Audio Sys. - Poor FM Radio Reception With Engine Running
91 Poor FM radio reception20 12 23
2029899/1
June 18, 2012.
Affected Vehicles
Condition
Customer states there are background noises on the radio in FM when the engine is running, or FM radio reception is poor.
This bulletin does not apply if radio reception is also poor when the engine is not running, or if the fuel pump is not active.
Technical Background
High frequency oscillations can be generated in the signals between the fuel pump control unit and the pump itself. This leads to radio interference in the FM frequency range, mainly when there is a weak radio signal.
The complaint only occurs when the engine is running and stops when the fuel pump is switched off.
Production Solution
Optimized fuel pump control unit.
Service
1. Move the vehicle outdoors, and when the engine is running check whether the FM radio reception improves by removing the fuse of the control unit for fuel pump J538. The fuse is a 25A fuse, located in the second position in fuse block ST3 (Figure 1).
2. If the radio reception improves, replace the fuel pump control unit. If the radio reception does not improve, continue with standard diagnosis as this bulletin no longer applies.
Warranty
Additional Information
All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service manuals for the latest information.