WARNING: To prevent the risk of high-voltage shock, always follow precisely all warnings and service instructions, including instructions to depower the system. The high-voltage system utilizes approximately 300 volts DC, provided through high-voltage cables to its components and modules. The high-voltage cables and wiring are identified by orange harness tape or orange wire covering. All high-voltage components are marked with high-voltage warning labels with a high-voltage symbol. Failure to follow these instructions may result in serious personal injury or death.

This pinpoint test is intended to diagnose the following:

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

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

Courtesy of FORD MOTOR CO.

Fig 1: Mass Airflow/Intake Air Temperature (MAF/IAT) Sensor Connector

Courtesy of FORD MOTOR CO.

Harness Side

Circuit	Pin
VPWR (Vehicle Power)	3
IAT (Intake Air Temperature)	2
SIGRTN (Signal Return)	4

Fig 2: Powertrain Control Module (PCM) Connector

Courtesy of FORD MOTOR CO.

Harness Side

Circuit	Pin
IAT (Intake Air Temperature)	E17
SIGRTN (Signal Return)	E6

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

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

Use the Manual With the Right Hardware

When to See a Mechanic

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