Radio - Weak or Noisy FM Reception

Classification:
SA96-002

Reference:
ITB96-010

Date:
February 7, 1996

DIVERSITY AND MAST ANTENNA ISOLATION TECHNIQUE

APPLIED VEHICLES:
1993-1996 Q45 (G50)
1993-1996 J30 (JY32)
1996 I30 (CA32)

APPLIED DATE:
All Q45's built February 1993 and later
All J30's
All I30's

SERVICE INFORMATION

Weak or noisy FM radio reception (AM reception OK) in the above listed vehicles with diversity type Clarion radios may be diagnosed by isolating the windshield antenna, or the mast antenna.

SERVICE PROCEDURE

To isolate the windshield (sub) antenna, use the following procedure:

1. Turn the ignition key to "ON".

2. Push and hold both radio pre-set buttons # 4 and # 6 at the same time, then press the volume knob to turn the radio on.

NOTE:
On late model vehicles, "SU" may flash on the radio display to confirm the radio is receiving through the diversity antenna only.

3 Check the reception of specific frequencies as described in the repair order.

To isolate the mast (main) antenna, use the following procedure:

1. Turn the ignition key to "ON".

2. Push and hold both radio pre-set buttons # 1 and # 3 at the same time, then press the volume knob to turn the radio on.

NOTE:
On late model vehicles, "MA" may flash on the radio display to confirm the radio is receiving through the mast antenna only.

3. Check the reception of specific frequencies as described in the repair order.

4. It the weak or noisy reception occurs only when the radio is receiving through the windshield antenna, follow the procedure in the appropriate service manual for "Window Antenna Repair".

If the weak or noisy reception occurs only when the radio is receiving through the mast antenna, carry out the following:





A. Inspect the antenna ground (antenna nut) at the power antenna location. If the nut is loose, use a suitable tool to torque the antenna nut to 27-35 in-lb. For a satisfactory ground, there must be sufficient force to compress the foam and permit the pins on the antenna base to contact the vehicle body.

B. Inspect the feeder cable for shorts or opens.