What does the P0725 code indicate on Jeep vehicles?

So I have a 1999 Jeep Grand Cherokee Limited with a 4.7 V8 engine. I keep having a problem where, once the engine reaches its normal temperature (210°F), it randomly stalls. There’s no warning or sputtering; it just dies. Sometimes I can restart it right away, but often I have to wait 5 to 30 minutes before it will start again.

When it won’t start, the voltage gauge barely moves when I turn the key to the “on” position. Sometimes it throws a P0725 code, and once it threw a P0700 code.

So far, I’ve replaced:

  1. Crankshaft position sensor
  2. Crankshaft position sensor wiring and plug
  3. Battery terminals
  4. Input and output sensors on the transmission
  5. Transmission control module (which fixed the 5th gear issue)

I also just got a used, rebuilt Mopar PCM from 2015 from the junkyard. I haven’t tried it yet because I need to have the VIN and mileage flashed, and the dealer is closed on Sundays. Plus, it costs an extra $100 to get it flashed, and I’m not sure if that’s the real issue.

Can anyone offer some advice or suggest something else to check before I replace the PCM?

The P0725 code on Jeep vehicles indicates an issue with the Engine Speed Input Circuit. This problem is typically linked to the crankshaft position sensor or its wiring, which may be malfunctioning or damaged.

Given the stalling of your Jeep Grand Cherokee when it reaches operating temperature, along with intermittent starting issues and specific error codes, the problem likely involves a complex electrical or engine management issue.

Potential Causes:

Fuel System:

  • Fuel Pump: A failing fuel pump may not provide adequate pressure when the engine is hot.
  • Fuel Filter: A clogged fuel filter can restrict fuel flow to the engine.
  • Injectors: Faulty injectors could lead to misfires and stalling.

Electrical System:

  • Ground Connections: Corroded or loose ground connections can disrupt electrical signals.
  • Wiring Harness: Inspect for damaged or frayed wires, especially in the engine compartment.
  • Alternator: A failing alternator might impact the electrical system and cause stalling.

Cooling System:

  • Overheating Issues: Although the engine reaches normal temperature, any overheating issues can affect performance.

Next Steps:

  1. Check Fuel Pressure: Use a fuel pressure gauge to ensure proper fuel system performance.
  2. Inspect Fuel Injectors: Clean or replace the fuel injectors if needed.
  3. Verify Ground Connections: Ensure all ground connections are clean and securely attached.
  4. Test the Alternator: Check the alternator’s output to confirm it’s charging the battery correctly.
  5. Inspect the Cooling System: Make sure the cooling system is functioning correctly and no signs of overheating are present.

Additional Tips:

  • OBD-II Scanner: Use a code reader to check for any new error codes that may offer further clues.
  • Data Logging: Consider using a data logger to monitor engine parameters in real-time and detect trends.
  • Mechanic Consultation: If the issue persists, consulting a mechanic experienced with Jeep vehicles might be beneficial.

Before replacing the PCM, it’s important to explore these other possibilities as the PCM is costly and replacing it may not guarantee a fix.