Symptom Chart

WARNING: This page is about a different car, the 2007 Mercury Mariner and 2007 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

Symptom Chart

Condition	Possible Sources	Action
No communication with the audio unit	Circuitry Audio unit	REFER to MODULE COMMUNICATIONS NETWORK article to continue diagnosis of the communication circuits.
The audio unit is inoperative/does not operate correctly	Fuse(s) Circuitry Audio unit	Go to Pinpoint Test F .
The CD changer is inoperative/does not operate correctly	Fuse Circuitry Audio unit Audio corporate protocol (ACP) module CD changer	Go to Pinpoint Test G .
Poor reception	Antenna Antenna cable(s) Audio unit	Go to Pinpoint Test I .
Continuous SEEK/SCAN in AM/FM	Antenna Antenna cable(s) Audio unit	Go to Pinpoint Test I .
No sound from one or more of the speakers (not all speakers)	Circuitry Speaker(s) Audio unit	Go to Pinpoint Test J .
No sound from all speakers	Circuitry Audio unit Smart junction box (SJB)	Go to Pinpoint Test H .
Poor quality/distorted sound from one or more speakers (not all speakers)	Circuitry Speaker(s) Audio unit	Go to Pinpoint Test J .
Poor quality/distorted sound from all speakers	Circuitry Antenna Antenna cable(s) Radio frequency interference suppression equipment Noise suppression equipment Ignition system Charging system Audio unit	Go to Pinpoint Test M .
The subwoofer is inoperative	Fuse Circuitry Subwoofer Subwoofer amplifier Audio unit	Go to Pinpoint Test K .
Loud popping sound when cycling the ignition switch	Circuitry Subwoofer amplifier Audio unit SJB	Go to Pinpoint Test L .
Navigation system does not operate correctly	Fuse(s) Circuitry Audio unit	Go to Pinpoint Test N .
Navigation system does not operate correctly - no reverse tracking	Circuitry Audio unit	Go to Pinpoint Test O .
Navigation system does not operate correctly - no speedometer signal	Circuitry Audio unit Anti-lock brake system (ABS) module	Go to Pinpoint Test P .
Navigation system does not operate correctly - no global positioning system (GPS) antenna signal	Audio unit GPS antenna	Go to Pinpoint Test Q .
Navigation system does not operate correctly - the display screen is inoperative	Fuse(s) Circuitry Audio unit	Go to Pinpoint Test N .
Navigation system does not operate correctly - Navigation system is inaccurate	Circuitry Map compact disc (CD) Calibration Audio unit	Go to Pinpoint Test R .
Navigation system does not operate correctly - the fuel economy and energy flow screens do not display real time data	Circuitry Audio control protocol (ACP) module Instrument cluster	Go to Pinpoint Test S .
Navigation system does not operate correctly - the fuel economy and energy flow screens cannot be selected or do not remain selected	Circuitry ACP module Audio unit	Go to Pinpoint Test T .