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

WARNING: THIS VEHICLE IS EQUIPPED WITH HIGH VOLTAGE CABLES, COMPONENTS, AND WIRING. THE HIGH VOLTAGE WARNING LABELS CONTAINING THE HIGH VOLTAGE SYMBOL ARE LOCATED ON EACH HIGH VOLTAGE COMPONENT. HIGH VOLTAGE CABLES AND WIRING ARE ORANGE IN COLOR. CERTIFIED RUBBER INSULATING GLOVES AND A FACE SHIELD MUST BE WORN WHEN WORKING WITH THE HIGH VOLTAGE CABLES, COMPONENTS, OR WIRING. THE IGNITION KEY MUST BE CYCLED TO THE OFF POSITION FOR A MINIMUM OF 5 MINUTES, AND THE HIGH VOLTAGE TRACTION BATTERY SERVICE DISCONNECT PLUG PLACED IN THE SERVICING/SHIPPING POSITION BEFORE DISCONNECTING THE HIGH VOLTAGE CABLES. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY OR DEATH.
DO NOT DISCONNECT, DISABLE, OR TOUCH THE HIGH VOLTAGE CABLES, COMPONENTS, OR WIRING DURING THE MODULE REPROGRAMMING PROCEDURE BECAUSE HIGH VOLTAGE IS PRESENT. THE HIGH VOLTAGE WARNING LABELS CONTAINING THE HIGH VOLTAGE SYMBOL ARE LOCATED ON EACH HIGH VOLTAGE COMPONENT. HIGH VOLTAGE CABLES AND WIRING ARE ORANGE IN COLOR. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY OR DEATH.

This pinpoint test is intended to diagnose the following:

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

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

Fig 1: Temperature Sensor Voltage And 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.

MASS AIR FLOW/INTAKE AIR TEMPERATURE (MAF/IAT) SENSOR CONNECTOR PIN REFERENCE CHART

Pin	Circuit
2	SIGRTN (Signal Return)
1	IAT (Intake Air Temperature)

Fig 3: Powertrain Control Module (PCM) Connector

Courtesy of FORD MOTOR CO.

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR PIN REFERENCE CHART

Pin	Circuit
B41	MAF RTN (Mass Air Flow Return)
B58	SIGRTN (Signal Return)
B47	IAT (Intake Air Temperature)