DTC P0606: Powertrain Control Module (PCM) Internal Communication Error

2005 Ford GTSECTION DTC P0606: Powertrain Control Module (PCM) Internal Communication Error
WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2005 Mercury Sable, 2005 Mercury Mountaineer, 2005 Mercury Monterey, 2005 Mercury Montego, and 2005 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.
P0606 - POWERTRAIN CONTROL MODULE (PCM) INTERNAL COMMUNICATION ERROR

Description:  P0606 indicates a register readback (PCM internal communications) error.
Possible Causes: 
  • Damaged PCM
Diagnostic Aids:  Internal PCM failure. Install a new PCM.
For Electronic Throttle Control applications, an internal PCM failure, or an ETC system FMEM condition exists. Repairing the other DTCs can fix the P0606.
Application  Key On Engine Off  Key On Engine Running  Continuous Memory 
Vehicles With Electronic Throttle Control (ETC) The DTC is an indication of a failure mode in the electronic throttle control system, which includes the accelerator pedal position (APP) sensor, electronic throttle body (ETB), and powertrain control module (PCM). It is accompanied by other DTCs which provide repair direction. Diagnose and repair those DTCs, and the P0606 will not be reset.
All others Make sure to check for aftermarket performance products before installing a new powertrain control module (PCM). If it is necessary to install a new PCM, refer to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) .
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.