Pinpoint Test AJ: Powertrain Control Module (Pcm) Power Relay

2021 Ford Transit-350 HD Base, Van Cargo Extended, 3.5L Eng VIN 8, AWDSECTION Pinpoint Test AJ: Powertrain Control Module (Pcm) Power Relay
WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Regeneration may occur during normal operation. During regeneration, diagnostic procedures may display biased values. If a regeneration occurs during diagnostic procedures, allow the process to complete before continuing diagnostics.

Normal Operation and Fault Conditions 

Refer to the DTC Fault Trigger Conditions.

DTC Fault Trigger Conditions 

DTC Description Fault Trigger Condition
PCM P0685:00 ECM/PCM Power Relay Control Circuit/Open: No Sub Type Information Sets when the PCM detects the ignition switch position run (ISP-R) circuit indicates the ignition is in the off or accessory mode, and the amount of time the PCM remains powered through the PCM power relay exceeds a predetermined amount of time.
PCM P068A:00 ECM/PCM Power Relay De-Energized - Too Early: No Sub Type Information Sets when the PCM detects the PCM power relay is de-energized too early.
PCM P068B:00 ECM/PCM Power Relay De-Energized - Too Late: No Sub Type Information Sets when the PCM detects the PCM power relay takes longer than a specified time threshold to de-energize after it was commanded off.
PCM P2507:00 ECM / PCM Power Input Signal Low: No Sub Type Information Sets when the PCM detects the PCM 5 volt power supply voltage is less than a calibrated threshold.
PCM P2508:00 ECM / PCM Power Input Signal High: No Sub Type Information Sets when the PCM detects the PCM internal 5 volt power supply voltage is greater than a calibrated threshold.

Possible Sources 

  • Charging system concern
  • PCM power relay control circuitry concern
  • PCM power relay (12A646)
  • PCM (12A650)

PINPOINT TESTS AJ: POWERTRAIN CONTROL MODULE (PCM) POWER RELAY (Diesel)

RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

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.