Service Throttle Soon Indicator Lamp (Diesel Engines)

Vehicles with diesel engines have an electronic throttle control system. Throttle cables are no longer used with these vehicles.

An electronic throttle pedal assembly sends signals to the Powertrain Control Module (PCM). The PCM receives the throttle position signal and compares this with information such as road speed and transmission range. The PCM then signals a solenoid on the injector pump assembly. This keeps precise control over the entire diesel throttle system.

The Service Throttle Soon lamp is in the lower right corner of the instrument cluster. This lamp turns on when the ignition switch is in the RUN position and the engine is off. The lamp should turn off 1-5 seconds after the engine starts. If the lamp stays on, or turns on while driving, this may require service to the electronic throttle system. Refer to A Powertrain On Board Diagnostic (OBD) System Check in Computers and Control Systems.