Uploaded August 2026 | Updated September 2026, 3 weeks ago

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In this quick diagnostic video, we troubleshoot a 2020 Jeep Cherokee 2.4L 4WD with a U11E9 – Lost Communication With Active Grille Shutter (AGS) fault code. We walk through the active grille shutter circuit, check the LIN bus communication signal, and uncover a corroded power wire causing a major voltage drop under load. This is a great example of why seeing battery voltage on an unloaded circuit doesn’t mean the circuit can actually carry current. Using a scope, wiring diagrams, voltage testing, and bidirectional controls, we confirm the repair and get the active grille shutters working again. If you're learning automotive electrical diagnostics, voltage drop testing, LIN bus diagnostics, or navigating network communication faults, this is a quick real-world case study you’ll want to see.

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0:00 Active grill shutter fault and initial scan data
1:30 Wiring diagram and LIN bus circuit overview
2:47 Visual inspection reveals wiring corrosion
3:22 Testing the power feed — only 2.6 volts under load
3:44 Checking the LIN bus signal with a scope
4:44 Shared LIN bus communication explained
5:23 Voltage drop lesson — 12 volts unplugged, 3 volts plugged in
6:24 Repairing the damaged power feed wire
7:22 Verifying proper voltage after the repair
7:59 Rechecking the LIN bus signal
9:26 Attempting to verify communication and clear the fault
10:46 Scan tool secure gateway causes unexpected problems
12:54 Logging back into AutoAuth restores scan tool functions
14:29 Active grill shutter operation confirmed
14:50 Bidirectional open/close test
15:53 Key takeaways: LIN bus, loaded-circuit testing, and secure gateway

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ScannerDanner LLC is not responsible for misuse, unauthorized changes, or incorrect application of any information provided. Always follow proper safety protocols when using tools, equipment, or procedures discussed in this video. Use this content at your own risk.