Wire Harness in Trunk
02-12-14, 04:11 PM
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Wire Harness in Trunk
While back from lexusownersclub posting I retrieved this with a solution. Now looking back the problem sounds like a caps in ECM but not sure. I am wondering if the wire harness in trunk is problem for any LS owner. Can anyone verify this to be a valid problem/solution?
Problem: Wire Harness in Trunk
I have a 92 LS400 with 159,000 miles. It just started doing this. The rpms will all of a sudden drop to almost 0, then the engine picks back up and it goes back to wherever; depending on where I have the gas pedal. Sometimes the car will die from having the pedal pressed.
This happens in gear or in park, while driving or when stopped. If I am in park and letting it idle, the rpms drop, and the car almost stalls, but then the rpms catch back up and it goes to the correct idle. I let it sit like this yesterday, and it just kept doing it over and over again.
I also tried pressing the gas pedal to bring the rpms up to almost 3,000, and it would do the same thing, then go back up to where I had it if my foot was still on the pedal. This same type of problem happened to me about a year ago. This smooth world class car started balking, cutting out, lurching, wild rpms, dash flickering, just seemed ready for the junk yard. It happened all of a sudden. No warning. I thought the engine was toast.
Now it's smooth as silk w/ 255,000 miles on it.
Solution:
Open the trunk. On the left side you will see a wire harness on the left hinge. After repeated openings and closings the wires inside that harness become fatigued and frayed. Then they start shorting out. Then sputtering, stalling, and everything you describe. This is a design flaw and lexus knows it. If this describes your problem, then remove the plastic bracket on the left hinge, strip down the harness, untwist all the wires, re-connect, then re-tape. Make sure to leave off the hinge bracket that ensures tension on the harness. Just let the whole mess swing free and loose. In my case, problem solved, and no spending thousands of dollars in diagnostics, parts, and tech snafus. Best of all, it's free. Takes about 30 minutes.
Problem: Wire Harness in Trunk
I have a 92 LS400 with 159,000 miles. It just started doing this. The rpms will all of a sudden drop to almost 0, then the engine picks back up and it goes back to wherever; depending on where I have the gas pedal. Sometimes the car will die from having the pedal pressed.
This happens in gear or in park, while driving or when stopped. If I am in park and letting it idle, the rpms drop, and the car almost stalls, but then the rpms catch back up and it goes to the correct idle. I let it sit like this yesterday, and it just kept doing it over and over again.
I also tried pressing the gas pedal to bring the rpms up to almost 3,000, and it would do the same thing, then go back up to where I had it if my foot was still on the pedal. This same type of problem happened to me about a year ago. This smooth world class car started balking, cutting out, lurching, wild rpms, dash flickering, just seemed ready for the junk yard. It happened all of a sudden. No warning. I thought the engine was toast.
Now it's smooth as silk w/ 255,000 miles on it.
Solution:
Open the trunk. On the left side you will see a wire harness on the left hinge. After repeated openings and closings the wires inside that harness become fatigued and frayed. Then they start shorting out. Then sputtering, stalling, and everything you describe. This is a design flaw and lexus knows it. If this describes your problem, then remove the plastic bracket on the left hinge, strip down the harness, untwist all the wires, re-connect, then re-tape. Make sure to leave off the hinge bracket that ensures tension on the harness. Just let the whole mess swing free and loose. In my case, problem solved, and no spending thousands of dollars in diagnostics, parts, and tech snafus. Best of all, it's free. Takes about 30 minutes.
02-12-14, 05:17 PM
#3
Lexus Champion
Michael, you should have searched the forum here before racking your brain, this must be one of the most discussed and most common LS400 issues in the history of Club Lexus!
It's even more common than failing ECU capacitors (and keep in mind that the harness cracking issue was resolved for the 95 and newer models!)
once you have verified the the integrity of the wires in the driver's trunk hinge area and repaired them as necessary, only then do you want to look at ECU capacitors as a suspect!
It's even more common than failing ECU capacitors (and keep in mind that the harness cracking issue was resolved for the 95 and newer models!)
once you have verified the the integrity of the wires in the driver's trunk hinge area and repaired them as necessary, only then do you want to look at ECU capacitors as a suspect!
02-12-14, 05:29 PM
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Wire Harness
That wire harness at the left hinge is not something you can visually check for disconnect. If there is a disconnect, you would have to take it apart to see it.
02-12-14, 05:37 PM
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Wire Harness
Michael, you should have searched the forum here before racking your brain, this must be one of the most discussed and most common LS400 issues in the history of Club Lexus!
It's even more common than failing ECU capacitors (and keep in mind that the harness cracking issue was resolved for the 95 and newer models!)
once you have verified the the integrity of the wires in the driver's trunk hinge area and repaired them as necessary, only then do you want to look at ECU capacitors as a suspect!
It's even more common than failing ECU capacitors (and keep in mind that the harness cracking issue was resolved for the 95 and newer models!)
once you have verified the the integrity of the wires in the driver's trunk hinge area and repaired them as necessary, only then do you want to look at ECU capacitors as a suspect!
02-12-14, 06:00 PM
#6
Lexus Champion
yes, I think it is in the FAQ and you do have to unwrap/unbundle the wires in the driver's trunk hinge area to find the broken one or two, but once the individual wires are exposed it should be obvious and easy to find the broken one(s) - if I recall, a white wire in there likes to break often
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