PINPOINT TEST DA: Intake Air Temperature (IAT) Sensor: Introduction

WARNING: This page does not describe the selected car, but rather 35 other vehicles, including the 2007 Mercury Mountaineer, 2007 Mercury Monterey, 2007 Mercury Montego, 2007 Mercury Milan, and 2007 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.

This pinpoint test is intended to diagnose the following:

integrated mass air flow/intake air temperature (MAF/IAT) sensor (12B579)
harness circuits: IAT and SIGRTN
powertrain control module (PCM) (12A650)

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

Fig 1: Intake Air Temperature (IAT) Sensor Temperature To Voltage Graph

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: Mass Air Flow/Intake Air Temperature (MAF/IAT) Sensor Connector - A

Courtesy of FORD MOTOR CO.

Fig 3: Mass Air Flow/Intake Air Temperature (MAF/IAT) Sensor Connector - B

Courtesy of FORD MOTOR CO.

Vehicle	Connector	Pin	Circuit
Escape 3.0L, Mariner 3.0L	A	4 1 6	MAF RTN SIGRTN IAT
All other vehicles	B	4 2 1	MAF RTN SIGRTN IAT

Powertrain Control Module (PCM) Connector

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

Vehicle	Connector	Pin	Circuit
Crown Victoria, Grand Marquis, Town Car	170 Pin	T41 E22	SIGRTN IAT
Edge, F-150, Mark LT, MKX	190 Pin	E58 E22	SIGRTN IAT
Escape, Focus, Mariner	150 (50-50-50) Pin	B41 B20	SIGRTN IAT
Expedition, Fusion, Milan, MKZ, Navigator	140 Pin	B58 B43	SIGRTN IAT
Five Hundred, Freestyle, Montego	150 (50-50-50) Pin	B41 E16	SIGRTN IAT
Freestar/Monterey, Taurus	104 Pin	91 39	SIGRTN IAT
All other vehicles	170 Pin	E58 E22	SIGRTN IAT