PINPOINT TEST DX: Engine Coolant Temperature (ECT) Sensor: Introduction

WARNING: This page does not describe the selected car, but rather 22 other vehicles, including the 2011 Mercury Milan, 2011 Mercury Mariner, 2011 Mercury Grand Marquis, 2011 Lincoln Town Car, and 2011 Lincoln Navigator L. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: 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.

This pinpoint test is intended to diagnose the following:

ECT sensor (12A648)
harness circuits: ECT and SIGRTN
powertrain control module (PCM) (12A650)

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 And Volatge 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.

Powertrain Control Module (PCM) Connector

For PCM connector views or reference values, refer to REFERENCE VALUES .

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR PINS REFERENCE CHART

Vehicle	Connector	Pin	Circuit
Mustang	190-PIN	E20 B56, E32, T38 E31	VREF SIGRTN ECT
Ranger	170 PIN	E57 B41, E58, T41 E18	VREF SIGRTN ECT
All other vehicles	128 PIN	B16, T11, T13 E3 E15	VREF SIGRTN ECT