measures the intake flow rate by measuring a part of the entire
intake flow. It consists of a hot film that is supplied with electric
current from the ECM. The temperature of the hot film is controlled
by the ECM a certain amount. The heat generated by the hot film
is reduced as the intake air flows around it. The more air, the
greater the heat loss.
Therefore, the ECM must supply more electric current to the hot
film as air flow increases. This maintains the temperature of the hot
film. The ECM detects the air flow by means of this current change.
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Specification data are reference values.
MONITOR ITEM
CONDITION
SPECIFICATION
MAS AIR/FL SE
I
Engine: After warming up
I
Air conditioner switch: “OFF”
I
Shift lever: “N”
I
No-load
Idle
1.0 - 1.7V
2,500 rpm
Approximately 2.1V
CAL/LD VALUE
I
Engine: After warming up
I
Air conditioner switch: “OFF”
I
Shift lever: “N”
I
No-load
Idle
13.0 - 32%
2,500 rpm
13.0 - 25.5%
MASS AIRFLOW
I
Engine: After warming up
I
Air conditioner switch: “OFF”
I
Shift lever: “N”
I
No-load
Idle
3.0 - 6.0 g
⋅
m/s
2,500 rpm
12.9 - 25.3 g
⋅
m/s
ECM TERMINALS AND REFERENCE VALUE
Specification data are reference values, and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring voltage. Doing so may result in damage to the
ECM’s transistor. Use a ground other than ECM terminals such as the body ground.
TER-
MINAL
NO.
WIRE
COLOR
ITEM
CONDITION
DATA
(DC voltage)
65
W
Mass air flow sensor
Engine is running. (Warmed-up condition)
Idle speed
1.0 - 1.7V
Engine is running. (Warmed-up condition)
Engine speed is 2,500 rpm.
Approximately 2.1V
62
B
Mass air flow sensor
ground
Engine is running. (Warmed-up condition)
Idle speed
Approximately 0V
ON BOARD DIAGNOSTIC LOGIC
Diagnostic
Trouble
Code No.
Malfunction is detected when ...
Check Items
(Possible Cause)
P0100
0102
A) An excessively high voltage from the sensor is sent to ECM
when engine is not running.*
. . . . . . . . . . . . . . . . . . . . . . . . . .
C) A high voltage from the sensor is sent to ECM under light
load driving conditions.
I
Harness or connectors
(The sensor circuit is open or shorted.)
I
Mass air flow sensor
B) An excessively low voltage from the sensor is sent to ECM*
when engine is running.
. . . . . . . . . . . . . . . . . . . . . . . . . .
D) A low voltage from the sensor is sent to ECM under heavy
load driving conditions.
I
Harness or connectors
(The sensor circuit is open or shorted.)
I
Intake air leaks
I
Mass air flow sensor
*: When the malfunction is detected, the ECM enters fail-safe mode and the MIL lights up. (Refer to EC-98.)
Engine operating condition in fail-safe mode
Engine speed will not rise more than 2,400 rpm due to the fuel cut.
TROUBLE DIAGNOSIS FOR DTC P0100
EC-124
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