Throttle Actuator Control Range/Performance Bank 1

Where it lives

For P0638, start at the actuator the description names. The description of P0638 puts it on bank 1.

Check these first

• Carbon buildup on the bank 1 throttle plate
• A failed throttle actuator motor on bank 1
• A failed throttle position sensor on bank 1
• A wiring fault on the bank 1 throttle body
• A faulty ECM

What to do next

1. Watch the throttle command and position on bank 1 while revving
2. Clean carbon from the bank 1 throttle body
3. Inspect the bank 1 throttle body connector and wiring
4. Compare both throttle tracks on bank 1
5. Replace the bank 1 throttle body if it does not follow the command
6. Clear the code and retest

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