Emission-related Diagnostic Information
NCEC0031
DTC AND 1ST TRIP DTC
NCEC0031S01
The 1st trip DTC (whose number is the same as the DTC number) is displayed for the latest self-diagnostic
result obtained. If the ECM memory was cleared previously, and the 1st trip DTC did not reoccur, the 1st trip
DTC will not be displayed. If a malfunction is detected during the 1st trip, the 1st trip DTC is stored in the ECM
memory. The MI will not light up (two trip detection logic). If the same malfunction is not detected in the 2nd
trip (meeting the required driving pattern), the 1st trip DTC is cleared from the ECM memory. If the same mal-
function is detected in the 2nd trip, both the 1st trip DTC and DTC are stored in the ECM memory and the MI
lights up. In other words, the DTC is stored in the ECM memory and the MI lights up when the same malfunc-
tion occurs in two consecutive trips. If a 1st trip DTC is stored and a non-diagnostic operation is performed
between the 1st and 2nd trips, only the 1st trip DTC will continue to be stored. For malfunctions that blink or
light up the MI during the 1st trip, the DTC and 1st trip DTC are stored in the ECM memory.
Procedures for clearing the DTC and the 1st trip DTC from the ECM memory are described in “HOW TO
ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION”. Refer to EC-QG-44.
For malfunctions in which 1st trip DTCs are displayed, refer to EC-QG-42. These items are required by legal
regulations to continuously monitor the system/component. In addition, the items monitored non-continuously
are also displayed on CONSULT-II.
1st trip DTC is specified in Mode 7 of ISO15031-5. 1st trip DTC detection occurs without lighting up the MI
and therefore does not warn the driver of a problem. However, 1st trip DTC detection will not prevent the
vehicle from being tested, for example during Inspection/Maintenance (I/M) tests.
When a 1st trip DTC is detected, check, print out or write down and erase (1st trip) DTC and Freeze Frame
data as specified in “Work Flow” procedure Step II, refer to page EC-QG-70. Then perform “DTC Confirma-
tion Procedure” or “Overall Function Check” to try to duplicate the problem. If the malfunction is duplicated,
the item requires repair.
How to read DTC and 1st Trip DTC
NCEC0031S0101
DTC and 1st trip DTC can be read by the following methods.
1)
No Tools
The number of blinks of MI in the Diagnostic Test Mode II (Self-Diagnostic Results) Examples: 0340, 1320,
0705, 0750, etc.
These DTCs are controlled by NISSAN.
2)
With CONSULT-II
With GST
CONSULT-II or GST (Generic Scan Tool) Examples: P0340, P1320, P0705, P0750, etc.
These DTCs are prescribed by ISO15031-6.
(CONSULT-II also displays the malfunctioning component or system.)
I
1st trip DTC No. is the same as DTC No.
I
Output of a DTC indicates a malfunction. However, Mode II and GST do not indicate whether the
malfunction is still occurring or has occurred in the past and has returned to normal.
CONSULT-II can identify malfunction status as shown below. Therefore, using CONSULT-II (if avail-
able) is recommended.
A sample of CONSULT-II display for DTC is shown below. DTC or 1st trip DTC of a malfunction is displayed
in SELF-DIAGNOSTIC RESULTS mode of CONSULT-II. Time data indicates how many times the vehicle was
driven after the last detection of a DTC.
If the DTC is being detected currently, the time data will be “0”.
If a 1st trip DTC is stored in the ECM, the time data will be “[1t]”.
NEF065A
DTC
display
1st trip
DTC
display
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
QG16
I
18DE
Emission-related Diagnostic Information
EC-37