2001 INFINITI QX4 ignition

System Description=NBEL0171NATS (Nissan Anti-Theft System) has the following immobilizer functions:
ISince only IVIS (NATS) ignition keys, whose ID nos. have been registered into the ECM and IMMU of IVIS
(NATS), allow the engine to run, operation of a stolen vehicle without an IVIS (NATS) registered key is
prevented by IVIS (NATS).
That is to say, IVIS (NATS) will immobilise the engine if someone tries to start it without the registered key
of IVIS (NATS).
IAll of the originally supplied ignition key IDs (except for card plate key) have been IVIS (NATS) registered.
If requested by the vehicle owner, a maximum of five key IDs can be registered into the IVIS (NATS) com-
ponents.
IThe security indicator blinks when the ignition switch is in ªOFFº or ªACCº position. Therefore, IVIS (NATS)
warns outsiders that the vehicle is equipped with the anti-theft system.
IWhen IVIS (NATS) detects trouble, the security indicator lamp lights up while ignition key is in the ªONº
position.
IIVIS (NATS) trouble diagnoses, system initialization and additional registration of other IVIS (NATS) igni-
tion key IDs must be carried out using CONSULT-II hardware and CONSULT-II IVIS (NATS) software.
When IVIS (NATS) initialization has been completed, the ID of the inserted ignition key is automatically
IVIS (NATS) registered. Then, if necessary, additional registration of other IVIS (NATS) ignition key IDs
can be carried out.
Regarding the procedures of IVIS (NATS) initialization and IVIS (NATS) ignition key ID registration, refer
to CONSULT-II operation manual, IVIS/NVIS.
IWhen servicing a malfunction of the IVIS (NATS) (indicated by lighting up of Security Indicator
Lamp) or registering another IVIS (NATS) ignition key ID no., it is necessary to re-register original
key identification. Therefore, be sure to receive ALL KEYS from vehicle owner.
System CompositionNBEL0172The immobiliser function of the IVIS (NATS) consists of the following:
IIVIS (NATS) ignition key
IIVIS (NATS) immobilizer control unit (IMMU) located in the ignition key cylinder
IEngine control module (ECM)
ISecurity indicator
SEL085WE
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IVIS (INFINITI VEHICLE IMMOBILIZER SYSTEM Ð NATS)
System Description
EL-329

SEL331X
CONSULT-IINBEL0223CONSULT-II INSPECTION PROCEDURENBEL0223S011. Turn ignition switch OFF.
2. Insert IVIS (NATS) program card into CONSULT-II.
: Program card
NATS (UEN99A)
3. Connect CONSULT-II to data link connector.
SEL762W
4. Turn ignition switch ON.
5. Touch ªSTARTº.
SEL851W
6. Select ªNATS V.5.0º.
SEL363X
7. Perform each diagnostic test mode according to each service
procedure.
For further information, see the CONSULT-II Operation
Manual, IVIS/NVIS.
CONSULT-II DIAGNOSTIC TEST MODE FUNCTIONNBEL0223S02
CONSULT-II DIAGNOSTIC TEST
MODEDescription
C/U INITIALIZATION When replacing any of the following three components, C/U initialization and re-registration
of all IVIS (NATS) ignition keys are necessary.
[IVIS (NATS) ignition key/IMMU/ECM]
SELF-DIAG RESULTS Detected items (screen terms) are as shown in the chart EL-332.
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IVIS (INFINITI VEHICLE IMMOBILIZER SYSTEM Ð NATS)
CONSULT-II
EL-331

NOTE:
IWhen any initialization is performed, all ID previously reg-
istered will be erased and all IVIS (NATS) ignition keys
must be registered again.
IThe engine cannot be started with an unregistered key. In this
case, the system will show ªDIFFERENCE OF KEYº or ªLOCK
MODEº as a self-diagnostic result on the CONSULT-II screen.
IIn rare case, ªCHAIN OF ECM-IMMUº might be stored as a
self-diagnostic result during key registration procedure, even if
the system is not malfunctioning.
HOW TO READ SELF-DIAGNOSTIC RESULTSNBEL0223S03
SEL364X
IVIS (NATS) SELF-DIAGNOSTIC RESULTS ITEM CHARTNBEL0223S04
Detected items (NATS program card
screen terms)P No. Code
(Self-diag-
nostic
result of
ªENGINEºMalfunction is detected when .....
Reference page
ECM INT CIRC-IMMUNATS MAL-
FUNCTION
P1613The malfunction of ECM internal circuit of IMMU com-
munication line is detected. EL-336
CHAIN OF ECM-IMMUNATS MAL-
FUNCTION
P1612Communication impossible between ECM and IMMU
(In rare case, ªCHAIN OF ECM-IMMUº might be stored
during key registration procedure, even if the system is
not malfunctioning.)EL-337
DIFFERENCE OF KEYNATS MAL-
FUNCTION
P1615IMMU can receive the key ID signal but the result of ID
verification between key ID and IMMU is NG. EL-341
CHAIN OF IMMU-KEYNATS MAL-
FUNCTION
P1614IMMU cannot receive the key ID signal.
EL-342
ID DISCORD, IMM-ECMNATS MAL-
FUNCTION
P1611The result of ID verification between IMMU and ECM is
NG. System initialization is required. EL-343
IVIS (INFINITI VEHICLE IMMOBILIZER SYSTEM Ð NATS)
CONSULT-II (Cont'd)
EL-332

