OBD System Operation Chart

Relationship Between MIL, DTC, 1st Trip DTC, and Detectable Items

When a malfunction is detected for the first time, the 1st trip DTC and the 1st trip freeze frame data are stored in the ECM memory.
When the same malfunction is detected in two consecutive trips, the DTC and the freeze frame data are stored in the ECM memory, and the MIL will illuminate.
The MIL will turn off after the vehicle is driven 3 times (driving pattern B) with no malfunction. A drive is counted only when the recorded driving pattern is met (as stored in the ECM). If another malfunction occurs while counting, the counter will reset.
The DTC and the freeze frame data will be stored until the vehicle is driven 40 times (driving pattern A) without the same malfunction recurring (except for Misfire and Fuel Injection System). For Misfire and Fuel Injection System, the DTC and freeze frame data will be stored until the vehicle is driven 80 times (driving pattern C) without the same malfunction recurring. The "TIME" in "SELF-DIAGNOSTIC RESULTS" mode of CONSULT-III will count the number of times the vehicle is driven.
The 1st trip DTC is not displayed when the self-diagnosis results in OK for the 2nd trip.

Summary Chart

SUMMARY CHART

Items	Fuel Injection System	Misfire	Other
MIL (turns off)	3 (pattern B)	3 (pattern B)	3 (pattern B)
DTC, Freeze Frame Data (no display)	80 (pattern C)	80 (pattern C)	40 (pattern A)
1st Trip DTC (clear)	1 (pattern C), *1	1 (pattern C), *1	1 (pattern B)
1st Trip Freeze Frame Data (clear)	1, 2	1, 2	1 (pattern B)

For details about patterns B and C under "Fuel Injection System" and "Misfire", see the following EXPLANATION FOR DRIVING PATTERNS FOR "MISFIRE <EXHAUST QUALITY DETERIORATION>", "FUEL INJECTION SYSTEM". .

For details about patterns A and B under Other, see the following EXPLANATION FOR DRIVING PATTERNS FOR "MISFIRE <EXHAUST QUALITY DETERIORATION>", "FUEL INJECTION SYSTEM". .

*1: Clear timing is at the moment OK is detected.

*2: Clear timing is when the same malfunction is detected in the 2nd trip.

Relationship Between MIL, DTC, 1st Trip DTC and Driving Patterns for "Misfire <EXHAUST QUALITY Deterioration>", "Fuel Injection System"

Fig 1: Relationship Between MIL, DTC, 1st Trip DTC And Driving Patterns For Misfire - Exhaust Quality Deterioration And Fuel Injection System

Courtesy of NISSAN MOTOR CO., U.S.A.

Explanation for Driving Patterns for "Misfire <EXHAUST QUALITY Deterioration>", "Fuel Injection System"

Driving pattern B means the vehicle operation as per the following:

All components and systems should be monitored at least once by the OBD system.

The B counter will be cleared when the malfunction is detected once regardless of the driving pattern.
The B counter will be counted up when driving pattern B is satisfied without any malfunction.
The MIL will turn off when the B counter reaches 3. (*2 in "OBD SYSTEM OPERATION CHART")

Driving pattern C means operating vehicle as per the following:

The following conditions should be satisfied at the same time:

Engine speed: (Engine speed in the freeze frame data) ± 375 RPM

Calculated load value: (Calculated load value in the freeze frame data) x (1 ± 0.1) [%]

Engine coolant temperature (T) condition:

When the freeze frame data shows lower than 70°C (158°F), T should be lower than 70°C (158°F).
When the freeze frame data shows higher than or equal to 70°C (158°F), T should be higher than or equal to 70°C (158°F).

Example:

If the stored freeze frame data is as per the following:

Engine speed: 850 RPM, Calculated load value: 30%, Engine coolant temperature: 80°C (176°F)

To be satisfied with driving pattern C, the vehicle should run under the following conditions:

Engine speed: 475 - 1, 225 RPM, Calculated load value: 27 - 33%, Engine coolant temperature: more than 70°C (158°F)

The C counter will be cleared when the malfunction is detected regardless of vehicle conditions above.
The C counter will be counted up when vehicle conditions above are satisfied without the same malfunction.
The DTC will not be displayed after C counter reaches 80.
The 1st trip DTC will be cleared when C counter is counted once without the same malfunction after DTC is stored in ECM.

Relationship Between MIL, DTC, 1st Trip DTC and Driving Patterns Except For "Misfire <EXHAUST QUALITY Deterioration>", "Fuel Injection System"

Fig 2: Relationship Between MIL, DTC, 1st Trip DTC And Driving Patterns For Misfire Exhaust Quality Deterioration And Fuel Injection System

Courtesy of NISSAN MOTOR CO., U.S.A.

Explanation for Driving Patterns Except for "Misfire <EXHAUST QUALITY Deterioration>", "Fuel Injection System"

Fig 3: Driving Patterns For Misfire - Exhaust Quality Deterioration And Fuel Injection System

Courtesy of NISSAN MOTOR CO., U.S.A.

The A counter will be cleared when the malfunction is detected regardless of (1) - (4).
The A counter will be counted up when (1) - (4) are satisfied without the same malfunction.
The DTC will not be displayed after the A counter reaches 40.

Driving pattern B means operating vehicle as per the following:

All components and systems should be monitored at least once by the OBD system.

The B counter will be cleared when the malfunction is detected once regardless of the driving pattern.
The B counter will be counted up when driving pattern B is satisfied without any malfunctions.
The MIL will turn off when the B counter reaches 3 (*2 in OBD SYSTEM OPERATION CHART).