Pinpoint Test DX: Engine Coolant Temperature (ECT) Sensor: Introduction: Notes

NOTE: This pinpoint test is intended to diagnose the following:

Engine coolant temperature (ECT) sensor (12A648).
Harness circuits: ECT & SIGRTN.
Powertrain control module (PCM) (12A650).

Engine coolant temperature must be greater than 10°C (50°F) to pass the KOEO self-test and greater than 82°C (180°F) to pass the KOER self-test. To accomplish this, the engine must be at normal operating temperature .

Voltage values calculated for VREF = 5 volts. These values can vary by 15% due to sensor and VREF variations .

Fig 1: Engine Coolant Temperature (ECT) Sensor Temperature/Voltage Graph

Courtesy of FORD MOTOR CO.

TEMPERATURE SENSOR VOLTAGE AND RESISTANCE SPECIFICATIONS

Temperature		Temperature Sensor Values
°C	°F	voltage	Resistance (K ohms)
120	248	0.28	1.18
110	230	0.36	1.55
100	212	0.47	2.07
90	194	0.61	2.80
80	176	0.80	3.84
70	158	1.05	5.37
60	140	1.37	7.70
50	122	1.77	10.97
40	104	2.23	16.15
30	86	2.74	24.27
20	68	3.26	37.30
10	50	3.73	58.75
0	32	4.14	95.85
-10	14	4.45	160.31

Fig 2: Identifying Engine Coolant Temperature (ECT) Sensor Connector

Courtesy of FORD MOTOR CO.