Radio Interference

Use aluminum foil tape or nickel tape in order to shield against magnetically induced interference when shielding the following components:
^ The dash
^ The wires
^ The hoses
Most hoses are conductive unless the hoses have a white stripe.

Vary the following ground techniques for optimum grounding results:
^ Add a ground at both ends of the tape.
^ Add a ground to just one end of the tape.
^ Do not add ground to the tape.

Complete the following steps when shielding a harness with tape:
^ Attach a ground strap to the end of the tape.
^ Wrap the strap 360 degrees around the tape.
^ Secure the other end of the strap to a known good chassis ground.

If possible, correct any interference at the source of the interference.

Apply suppression carefully. The following wires can be suppressed:
^ The battery wires
^ The ignition wires
Signal wires cannot be suppressed.

The following wires are examples of signal wires that cannot be suppressed:
^ The sensor outputs
^ The clock
^ The communication circuits

After you apply suppression, inspect all of the vehicle systems for correct operation.

Interference is usually eliminated with the following procedures:
^ Shielding
^ Grounding
^ Suppressing

Use capacitors in order to correct the following conditions:
^ Switch pops
^ Low frequency noise

Use filters in order to correct the following conditions:
^ High frequency whines
^ Static

Whenever possible, make a test harness that includes filters and capacitors. Always verify that a repair is effective and that the systems operate correctly before you permanently install a fix.

Use one of the following capacitor applications for an audible pop that is induced by a switching operation:
^ Add a capacitor across the contacts of the switch.
^ Add a capacitor from the hot side of the switch to the ground.
^ Add a capacitor to each side of the switch to the ground.

Complete the following inspections if the condition is present only when the ignition is in the RUN position and the engine is running:
^ Inspect the integrity of the ignition system. Refer to Engine Controls.
^ Inspect the integrity of the engine compartment grounds.
^ Inspect for the following conditions that may cause noise or poor reception:
- Malfunctioning relays
- Malfunctioning solenoids
- Malfunctioning system components
^ Inspect the integrity of the ground for the component that is causing the complaint.

Perform the Antenna System test for noise or poor reception. Repair the system as needed. Refer to Antenna Poor Reception (W/O UV7) or Antenna Poor Reception (W/ UV7) or Antenna Poor Reception (W/O UV7) or Antenna Poor Reception (W/ UV7) for diagnosis.

For a description of the RPO Code(s) shown in this article/images refer to the RPO Code List found at Vehicle/Application ID RPO Codes