| Issue ID | 627114 |
| Internal NHTSA # | 10188438 |
| Manufacurer | TOYOTA MOTOR CORPORATION |
| Brand | TOYOTA |
| Model | CAMRY HYBRID |
| Model Year | 2007 |
| File date | 01/08/06 |
| Component | VEHICLE SPEED CONTROL:CRUISE CONTROL |
| Product type code | VEHICLE |
| Description of the problem | The car's cruise control behavior on level ground is fine, but on rolling hills it's totally egregious, and indicates to me that this feedback control system may be close to instability and therefore potentially dangerous. I think that the control algorithm used is dreadfully sub-optimal, and has such long internal control-loop processing delays that its reactions to changing road conditions are alarming. What i find is the following behavior. The car substantially overshoots (by 10 mph or more) the set speed on the downhill portion of each hill, but then waits so long before reacting to the beginning of the next uphill portion, that it then undershoots the set speed by such a large amount (5 mph or more) that it has to "floor" the accelerator in order to catch up. Still on the uphill portion, it then proceeds to overshoot the set speed again, before finally settling down to the desired speed. This cycle of events repeats over and over again as one negotiates rolling hills with the cruise control "on." why is the internal loop delay so long? Why is the cruise control system not properly designed? (i happen to have expertise in control systems.) this control system really needs to be re-designed as a matter of priority! The cruise control's behavior could then be fixed by a simple firmware update. *jb |
| Vehicle Mileage at Failure | 250 |
| Number of Occurences | 1 |
| Source of the issue | NHTSA WEB SITE |
| City and State | WATERLOO, ONTARIO, CANADA, 00 |
| VIN pattern | JTNBB46KX73XXXXXX |
| Was vehicle invloved in a crash? | N |
| Was vehicle involved in a fire? | N |
| Was incedent reported to police? | N |
| Was medical attention required? | |
| Was part original equipment? | |
| No. of injured persons | 0 |
| No. of fatalities | 0 |
| Date of purchase | 21/07/06 |
| Was original owner? | Y |
| Anti-lock brakes | Y |
| Cruise control | Y |
| Number of cylinders | 4 |
| Drive train type | FWD |
| Transmission type | AUTO |
| Vehicle speed | 50 |
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| Was defective tire repaired? | |
| Date of manufacture | |
| Type of child seat code | |
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