Standard Speed Control

WARNING: This page is about a different car, the 2018 Jaguar XF, 2017 Jaguar XF, and 2016 Jaguar XF. However, it is still accessible from the selected car via links, so may be relevant.

The speed control system is integrated with the engine management system and uses fueling intervention to automatically maintain a set vehicle speed. Once engaged, the system can also be used to accelerate the vehicle without using the accelerator pedal.

The speed control system comprises the following main components:

'+' and '-' (SET/increase speed and decrease speed) switches - located on right steering wheel switchpack
'RES' (resume) switch - located on right steering wheel switchpack
'CAN' (cancel) switch - located on right steering wheel switchpack
Clockspring (CLKSPG)
Speed control warning indicator in Instrument Cluster (IC).

The speed control system also uses inputs from the brake pedal switch, clutch pedal position sensor (manual transmission only), the Accelerator Pedal Position (APP) sensor, the Power Control Module (PCM) and the Anti-lock Brake (ABS) system control module.

The speed control is operated by the driver using only the switches on the right steering wheel switchpack. When speed control is active, the PCM regulates the output signals to the fuel injectors to adjust the fuel supply as required to maintain the set speed.

During speed control operation, the PCM controls vehicle speed by adjusting fuel injection duration and timing. When the accelerator pedal is pressed with speed control active, the PCM outputs a calculated throttle angle signal in place of the actual throttle angle signals produced by the APP sensor. The calculated throttle angle is derived from fuel demand based on the torque required to overcome the rolling resistance (vehicle motion drag).

The minimum set speed for speed control is 20 mph (32 km/h).

Speed control is automatically suspended if the following conditions apply:

Vehicle speed falls below 15 mph (24 km/h)
The brake pedal is pressed
The clutch pedal is pressed (manual transmission only)
The cancel button is operated
Neutral, park or reverse gear is selected
The Electric Park Brake (EPB) is applied
The difference between actual speed and the set speed is too great
If the accelerator pedal is used to accelerate beyond the set speed for too long (more than 5 minutes)
The Anti-lock Brake (ABS) system logs a Diagnostic Trouble Code (DTC) fault.
System error causes shut-off
All surface progress control is selected.

There are four standard speed control switches located on the right steering wheel switchpack:

Set speed '+' (increase speed) switch
Decrease speed '-' switch
Cancel 'CAN' switch
Resume 'RES' switch.

The standard speed control switches are located on the right steering wheel switchpack. The switches are resistive ladder type switches which vary the resistance of a voltage signal sent to them. The resistive ladder is wired to a control module within the right steering wheel switchpack. The control module is a Local Interconnect Network (LIN) node, which transmits the data to the Body Control Module/Gateway Module (BCM/GWM) assembly which passes the data onto the High Speed (HS) Controller Area Network (CAN) powertrain systems bus. In the event of the PCM logging a speed control switch fault DTC, fault finding should start at the right steering wheel switchpack and CLKSPG. The PCM diagnostic detects that the right steering wheel switchpack has not provided an updated live counter.