AM Radio - Noise

GROUP REF.: Accessories

BULLETIN NO.: 479601

DATE: March. 1994

SUBJECT:
AM RADIO NOISE (REPLACE IGNITION CONTROL MODULE)

MODELS:
1993 CADILLAC ALLANTE
1993-1994 CADILLAC ELDORADO AND SEVILLE
1994 CADILLAC CONCOURS
EQUIPPED WITH 4.6L NORTHSTAR ENGINE
(RPOs LD8 AND L37; VINs Y AND 9)

CONDITION:
Some owners may experience "static" noise during the operation of their vehicle, while the radio is in use, in the AM radio band.

CAUSE:
This condition may be caused by Electro Magnetic Interference emitted from the ignition Control Module.

CORRECTION:
To repair this condition, replace the Ignition Control Module with a new capacitor equipped ignition Control Module P/N 10477276, ICM Bracket P/N 10472128, Bolt P/N 11516186 and Ground Strap P/N 12164812. The ground strap will be installed between the Ignition Control Module and the engine block, using the following procedure:

NOTICE:
The new capacitor equipped DIS Module, Bracket, Bolt and Ground Strap must be used together to correct the "AM Radio Noise Condition." If these components are not used simultaneously, the "AM Radio Noise" will still be present and possibly amplified.

For identification purposes, the new DIS Module Bracket used to correct this condition is silver in color and requires the use of the new ground strap. The previous DIS Module Bracket is black in color and must not be used with the ground strap. The above mentioned components went into production at the Hamtramck Assembly Plant 2/4/94.




Remove or Disconnect (Figure 1)

1. Spark plug wires at Ignition Control Module Assembly.
2. Four electrical connectors at Ignition Control Module.
3. Four bolts retaining ICM Assembly to rear camshaft cover.
4. ICM Assembly from vehicle.
5. Ignition coils from ICM Assembly.
6. ICM from assembly bracket.

Install or Connect (Figure 1)

1. ICM to new assembly bracket.
2. Ignition coils to ICM Assembly.
3. Position "new" ICM Assembly on rear camshaft cover and hand start number 1, 2, and 3 bolts.
4. Hand start remaining bolt # 4 as shown in Figure 1 through eyelet in ground strap.

Tighten
Four bolts to 12 Nm (106 lb.in.).

5. Four electrical connectors at ICM.
6. Spark plug wires at ICM Assembly.
7. Attach bolt through remaining end of ground strap and install in right bank cylinder head (Figure 1).
8. Torque bolt to 11 Nm (97 lb.in.).

SERVICE PARTS INFORMATION:
Refer to the following part numbers when ordering parts for the AM RADIO NOISE condition.

Description Part Number

Ignition Control Module 10477276
ICM Bracket 10472128
Bolt 11516186
Ground Strap 12164612

NOTE:
Whenever replacement of the Ignition Control Module is necessary on a 1993 to 1994 Northstar Engine, the entire AM RADIO NOISE package must be used.

Parts are currently available from GMSPO.

WARRANTY INFORMATION:

Labor Operation: T 3455
Labor time: 0.4 hour