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:

harness circuits: B+, ISP-R, PCMRC and VPWR
PCM power relay (12A646)
PCM (12A650)

Fig 1: Powertrain Control Module Power (PCM Power) Relay Connector

Courtesy of FORD MOTOR CO.

Pin	Circuit
5	VPWR (Vehicle Power)
2	PCMRC (PCM Relay Control)
1, 3	B+ (Battery Positive Voltage)

Fig 2: Powertrain Control Module (PCM) Connector

Courtesy of FORD MOTOR CO.

Pin	Circuit
B11, B12	VPWR (Vehicle Power)
B1	PCMRC (PCM Relay Control)
B8	ISP-R (Ignition Switch Position Run)

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 B: Powertrain Control Module (Pcm) Power Relay: Introduction

Use the Manual With the Right Hardware

When to See a Mechanic

Rather have a pro handle this?