Jeepers Creepers [E184]

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Thanks to our Partner, NAPA Autotech Training

Key Points & Takeaways:

The Problem:

  • A 2023 Jeep Grand Cherokee (collision repair) came in with blind spot warning and parking aid malfunction lights on.
  • No functionality in either system post-repair.

Initial Diagnosis:

  • Verified the concern (instrument cluster lit up with warnings).
  • Used an aftermarket scan tool (Snap-on Ultra) and found:
  • ADAS control module had multiple DTCs for open/short circuits on all radar sensors.
  • Parking aid module had similar codes for ultrasonic sensors.
  • Vehicle was hit in the passenger rear, leading to replacement of the bumper, harness, and rear hatch.

Suspected Causes:

  • Blown fuse (common culprit for multiple system failures).
  • Crushed/damaged wiring harness (common after collisions).
  • Module failure due to impact.

Testing & Findings:

  • Checked power and ground at the ADAS module—all good.
  • Inspected wiring harness for damage (no visible issues).
  • Critical Clue: Wire colors didn’t match the schematic.
  • Initially dismissed as a common schematic error.
  • Later realized the entire harness was installed backward (left/right sides flipped).

The Fix:

  • Flipped the harness and radar modules to their correct positions.
  • All codes cleared except two for the blind spot radars—turned out they were also swapped.
  • After correction, all systems worked perfectly.

Lessons Learned:

  • Don’t get stuck in a diagnostic rabbit hole. Good techs pivot when clues don’t add up.
  • Man-made problems can be the trickiest. Always verify previous work (especially after collisions).
  • Wire color discrepancies matter. Even if schematics are often wrong, they can reveal bigger issues.
  • “Slow down to speed up.” Rushing leads to wasted time; methodical checks save hours.

Final Thoughts:

  • Awareness is key. Catch yourself when fixating on one theory.
  • Experience can work against you. Stay open to new clues, even if they conflict with past patterns.

Contact Information

The Aftermarket Radio Network: https://aftermarketradionetwork.com/

Remarkable Results Radio Podcast with Carm Capriotto: Advancing the Aftermarket by Facilitating Wisdom Through Story Telling and Open Discussion. https://remarkableresults.biz/

Diagnosing the Aftermarket A to Z with Matt Fanslow: From Diagnostics to Metallica and Mental Health, Matt Fanslow is Lifting the Hood on Life. https://mattfanslow.captivate.fm/

Business by the Numbers with Hunt Demarest: Understand the Numbers of Your Business with CPA Hunt Demarest. https://huntdemarest.captivate.fm/

The Auto Repair Marketing Podcast with Kim and Brian Walker: Marketing Experts Brian & Kim Walker Work with Shop Owners to Take it to the Next Level. https://autorepairmarketing.captivate.fm/

The Weekly Blitz with Chris Cotton: Weekly Inspiration with Business Coach Chris Cotton from AutoFix – Auto Shop Coaching. https://chriscotton.captivate.fm/

Speak Up! Effective Communication with Craig O’Neill: Develop Interpersonal and Professional Communication Skills when Speaking to Audiences of Any Size. https://craigoneill.captivate.fm/

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