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2020 Dodge Charger Hellcat - No Start, U0100 Code

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David L. · rep 0 · May 25, 4:14 AM · 1 replies · solved · Question

Vehicle: 2020 Dodge Charger Hellcat

My 2020 Dodge Charger Hellcat is completely dead. I went to start it this morning, and nothing. No crank, no lights on the dash, just silence. I checked the battery, and it seems fine, fully charged. When I hooked up my scanner, it's showing a U0100 code: Lost Communication With ECM/PCM 'A'.

This is really concerning for a relatively new car. I tried disconnecting the battery for a bit, but that didn't help. Could this be a fuse? Or something more serious like a bad computer? Any ideas on where to start troubleshooting this kind of issue on a modern Dodge? I'm stranded and need some guidance.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 4:14 AM

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ClearTheCode admin answer: A U0100 code, indicating lost communication with the Engine Control Module/Powertrain Control Module (ECM/PCM), is a critical diagnostic trouble code that can lead to a no-start condition. Here's a systematic approach to troubleshooting:

  1. Check Battery Voltage & Connections: Even if the battery seems charged, ensure it has sufficient cranking amps. A weak battery can cause communication issues. Also, verify that the battery terminals are clean and securely connected, as loose connections can disrupt power to critical modules.
  2. Inspect Fuses: The ECM/PCM relies on constant power. Check all fuses related to the PCM, ignition, and main power distribution in both the under-hood fuse box and any interior fuse panels. A blown fuse can cut power to the module, leading to a communication loss. Refer to your owner's manual for specific fuse locations.
  3. CAN Bus System: The U0100 code often points to an issue with the Controller Area Network (CAN) bus, which is how vehicle modules communicate. Look for signs of damage to the wiring harness leading to the PCM or other major modules. Corrosion, rodent damage, or pinched wires can disrupt the CAN bus.
  4. PCM Power & Ground: The PCM needs proper power and ground connections to function. Visually inspect the PCM's wiring harness connector for any corrosion, bent pins, or loose connections. A faulty ground strap could also be a culprit.
  5. Module Failure: In rarer cases, the PCM itself can fail, leading to a communication breakdown. This is usually a last resort diagnosis after ruling out power, ground, and wiring issues.

When to See a Shop:

  • If you've checked all fuses and battery connections and the code persists.
  • If you're uncomfortable testing electrical circuits or inspecting complex wiring harnesses.
  • If you suspect a PCM failure, as replacement often requires programming specific to your vehicle, which typically requires specialized dealer tools.
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