10’ LS460 Sport - Cruise Control Quirk
12-26-18, 07:05 AM
#1
10’ LS460 Sport - Cruise Control Quirk
I hope everyone had a Merry Christmas!
I’m curious if anyone else here has experienced this issue with cruise control. My Lexus is a 2010 LS460 Sport model.
Ive owned the car for about 2 months now, went to work this morning and noticed while cruising with cruise control on, going down a hill coasting the RPM’s hunt moving up and down maybe 800-1000rpm changes. It seems as if the ECU doesn’t know whether to fully remove throttle or add a slight amount and it’s jumping between on and off. It never does this while cruising on flat roads or up hills, only on decel. No check engine codes.
I’m going to try disconnecting the battery to see if the ECU / TCU needs to relearn. Car is smooth as can be any other time. I was reading that Toyota / Lexus does offer firmware updates periodically but the closest Lexus dealer is 2.5 hours away.
Thoughts? Thanks!
I’m curious if anyone else here has experienced this issue with cruise control. My Lexus is a 2010 LS460 Sport model.
Ive owned the car for about 2 months now, went to work this morning and noticed while cruising with cruise control on, going down a hill coasting the RPM’s hunt moving up and down maybe 800-1000rpm changes. It seems as if the ECU doesn’t know whether to fully remove throttle or add a slight amount and it’s jumping between on and off. It never does this while cruising on flat roads or up hills, only on decel. No check engine codes.
I’m going to try disconnecting the battery to see if the ECU / TCU needs to relearn. Car is smooth as can be any other time. I was reading that Toyota / Lexus does offer firmware updates periodically but the closest Lexus dealer is 2.5 hours away.
Thoughts? Thanks!
12-26-18, 07:47 AM
#2
Lexus Fanatic
Interesting. That happened with my GS, and is well documented on the GS forum, but neither of my LS460s have behaved that way...
12-26-18, 09:15 AM
#3
I drive the same highway daily, same route and speed so I’m not sure what has changed to cause the ECU RPM to “hunt” on decel. The car downshifts as it should if the steep of the slope starts increasing the cruise control set speed. Maybe it was just a odd anomaly because grabbing lunch 30 minutes ago the vehicle didn’t show any signs of it.
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