Pinpoint Test DA: Intake Air Temperature (IAT) Sensor: Introduction

WARNING: This page does not describe the selected car, but rather 31 other vehicles, including the 2009 Mercury Mountaineer, 2009 Mercury Milan, 2009 Mercury Mariner, 2009 Mercury Grand Marquis, and 2009 Lincoln Town Car. 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: Temperature Sensor Voltage & Resistance Characteristic 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: Mass Air Flow/Intake Air Temperature (MAF/IAT) Sensor Connector

Courtesy of FORD MOTOR CO.

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

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR

Vehicle	Connector	Pin	Circuit
E-Series 4.6L, E-Series 5.4L, Expedition, F-150, Focus, Navigator	190-Pin	B58 B47	SIGRTN IAT
Edge, Flex, MKS, MKX, Sable, Taurus, Taurus X	190-Pin	B58 B43	SIGRTN IAT
Escape/Mariner	190-Pin	B56 B47	SIGRTN IAT
Fusion, Milan, MKZ	140 Pin	B58 B43	SIGRTN IAT
Town Car	170 Pin	T41 E22	SIGRTN IAT
All other vehicles	170 Pin	E58 E22	SIGRTN IAT