Volvo Repair Questions? Ask a Mechanic for Answers ASAP
When you say the diagnostic showed the Throttle Pedal Sensor was faulty what exactly do you mean? There is a code that shows Throttle Pedal Sensor?
If so you need to complete the diagnostic! When you retrieve a fault code using a diagnostic code reader the code points to the area in which you need to look at. So in your case it points to the Throttle Pedal Sensor. The code you have retrieved could mean one of three things:
The first stage would be to see what you have at the Throttle Pedal Sensor as per the Volvo Service Manual. It will no doubt give you items like Voltage and Earth to check at the connector and maybe a resistance check of the sensor itself. You would then have to carry out continuity checks of the wiring from the sensor to the module. If all of that checks out ok then the only thing it can be is the module itself.
The Workshop Manuals detailing the testing needed is available here: Volvo B2B
The Engine Management Light will only come on if it notices a fault several times in a row. For example 2nd Trip Detection which is usual for most Engine Management Faults means that the Warning Light will only come on if the fault occurs on two consecutive trips. If the fault doesn't reoccur then the light will not come on and the fault will just be recorded as a Past Code.