P0638

P0638 on Alfa Romeo — Engine warning light with loss of performance

All the fault codes

Code P0638 reports incorrect operation of the throttle actuator control. On the Alfa Romeo Giulietta 2.0 JTDM it appears together with several other intake system codes and shows up as the engine warning light on and a loss of performance.

System
Fuel injection
Component
Throttle body
Fault
The engine warning light comes on, with a loss of performance.
Typical symptoms
  • Engine warning light on
  • Loss of performance
  • One or more intake system codes are stored together in the diagnostic memory
Vehicles affected
  • Alfa Romeo Giulietta 2.0 JTDM 16v
Main code
  • P0638 Throttle actuator control, incorrect control operation
Related codes
  • P0045 Boost pressure limiting solenoid valve, incorrect operation or open circuit
  • P0101 Mass air flow sensor, incorrect target value
  • P0135 Oxygen sensor heater circuit 1, bank 1, signal fault
  • P1540 Variable-displacement engine oil pump, control actuator
  • P2008 Intake air control solenoid valve, bank 1, circuit open
  • P2014 Intake air control solenoid valve position sensor or contact, bank 1, incorrect operation
  • P2620 Throttle position sensor, output signal, circuit open

On this fault the diagnostic tool often returns several codes together.

Solution

See the repair procedure verified on Sema Repair.

Go to the application · not a customer yet?

The cause and the repair are on Sema Repair

On Sema Repair this code is linked to verified case studies, with the confirmed cause case by case, the job step by step, indicative times, the manufacturer's notes and a photograph of the component with the point of intervention highlighted.