I am receiving a computer code of P1587 Throttle Control Unit Modulated Command Malfunction on my 2000 S type Jaguar.Does anyone know what exactly what Throttle Control Unit Modulated Command Malfunction means. Thank you!
Not an expert, but it could mean there is a problem with the control signal being sent to the throttle control unit. Your car probably has an electronic throttle (a motor controls it instead of a cable to the gas pedal). I don't know if this code means signal problems from the computer to the throttle unit or if it means a problem with the gas pedal signal. You might have to replace any of the following: the gas pedal, the throttle body, throttle body harness, or possibly the computer itself. I would hook up a scan tool and confirm there is a good, smooth signal from the gas pedal. I would also take the throttle body off, clean it, and check the servo gearing (sometimes the gears wear out). It should open and close smoothly by hand (there will be resistance though).
