Nifty info on "Throttle-Shock Condition" in the 1995 LS 400
11-27-10, 06:07 PM
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Nifty info on "Throttle-Shock Condition" in the 1995 LS 400
Link: http://articles.orlandosentinel.com/...rque-converter
April 06, 1995|By Automotive NewsLOS ANGELES — Lexus is quietly fixing some of its all-new LS 400 cars because they jerk when decelerating.
Lexus is replacing the entire engine management computer for owners who report a problem. The fix takes about 30 minutes and is covered under warranty.
The cost to Lexus is ''several hundred dollars'' per vehicle, said Gordon Rush, national service operations manager.
The ''throttle-shock condition'' could affect about 8,000 LS 400s built before February. Since then, a revised engine control unit has been installed on the assembly line in Tahara, Japan.
Lexus spokesman Mike Michels said the condition is not a defect and that most LS 400 owners ''don't experience it or find it objectionable.
''There's no adverse effect on reliability or safety. There are no durability implications whatsoever,'' Michels said.
He estimated that a couple thousand owners would notice the condition.
Michels said Lexus' fix goes beyond the seriousness of the problem. He compared it to Lexus' recall of the first LS 400 cars in 1989 after one car had a cruise control button malfunction.
The problem occurs when drivers quickly remove their foot from the gas pedal between 45 and 60 mph. The engine's electronic control unit is supposed to put the vehicle into a ''glide'' mode with slight engine braking, but instead there is a slight bump or jolt.
Initially, the control unit was programmed to take several driving and shifting patterns into consideration. Under aggressive driving, fuel flow would shut off immediately if drivers quickly took their foot off the gas, then the transmission's torque converter would unlock.
That caused the jerky deceleration, because the engine revolutions would slow to zero and force a drag on the transmission. The new control unit first unlocks the torque converter, then shuts off the fuel flow.
Michels said the 1995 LS 400's control unit initially was revised to help the car meet stricter emissions and fuel-economy standards.
The jerky deceleration also is more noticeable because of the engine's increased power. The new LS 400 has 260 horsepower vs. 250 for the old.
Some dealers said that only a handful of owners are noticing the problem. Other dealers said they've received no complaints.
At JM Lexus in Margate, Fla., the largest Lexus dealer in the country, all the complaints have been from repeat owners.
''You have to be a sensitive driver to pick up on it,'' said David Mullen, general manager of JM Lexus. ''Those who drove the old LS 400 have become used to that smoothness. They'll jump on any feeling that's not common to the Lexus they're used to driving.''
April 06, 1995|By Automotive NewsLOS ANGELES — Lexus is quietly fixing some of its all-new LS 400 cars because they jerk when decelerating.
Lexus is replacing the entire engine management computer for owners who report a problem. The fix takes about 30 minutes and is covered under warranty.
The cost to Lexus is ''several hundred dollars'' per vehicle, said Gordon Rush, national service operations manager.
The ''throttle-shock condition'' could affect about 8,000 LS 400s built before February. Since then, a revised engine control unit has been installed on the assembly line in Tahara, Japan.
Lexus spokesman Mike Michels said the condition is not a defect and that most LS 400 owners ''don't experience it or find it objectionable.
''There's no adverse effect on reliability or safety. There are no durability implications whatsoever,'' Michels said.
He estimated that a couple thousand owners would notice the condition.
Michels said Lexus' fix goes beyond the seriousness of the problem. He compared it to Lexus' recall of the first LS 400 cars in 1989 after one car had a cruise control button malfunction.
The problem occurs when drivers quickly remove their foot from the gas pedal between 45 and 60 mph. The engine's electronic control unit is supposed to put the vehicle into a ''glide'' mode with slight engine braking, but instead there is a slight bump or jolt.
Initially, the control unit was programmed to take several driving and shifting patterns into consideration. Under aggressive driving, fuel flow would shut off immediately if drivers quickly took their foot off the gas, then the transmission's torque converter would unlock.
That caused the jerky deceleration, because the engine revolutions would slow to zero and force a drag on the transmission. The new control unit first unlocks the torque converter, then shuts off the fuel flow.
Michels said the 1995 LS 400's control unit initially was revised to help the car meet stricter emissions and fuel-economy standards.
The jerky deceleration also is more noticeable because of the engine's increased power. The new LS 400 has 260 horsepower vs. 250 for the old.
Some dealers said that only a handful of owners are noticing the problem. Other dealers said they've received no complaints.
At JM Lexus in Margate, Fla., the largest Lexus dealer in the country, all the complaints have been from repeat owners.
''You have to be a sensitive driver to pick up on it,'' said David Mullen, general manager of JM Lexus. ''Those who drove the old LS 400 have become used to that smoothness. They'll jump on any feeling that's not common to the Lexus they're used to driving.''
11-28-10, 06:14 PM
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Thanks for this post. I have had this throttle body jerky deceleration issue for years. Will the dealers still look to take care of loyal lexus owners. I have a 95 with 214K on it. She is a great car and I have no plans of getting rid of her. This issue is annoying however..
11-29-10, 11:18 PM
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Mine has had this problem as well for the 4 years ive owned it. Time to go find an ecu I guess.
EDIT: picked up a 89661-50234 on ebay for 100 bucks. Wish me luck.
EDIT: picked up a 89661-50234 on ebay for 100 bucks. Wish me luck.
Last edited by Rey; 11-30-10 at 12:15 PM.
02-13-13, 05:20 PM
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Lexus Champion
4. If you have off-throttle shock and cold and/or hot coolant idle speed variation then replace the IACV first. You can disassemble, clean, and lubricate the servomotor by that thats some skill or DIY persistence.
02-13-13, 05:26 PM
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Link: http://articles.orlandosentinel.com/...rque-converter
Lexus spokesman Mike Michels said the condition is not a defect and that most LS 400 owners ''don't experience it or find it objectionable.
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''You have to be a sensitive driver to pick up on it,'' said David Mullen, general manager of JM Lexus. ''Those who drove the old LS 400 have become used to that smoothness. They'll jump on any feeling that's not common to the Lexus they're used to driving.''
Lexus spokesman Mike Michels said the condition is not a defect and that most LS 400 owners ''don't experience it or find it objectionable.
---------------------------------------------------
''You have to be a sensitive driver to pick up on it,'' said David Mullen, general manager of JM Lexus. ''Those who drove the old LS 400 have become used to that smoothness. They'll jump on any feeling that's not common to the Lexus they're used to driving.''
#2: Every person that has ridden in my 95' comments on it "What the hell was that!?"
Too bad they don't just pony up the dough and hook the 95 owners up.. The least they could do is cut us a deal on the new ECUs that i'm sure are not selling like hot cakes and sitting on a warehouse shelf somewhere due to the $1700+ price!
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02-13-13, 06:52 PM
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Lexus Champion
Too bad they don't just pony up the dough and hook the 95 owners up.. The least they could do is cut us a deal on the new ECUs that i'm sure are not selling like hot cakes and sitting on a warehouse shelf somewhere due to the $1700+ price!
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