Detected items (NATS program card
screen terms)P No. Code
(Self-diag-
nostic
result of
ªENGINEºMalfunction is detected when .....
Reference page
LOCK MODENATS MAL-
FUNCTION
P1610When the starting operation is carried out five or more
times consecutively under the following conditions, IVIS
(NATS) will shift the mode to one which prevents the
engine from being started.
IUnregistered ignition key is used.
IIMMU or ECM's malfunctioning.EL-346
DON'T ERASE BEFORE
CHECKING ENG DIAGÐAll engine trouble codes except IVIS (NATS) trouble
code has been detected in ECM.EL-334GI
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IVIS (INFINITI VEHICLE IMMOBILIZER SYSTEM Ð NATS)
CONSULT-II (Cont'd)
EL-333

SYMPTOM MATRIX CHART 1NBEL0224S02(Self-diagnosis related item)
SYMPTOMDisplayed ªSELF-DIAG
RESULTSº on CON-
SULT-II screen.DIAGNOSTIC PROCE-
DURE
(Reference page)SYSTEM
(Malfunctioning part or
mode)REFERENCE PART NO.
OF ILLUSTRATION ON
NEXT PAGE
ISecurity indicator
lighting up*
IEngine cannot be
started.ECM INT CIRC-IMMUPROCEDURE 1
(EL-336)ECM B
CHAIN OF ECM-IMMUPROCEDURE 2
(EL-337)In rare case, ªCHAIN
OF ECM-IMMUº might
be stored during key
registration procedure,
even if the system is
not malfunctioning.Ð
Open circuit in battery
voltage line of IMMU
circuitC1
Open circuit in ignition
line of IMMU circuitC2
Open circuit in ground
line of IMMU circuitC3
Open circuit in commu-
nication line between
IMMU and ECMC4
Short circuit between
IMMU and ECM com-
munication line and bat-
tery voltage lineC4
Short circuit between
IMMU and ECM com-
munication line and
ground lineC4
ECM B
IMMU A
DIFFERENCE OF KEYPROCEDURE 3
(EL-341)Unregistered key D
IMMU A
CHAIN OF IMMU-KEYPROCEDURE 4
(EL-342)Malfunction of key ID
chipE
IMMU A
ID DISCORD, IMM-
ECMPROCEDURE 5
(EL-343)System initialization has
not yet been com-
pleted.F
ECM F
LOCK MODEPROCEDURE 7
(EL-346)LOCK MODE D
IMIL staying ON
ISecurity indicator
lighting up*DON'T ERASE
BEFORE CHECKING
ENG DIAGWORK FLOW
(EL-334)Engine trouble data and
IVIS (NATS) trouble
data have been
detected in ECMÐ
*: When IVIS (NATS) detects trouble, the security indicator lights up while ignition key is in the ªONº position.
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IVIS (INFINITI VEHICLE IMMOBILIZER SYSTEM Ð NATS)
Trouble Diagnoses (Cont'd)
EL-335

3 CHECK IGN SW. ON SIGNAL
1. Turn ignition switch ON.
2. Check voltage between terminal 7 of IMMU and ground with CONSULT-II or tester.
SEL303WF
OK or NG
OK©GO TO 4.
NG©Check the following
I10A fuse [No. 16, located in the fuse block (J/B)]
IHarness for open or short between fuse and IMMU connector
Ref. part No. C2
4 CHECK GROUND CIRCUIT FOR IMMU
1. Turn ignition OFF.
2. Check harness continuity between IMMU terminal 4 and ground.
SEL304WD
OK or NG
OK©GO TO 5.
NG©Repair harness.Ref. part No. C3
IVIS (INFINITI VEHICLE IMMOBILIZER SYSTEM Ð NATS)
Trouble Diagnoses (Cont'd)
EL-338

5 CHECK COMMUNICATION LINE OPEN CIRCUIT
1. Disconnect ECM connector.
2. Check harness continuity between ECM terminal 116 and IMMU terminal 1.
SEL305WD
OK or NG
OK©GO TO 6.
NG©Repair harness or connector.
Ref. part No. C4
6 CHECK COMMUNICATION LINE BATTERY SHORT CIRCUIT
1. Turn ignition ON.
2. Check voltage between ECM terminal 116 or IMMU terminal 1 and ground.
SEL306WD
OK or NG
OK©GO TO 7.
NG©Communication line is short-circuited with battery voltage line or ignition switch ON line.
Repair harness or connectors.
Ref. part No. C4
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IVIS (INFINITI VEHICLE IMMOBILIZER SYSTEM Ð NATS)
Trouble Diagnoses (Cont'd)
EL-339

7 CHECK COMMUNICATION LINE GROUND SHORT CIRCUIT
1. Turn ignition switch OFF.
2. Check continuity between ECM terminal 116 or IMMU terminal 1 and ground.
SEL307WD
OK or NG
OK©GO TO 8.
NG©Communication line is short-circuited with ground line.
Repair harness or connectors.
Ref. part No. C4
8 SIGNAL FROM ECM TO IMMU CHECK
1. Check the signal between ECM terminal 116 and ground with CONSULT-II or oscilloscope when ignition switch is
turned ªONº.
2. Make sure signals which are shown in the figure below can be detected during 750 msec. just after ignition switch is
turned ªONº.
SEL730W
OK or NG
OK©IMMU is malfunctioning.
Replace IMMU.Ref. part No. A
Perform initialization with CONSULT-II.
For the operation of initialization, refer to ªCONSULT-II Operation Manual IVIS/NVISº.
NG©ECM is malfunctioning.
Replace ECM.Ref. part No. B
Perform initialization with CONSULT-II.
For the operation of initialization, refer to ªCONSULT-II Operation Manual IVIS/NVISº.
IVIS (INFINITI VEHICLE IMMOBILIZER SYSTEM Ð NATS)
Trouble Diagnoses (Cont'd)
EL-340