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2018 Ram 1500 'Key Fob Not Detected' Intermittent Issue

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David L. · rep 0 · May 22, 3:34 AM · 1 replies · solved · Question

Vehicle: 2018 Ram 1500 Laramie

Hey everyone,

I'm having a really annoying problem with my 2018 Ram 1500 Laramie. About once a week, when I try to start it, I get the 'Key Fob Not Detected' message on the dash. Sometimes it happens when I try to unlock the doors too. I have to hold the fob right up to the start button or even use the emergency start procedure (holding the fob against the button) to get it to work.

I've replaced the battery in both of my key fobs, and the problem still pops up. It's completely random, and then it'll work fine for days. It's a push-button start system.

Could this be an issue with the Wireless Ignition Node (WIN) module, an antenna, or something else? Has anyone else experienced this with their 2018 Ram? It's getting frustrating to deal with.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 3:34 AM

0

ClearTheCode admin answer:

The 'Key Fob Not Detected' message on your 2018 Ram 1500 is a common complaint and points to an issue with the Passive Entry/Keyless Go system. Since you've already replaced the key fob batteries, we can look at other potential causes.

Common Causes for 'Key Fob Not Detected':

  • Weak Key Fob Signal: Even with new batteries, a faulty fob or interference can cause issues.
  • Wireless Ignition Node (WIN) Module Failure: The WIN module (also known as the RF Hub) is responsible for communicating with the key fob. A fault here is a primary suspect.
  • Antenna Issues: The vehicle has multiple antennas (often in the console, rear, and door handles) that pick up the key fob's signal. A faulty antenna or its wiring can cause intermittent detection.
  • Electrical Interference: External electronic devices or even internal vehicle electronics can sometimes interfere with the fob's signal.
  • Low Vehicle Battery Voltage: While less common for this specific message, low vehicle battery voltage can sometimes cause modules to behave erratically.

Troubleshooting Steps:

  1. Test Both Key Fobs: Ensure both of your key fobs exhibit the same behavior. If only one does, that fob might be faulty.
  2. Check for Interference: Try to start the vehicle in different locations to rule out external radio frequency interference. Also, remove any other electronic devices (phones, smartwatches, etc.) from near the start button.
  3. Perform a Hard Reset: Disconnect the negative battery terminal for 15-30 minutes. This can sometimes reset the WIN module and other related systems, clearing temporary glitches.
  4. Scan for Diagnostic Trouble Codes (DTCs): Use an OBD-II scanner. Look for 'B' (Body) or 'U' (Network) codes related to the keyless entry or ignition system. Relevant codes might include:
    • B1A08: Key Not Programmed (even if it was, a communication issue can trigger this).
    • B1A09: Key Fob Battery Low (even with new batteries, if the system isn't reading it correctly).
    • B1A25: WIN Module Internal Fault.
    • U0140: Lost Communication with Body Control Module (RF Hub is part of the BCM network).

When to See a Shop:

  • If the issue persists after trying both fobs, checking for interference, and performing a hard reset.
  • If you consistently get specific DTCs related to the WIN module or key fob communication.
  • If the problem becomes more frequent or makes starting the vehicle unreliable.
  • A dealership or a specialized automotive electrical shop has the necessary diagnostic tools (like WiTECH) to properly diagnose the WIN module, check antenna functionality, and reprogram key fobs if needed. This is often a complex issue requiring professional attention.
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