How Bad Repairs and Rodent Damage Destroyed a Toyota Sienna's Engine Harness and Computer

Rodent Damage and Bad Repairs

• 💡 A 2011 Toyota Sienna required a new engine harness and computer due to severe rodent damage and subsequent improper repairs.
• ⚠️ The rodent damage initially caused wires to touch, frying the injector drivers, and further issues led to fried wires within the harness.
• 🎯 The customer opted for a full harness replacement to avoid ongoing back-and-forth repairs, prioritizing a definitive fix.

Engine Harness Replacement Process

• 🛠️ The primary challenge in replacing the engine harness was a crank sensor wire routed behind the AC compressor, necessitating its partial removal.
• 🔑 A golden rule emphasized is to never cut the old harness; remove it in one piece to ensure the new one can be installed correctly.
• 🧩 The process involved removing components like the cowl, air filter housing, and eventually the AC compressor to access and disconnect the harness.

Challenges and Detours

• ⚠️ Several missing brackets and damaged components, including a cracked drive belt and a deteriorating oil cooler line, were discovered during the repair.
• 🔧 The repair involved intricate work to disconnect the crank sensor connector, requiring careful maneuvering and sometimes accessing from the bottom of the vehicle.
• 🔌 Many connectors on the old harness were found to be broken or brittle, highlighting the extent of the damage and the necessity of replacement.

Reassembly and Programming

• ✅ After replacing the harness and computer, the process involved reassembling components in reverse order of removal.
• 💻 A new engine computer from Toyota required VIN programming before the vehicle could run without a check engine light.
• 🚀 The vehicle was successfully started and ran on all six cylinders, with no current warning lights or pending codes after VIN programming.

Final Touches and Recommendations

• ⚠️ The video highlights the importance of proper repair procedures, as missing brackets and damaged parts can lead to future issues.
• 💡 The owner was advised to implement rodent deterrents to prevent future damage.
• 🚗 The car was returned to the owner with the immediate critical repairs completed, with follow-ups for other identified issues like the oil cooler line.