Important Safety Notice

WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

Appropriate repair methods and procedures are essential for the safe, reliable operation of all motor vehicles, as well as the personal safety of the individual doing the work. This article provides general directions for repairing vehicles with tested, effective techniques. Following them will help ensure reliability. There are numerous variations in procedures, techniques, tools, and parts for repairing vehicles, as well as in the skill of the individual doing the work. This article cannot possibly anticipate all such variations and provide advice or cautions as to each. Accordingly, anyone who departs from the instructions provided in this article must first establish that they compromise neither their personal safety nor the vehicle integrity by their choice of methods, tools, or parts.

This pinpoint test is intended to diagnose the following:

Integrated mass air flow (MAF)/intake air temperature (IAT) sensor (12B579).
Harness circuits IAT, VREF, 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: Temperature And 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 Mass Air Flow/Intake Air Temperature (MAF/IAT) Sensor Connector

Courtesy of FORD MOTOR CO.

Fig 3: Identifying Powertrain Control Module (PCM) Connector

Courtesy of FORD MOTOR CO.