DTC P0125 INSUFFICIENT COOLANT TEMPERATURE FOR CLOSED LOOP FUEL CONTROL

DTC P0125 INSUFFICIENT COOLANT TEMPERATURE FOR CLOSED LOOP FUEL CONTROL

(1)	Connector	(A)	Resistance value (kΩ)
(2)	Thermistor element	(B)	Temperature °C (°F)

ENABLE CONDITION

Secondary Parameters	Enable Conditions
Diagnosis of engine coolant temperature sensor property	Not finished
Engine speed	≥ 500 rpm
Battery voltage	> 10.9 V

GENERAL DRIVING CYCLE

Perform the diagnosis only once after engine starting.

DIAGNOSTIC METHOD

Abnormality Judgment

Judge NG when the malfunction criteria below are completed.

Judgment Value

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

Timer for diagnosis after engine starting

a.	Timer stop at fuel cut mode.

b.	During the driving conditions except a) above, timer count up by

65.5 milliseconds + TWCNT milliseconds at every 65.5 milliseconds.

Where, TWCNT is determined as follows,

TWCNT = 0 at idle switch ON,

TWCNT show on the following table at idle switch OFF.

Temp. °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	1.67 ms	3.33 ms	5.00 ms	13.11 ms	10.00 ms	19.66 ms	26.21 ms
−10 (14)	0 ms	13.11 ms	19.66 ms	32.77 ms	52.43 ms	72.09 ms	58.98 ms	45.88 ms
0 (32)	0 ms	18.24 ms	45.88 ms	72.09 ms	111.41 ms	150.73 ms	131.07 ms	104.86 ms
10 (50)	0 ms	39.32 ms	85.2 ms	124.52 ms	190.05 ms	229.38 ms	229.38 ms	183.50 ms

Judgment value of timer after engine starting

t = 429.5 − 6.685 × 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 OK and clear the NG when the malfunction criteria below are completed.

Judgment Value

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

DTC CLEAR CONDITION

•	When the OK idling cycle was completed 40 times in a row

•	When “Clear Memory” was performed

MALFUNCTION INDICATOR LIGHT CLEAR CONDITION

•	When the OK driving cycle was completed 3 times in a row

•	When “Clear Memory” was performed

FAIL SAFE

•	Engine coolant temperature process: Fix the engine coolant temperature at 70°C (158°F).

•	ISC feedback: Calculate the target engine speed setting the engine coolant temperature to 70°C (158°F).

•	ISC learning: Not allowed to learn.

•	Heavy fuel judgment control: Not allowed to carry out the heavy judgment.

•	Air conditioner control: Not allowed to turn the air conditioner to ON.

•	Radiator fan control: Both main and sub fan are in High driving.

ECM OPERATING AT DTC SETTING

Memorize the freeze frame data. (For test mode $02)