Many conditions that affect an audio system operation can be corrected without removing components from the vehicle. Before attempting to diagnose an audio system problem be sure that the battery is fully charged. Batteries supplying less than 10.5 volts will cause erroneous diagnosis of the audio system.
The audio system uses a serial data line to coordinate the operation of several independent units into an audio system. The serial data line allows each of the units to communicate with the others by digitally encoded voltage pulse streams or serial data. Access to the data is available at the data link connector (DLC) located under the left hand side of the instrument panel near the steering column. Read the data with a scan tool.
To help pinpoint the problem, always determine the exact nature of the audio system problem. Determine the following:
| • | Is the condition intermittent or is the condition constant? |
| • | Does it occur with the engine off or does it occur with the engine running? |
| • | Does it occur with the vehicle parked or does it occur with the vehicle moving? |
Static and Noise
Ground strap connections must be clean and tight. Spark plug cables must be TVRS-type and in good condition. Resistance-type spark plugs must be used.
The A/C blower motor has a built-in capacitor. Extra electrical equipment added to the vehicle could cause static if not properly grounded or if the wiring is improperly routed.
Reception of weak FM stations will be affected by nearby buildings, vehicle speed and direction. Flutter and fading conditions are characteristic of weak FM signals.
Popping Noise
Operating devices such as the turn signals, the stoplamps, the cigar lighter, etc. may cause a popping noise on distant (weak) AM signals.
