Pinpoint Test E: Poor Reception - AM/FM
Information and Entertainment System
Pinpoint Tests
Pinpoint Test E: Poor Reception - AM/FM
Refer to Wiring Diagrams Set 130, Audio System for schematic and connector information. Diagrams By Number
Normal Operation
The radio antenna receives AM and FM radio waves and sends them to the Audio Control Module (ACM).
The noise suppression equipment reduces engine ignition and electrical systems interference transmitted through the speakers.
- DTC B2103 (Antenna Not Connected) - sets during the antenna connected test (part of the ACM self-test) when the signal strength is less than the pre-configured threshold value. In order for this DTC to set, the audio system must be tuned to AM, and the self-test must be run with the scan tool.
This pinpoint test is intended to diagnose the following:
- Antenna
- Antenna cable
- Charging system
- Ignition system
- Noise suppression equipment
- ACM
PINPOINT TEST E: POOR RECEPTION - AM/FM
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
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E1 CHECK THE AUDIO SYSTEM RECEPTION
- Operate the audio system in radio tuner (AM/FM) mode.
- Check the reception with the engine running, and with the engine off.
- Does the poor reception only occur with the engine running?
Yes
GO to E2.
No
GO to E7.
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E2 CHECK THE NOISE SUPPRESSION EQUIPMENT
- Check all required noise suppression equipment (including the ACM ground strap) and the radio frequency interference suppression bond for security, cleanliness, and metal-to-metal contact.
- Are the connections clean, secure, and in metal-to-metal contact?
Yes
GO to E3.
No
CLEAN and SECURE the connections, or INSTALL new noise suppression equipment as needed. TEST the system for normal operation.
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E3 CHECK THE CAPACITOR MOUNTING AND CONNECTING CIRCUITS
- NOTE: The capacitor mounting points are used to complete the electrical circuit and must be mounted securely to clean surfaces.
- Check the mounting and connecting circuits of the radio ignition interference capacitor for security, cleanliness, and metal-to-metal contact.
- Are the contacts clean, secure, and in metal-to-metal contact?
Yes
GO to E4.
No
CLEAN and SECURE the connections, or INSTALL a new radio ignition interference capacitor as necessary. TEST the system for normal operation.
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E4 CHECK THE RADIO INTERFERENCE CAPACITOR
- Check the operation of the radio interference capacitor by installing a known good component.
- Start the vehicle.
- Operate the audio system in radio tuner (AM/FM) mode.
- Is the reception OK?
Yes
INSTALL a new radio interference capacitor. TEST the system for normal operation.
No
INSTALL the original radio interference capacitor. GO to E5.
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E5 CHECK THE GENERATOR
- Ignition OFF.
- Disconnect the wiring harness from the generator voltage regulator.
- Start the engine.
- Operate the audio system in radio tuner (AM/FM) mode.
- Is the reception OK?
Yes
INSTALL a new generator. TEST the system for normal operation.
No
GO to E6.
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E6 CHECK THE IGNITION CIRCUITS
- Ignition OFF.
- Connect the wiring harness to the voltage regulator.
- Check the ignition circuits for correct routing, grounding, and integrity of the connections.
- Are the ignition components OK?
Yes
USE a jumper cable to ground various parts of the vehicle to the frame (for example: engine, fenders, quarter panels, stone deflectors, air cleaner, body sheet metal). When the noise is eliminated, PROVIDE a permanent ground where necessary.
TEST the system for normal operation.
No
REPAIR the ignition system as necessary. TEST the system for normal operation.
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E7 CHECK THE ANTENNA COAXIAL CABLE
- Ignition OFF.
- Disconnect: Antenna Coaxial Cable (At Antenna).
- Disconnect: Antenna Coaxial Cable (At ACM).
- Measure the resistance of the antenna coaxial cable core between the antenna and the ACM.
- Is the resistance less than 2 ohms?
Yes
GO to E8.
No
INSTALL a new antenna cable. REFER to Antenna Cable - AM/FM Antenna Cable - AM/FM. TEST the system for normal operation.
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E8 ISOLATE THE ANTENNA
- Connect: Antenna Coaxial Cable (At ACM).
- Substitute the antenna for a known good antenna.
- Operate the audio system in radio tuner (AM/FM) mode.
- Is the reception OK?
Yes
INSTALL a new antenna. REFER to Antenna Service and Repair. TEST the system for normal operation.
No
INSTALL the original antenna. GO to E9.
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E9 ISOLATE THE ANTENNA CABLE
- Ignition OFF.
- Install a new antenna cable. Refer to Antenna Cable - AM/FM Antenna Cable - AM/FM.
- Operate the audio system in radio tuner (AM/FM) mode.
- Is the reception OK?
Yes
The system is operating correctly at this time. The concern was caused by an inoperative antenna cable.
No
GO to E10.
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E10 CHECK FOR CORRECT ACM OPERATION
- Disconnect all the ACM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the ACM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new ACM. REFER to Audio Control Module (ACM) Audio Control Module (ACM). TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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