ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION — Introduction; Two Trip Detection Logic; Emission-related Diagnostic Information
EF & EC-7028prose procedureIntroduction
CG10, CGA3
The ECM has an on board diagnostic system which detects malfunctions related to engine sensors or actuators. The ECM also records various emission-related diagnostic information including:
Diagnostic information recorded by ECM
Diagnostic Trouble Code (DTC)
ModeMode 3 of ISO 15031-51/SAE J1979
Freeze Frame data
ModeMode 2 of ISO 15031-51/SAE J1979
System Readiness Test (SRT) code
ModeMode 1 of ISO 15031-51/SAE J1979
1st Trip Diagnostic Trouble Code (1st trip DTC)
ModeMode 7 of ISO 15031-51/SAE J1979
1st trip Freeze Frame data
Mode
Heated oxygen sensor test results
ModeMode 5 of ISO 15031-51/SAE J1979
Test values and Test limits
ModeMode 6 of ISO 15031-51/SAE J1979
The above information can be checked using procedures listed in the table below.
Information availability by tool
CONSULT-II*2
DTCX
1st trip DTCX
Freeze Frame dataX
1st trip Freeze Frame dataX
SRT codeX
Test value—
GST*2
DTCX
1st trip DTCX*1
Freeze Frame dataX
1st trip Freeze Frame data—
SRT codeX
Test valueX
NOTE
*1: 1st trip DTCs for self-diagnosis concerning SRT items cannot be shown on the GST display.
*2: M: SELF-DIAGNOSTIC RESULTS mode, DTC is displayed; DTC uses "P" and a set of four digit numbers.
The malfunction indicator (MI) on the instrument panel lights up when the same malfunction is detected in two consecutive trips (Two trip detection logic), or when the ECM enters fail-safe mode. (Refer to EC-7055.)
Two Trip Detection Logic
When a malfunction is detected for the first time, 1st trip DTC is stored and 1st trip Freeze Frame data is retained in the ECM memory. The MI will not light up at this stage <1st trip>.
If the same malfunction is detected again during the next drive, the DTC and Freeze Frame data are stored in the ECM memory, and the MI lights up. At the same time when the DTC is stored <2nd trip>. The "trip" in the "Two Trip Detection Logic" means a driving mode in which self-diagnosis is performed during vehicle operation. Specific on board diagnostic items will cause the ECM to light up or blink the MI, and store DTC and Freeze Frame data, even in the 1st trip, as shown below.
MI and DTC behavior by item
Misfire (Possible three way catalyst damage) — DTC: P0300 - P0304 is being detected
MI BlinkingX
MI Lighting up—
DTC 1st trip lighting up—
DTC 2nd trip displayingX
1st trip DTC 1st trip lighting upX
1st trip DTC 2nd trip displaying—
Misfire (Possible three way catalyst damage) — DTC: P0300 - P0304 has been detected
MI Blinking—
MI Lighting upX
DTC 1st trip lighting up—
DTC 2nd trip displayingX
1st trip DTC 1st trip lighting up—
1st trip DTC 2nd trip displaying—
ETC sensor and crankshaft position sensor (pos) (Refer to EC-7055.)
MI Blinking—
MI Lighting upX
DTC 1st trip lighting up—
DTC 2nd trip displayingX*
1st trip DTC 1st trip lighting up—
1st trip DTC 2nd trip displaying—
Except above
MI Blinking—
MI Lighting up—
DTC 1st trip lighting up—
DTC 2nd trip displayingX
1st trip DTC 1st trip lighting up—
1st trip DTC 2nd trip displayingX
Emission-related Diagnostic Information
DTC AND 1ST TRIP DTC
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
See also
EC-7055