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Infiniti QX56 (JA60). Manual - part 453

EC-464

< ECU DIAGNOSIS >

[VK56DE]

ECM

Data which are stored in the ECM memory, along with the 1st trip DTC, are called 1st trip freeze frame data.

The data, stored together with the DTC data, are called freeze frame data and displayed on CONSULT-III or

GST. The 1st trip freeze frame data can only be displayed on the CONSULT-III screen, not on the GST. For

details, see

EC-63, "CONSULT-III Function (ENGINE)"

Only one set of freeze frame data (either 1st trip freeze frame data or freeze frame data) can be stored in the

ECM. 1st trip freeze frame data is stored in the ECM memory along with the 1st trip DTC. There is no priority

for 1st trip freeze frame data and it is updated each time a different 1st trip DTC is detected. However, once

freeze frame data (2nd trip detection/MIL on) is stored in the ECM memory, 1st trip freeze frame data is no

longer stored. Remember, only one set of freeze frame data can be stored in the ECM. The ECM has the fol-

lowing priorities to update the data.

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 "HOW TO ERASE EMISSION-

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”.

Priority

Items

Freeze frame data

Misfire — DTC: P0300 - P0308
Fuel Injection System Function — DTC: P0171, P0172, P0174, P0175

Except the above items (Includes A/T related items)

1st trip freeze frame data

SRT item

(CONSULT-III indication)

Performance

Priority*

Required self-diagnostic items to set the SRT to “CMPLT”

Corresponding

DTC No.

CATALYST

Three way catalyst function

P0420, P0430

ECM

EC-465

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[VK56DE]

*: If completion of several SRTs is required, perform driving patterns (DTC confirmation procedure), one by one based on the priority for
models with CONSULT-III.

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.

OK: Self-diagnosis is carried out and the result is OK.
NG: Self-diagnosis is carried out and the result is NG.
—: Self-diagnosis is not carried out.

When all SRT related self-diagnoses showed OK results in a single cycle (Ignition OFF-ON-OFF), the SRT will

indicate “CMPLT”.

→ Case 1 above

When all SRT related self-diagnoses showed OK results through several different cycles, the SRT will indicate

“CMPLT” at the time the respective self-diagnoses have at least one OK result.

→ Case 2 above

If one or more SRT related self-diagnoses showed NG results in 2 consecutive cycles, the SRT will also indi-

cate “CMPLT”.

→ Case 3 above

The table above shows that the minimum number of cycles for setting SRT as “INCMP” is one (1) for each

self-diagnosis (Case 1 & 2) or two (2) for one of self-diagnoses (Case 3). However, in preparation for the state

emissions inspection, it is unnecessary for each self-diagnosis to be executed twice (Case 3) for the following

reasons:

• The SRT will indicate “CMPLT” at the time the respective self-diagnoses have one (1) OK result.

• The emissions inspection requires “CMPLT” of the SRT only with OK self-diagnosis results.

• When, during SRT driving pattern, 1st trip DTC (NG) is detected prior to “CMPLT” of SRT, the self-diagnosis

memory must be erased from ECM after repair.

EVAP SYSTEM

EVAP control system purge flow monitoring

P0441

EVAP control system

P0442

EVAP control system

P0456

HO2S

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

SRT item

(CONSULT-III indication)

Performance

Priority*

Required self-diagnostic items to set the SRT to “CMPLT”

Corresponding

DTC No.

Self-diagnosis result

Example

Diagnosis

Ignition cycle

← ON → OFF

← ON →

All OK

Case 1

P0400

OK (1)

— (1)

OK (2)

— (2)

P0402

OK (1)

— (1)

OK (2)

P1402

OK (1)

OK (2)

— (2)

SRT of EGR

“CMPLT”

Case 2

P0400

OK (1)

— (1)

P0402

— (0)

OK (1)

— (1)

P1402

OK (1)

OK (2)

— (2)

SRT of EGR

“INCMP”

“CMPLT”

NG exists

Case 3

P0400

—

P0402

—

P1402

—

(Consecutive

NG)

(1st trip)

DTC

1st trip DTC

—

1st trip DTC

DTC

(= MIL ON)

SRT of EGR

“INCMP”

“CMPLT”

EC-466

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[VK56DE]

ECM

• If the 1st trip DTC is erased, all the SRT will indicate “INCMP”.

NOTE:

SRT can be set as “CMPLT” together with the DTC(s). Therefore, DTC check must always be carried out

prior to the state emission inspection even though the SRT indicates “CMPLT”.

SRT Service Procedure

If a vehicle has failed the state emissions inspection due to one or more SRT items indicating “INCMP”, review

the flowchart diagnostic sequence on the next page.

How to Display SRT Status

WITH CONSULT-III

Selecting “SRT STATUS” in “DTC CONFIRMATION” mode with CONSULT-III.

For items whose SRT codes are set, a “CMPLT” is displayed on the CONSULT-III screen; for items whose

SRT codes are not set, “INCMP” is displayed.

NOTE:

Though displayed on the CONSULT-III screen, “HO2S HTR” is not SRT item.

WITH GST

Selecting Service $01 with GST (Generic Scan Tool)

*1 "How to Read DTC and 1st Trip DTC" *2 "How to Display SRT Status"

*3 "How to Set SRT Code"

PBIB2320E

ECM

EC-467

< ECU DIAGNOSIS >

[VK56DE]

NO TOOLS

A SRT code itself can not be displayed while only SRT status can be.
1. Turn ignition switch ON and wait 20 seconds.
2. SRT status is indicated as shown below.

• When all SRT codes are set, MIL lights up continuously.

• When any SRT codes are not set, MIL will flash periodically for 10 seconds.

How to Set SRT Code

To set all SRT codes, self-diagnosis for the items indicated above must be performed one or more times. Each

diagnosis may require a long period of actual driving under various conditions.

WITH CONSULT-III

Perform corresponding DTC Confirmation Procedure one by one based on Performance Priority in the table

on "SRT Item".

WITHOUT CONSULT-III

The most efficient driving pattern in which SRT codes can be properly set is explained on the next page. The

driving pattern should be performed one or more times to set all SRT codes.

PBIB2317E

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