Diagnostic Method

• Abnormality Judgment 

Judge as NG when the malfunction criteria below are met.

Judgment Value 

Malfunction Criteria	Threshold Value
Engine coolant temperature	< 20°C (68°F)
Timer for diagnosis after engine starting	≥Judgment value of timer after engine starting

Timer for diagnosis after engine Starting

1. Timer stop at fuel cut mode.
2. During the driving conditions except a) above, timer count up by 64 milliseconds + TWCNT milliseconds at every 64 milliseconds.

TWCNT is defined as follows,

TWCNT = 0 at idle switch ON,

TWCNT show on the following table at idle switch OFF.

Temperature °C (°F)	Vehicle speed km/h (MPH)
	0(0)	8 (4.97)	16(9.94)	24(14.9)	32(19.9)	40 (24.9)	48 (29.8)	56 (34.8)
-20 (-4)	0 ms	37.1 ms	72.3 ms	111.4 ms	126.7 ms	141.9 ms	163.6 ms	185.3 ms
-10(14)	0 ms	27.4 ms	54.8 ms	82.2 ms	99.7 ms	117.1 ms	136.0 ms	154.8 ms
0(32)	0 ms	17.6 ms	35.3 ms	52.9 ms	72.6 ms	92.3 ms	108.3 ms	124.3 ms
10 (50)	0 ms	7.9 ms	15.8 ms	23.7 ms	45.6 ms	67.6 ms	80.7 ms	93.9 ms
20 (68)	0 ms	7.9 ms	15.8 ms	23.7 ms	45.6 ms	67.6 ms	80.7 ms	93.9 ms

Judgment value of timer after engine starting

t = 429.5 - 28.605 x Ti

Ti is the lowest coolant temperature after starting the engine.

Time Needed for Diagnosis:  To be determined. (It is varied by the Min. engine coolant temperature and engine conditions such as vehicle speed and engine coolant temperature.)

Malfunction Indicator Light Illumination:  Illuminates when malfunction occurs in 2 continuous driving cycles.

• Normality Judgment 

Judge as OK and clear the NG when the malfunction criteria below are met.

Judgment Value 

Malfunction Criteria	Threshold Value
Engine coolant temperature	≥ 20°C (68°F)