Some 2011-2012 Ford F-Super Duty 250-450 trucks equipped with a 6.7L diesel engine may exhibit a buzzing noise from under the hood while the engine is running and/or for up to 30 seconds after the engine is shut off. This concern may be due to the wastegate control valve vacuum harness causing the wastegate control valve to resonate.
1. Does the wastegate control valve emit a buzzing noise with engine running and/or for up to 30 seconds after shut off?
a. No: this bulletin does not apply.
b. Yes: proceed to Step 2.
2. With the buzzing noise present, disconnect the vacuum hoses from the wastegate control valve. Does the buzzing noise stop?
a. No: this bulletin does not apply. Refer to Powertrain Control/Emission Diagnosis manual for normal diagnostics.
b. Yes: proceed to Step 3.
3. Replace the wastegate control valve vacuum harness.
a. Remove the throttle body.
b. Remove the air cleaner outlet pipe.
c. Remove three wire harness retainers and position aside the engine wiring harness.
d. Disconnect the vacuum harness and remove.
e. Install a new vacuum harness and follow reverse procedure for installation.
The new vacuum harness is available as P/N BC3Z-9D430-E.