DTC P1A03: Generator Motor Shutdown Circuit

2010 Mercury Mariner Hybrid, AWDSECTION DTC P1A03: Generator Motor Shutdown Circuit
WARNING: This page is about a different car, the 2011 Mercury Milan, 2011 Lincoln MKZ, 2011 Ford Fusion, 2010 Mercury Milan, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
P1A03 - GENERATOR MOTOR SHUTDOWN CIRCUIT

Description:  The transaxle control module (TCM) continuously monitors the generator motor shutdown (GMSDN) circuit and the controller area network (CAN) signal for a GMSDN request from the powertrain control module (PCM). This DTC sets when the PCM requests generator or traction motor shutdown through the CAN signal or if there is an GMSDN circuit concern. The generator and traction motor inverters will be disabled.
Possible Causes: 
  • GMSDN circuit open
  • GMSDN circuit short to PWR or GND
  • PCM GMSDN request
  • Damaged PCM
  • Damaged TCM
Diagnostic Aids:  With the PCM and TCM connected and the ignition in ON position, check the GMSDN signal frequency. If the frequency is between 49 and 75 Hz DC, no circuit problem is indicated and PCM traction motor shutdown is requested.
Application  Key On Engine Off  Key On Engine Running  Continuous Memory 
All GO to PINPOINT TEST TE .
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.