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2017 Jeep Cherokee KL - Transmission Shifting Issues & U0401 Code

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Chris P. · rep 0 · May 22, 3:21 AM · 1 replies · solved · Question

Vehicle: 2017 Jeep Cherokee Latitude

I'm having some really frustrating transmission issues with my 2017 Jeep Cherokee Latitude (2.4L engine). It's been shifting erratically, sometimes holding gears too long, and occasionally clunking into gear. The 'Service Transmission' message has popped up a few times.

I scanned it and got a U0401 code: 'Invalid Data Received From ECM/PCM A'. I know this is a communication code, but it seems to be tied to the transmission problems.

Has anyone else experienced this with their KL Cherokee? What could be causing this communication error and the transmission weirdness?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 3:21 AM

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ClearTheCode admin answer:

The U0401 code on your 2017 Jeep Cherokee Latitude, 'Invalid Data Received From ECM/PCM A', is a communication fault. This often indicates that the Transmission Control Module (TCM) or another module is not receiving proper data from the Engine Control Module (ECM) or Powertrain Control Module (PCM). This communication breakdown can absolutely lead to the erratic shifting and 'Service Transmission' messages you're experiencing.

Here are potential causes and diagnostic steps:

  1. Wiring Harness/Connectors: The most common cause for communication codes. Inspect the wiring harnesses and connectors between the ECM/PCM and the TCM for any signs of corrosion, damage, or loose connections. Pay close attention to the main harness going to the transmission and the ECM/PCM itself.
  2. Ground Issues: Poor ground connections can wreak havoc on vehicle electronics. Check the main ground straps from the battery to the chassis and engine, as well as any ground points for the ECM/PCM and TCM.
  3. Module Software/Firmware: Sometimes, outdated or corrupted software in the ECM/PCM or TCM can cause communication issues. A dealer might have a software update available that addresses known communication glitches.
  4. Faulty Module (ECM/PCM or TCM): While less common, one of the control modules could be internally faulty, preventing it from sending or receiving data correctly. This is usually a last resort diagnosis after ruling out wiring and power issues.
  5. CAN Bus Issues: The U0401 code points to a problem on the Controller Area Network (CAN) bus, which is the vehicle's communication network. A short or open circuit on the CAN bus lines can disrupt communication between multiple modules.

When to see a shop:

Given the complexity of diagnosing CAN bus issues and potential internal module faults, it is highly recommended to take your Jeep Cherokee to a dealership or a specialized transmission shop. They have advanced diagnostic tools (like WiTECH) that can monitor CAN bus activity, perform module diagnostics, and check for software updates. Attempting to diagnose this without proper equipment can be challenging and may lead to incorrect repairs.

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