Diagnostic System Check

Radio/Audio System Diagnostic System Check (Part 1 of 2):

Radio/Audio System Diagnostic System Check (Part 2 of 2):

CIRCUIT DESCRIPTION
The Radio/Audio System Diagnostic System Check is an organized approach to identify problems associated with the radio and radio amplifier. This check must be the starting point for any complaint, and will direct you to the next logical step in diagnosing the complaint. The radio and radio amplifier are very reliable components and are not likely the cause of the malfunction. Most system complaints are linked to faulty wiring and connectors, and occasionally to components. Understanding the radio/audio system and using the tables correctly will reduce diagnostic time and prevent unnecessary parts replacement.

DIAGNOSTIC AIDS
^ The following conditions may result in an intermittent operation of the radio or radio amplifier with no DTCs stored:
- Any condition which results in the interruption of power to the radio or radio amplifier
- Out of range battery positive voltage or ignition voltage
Specification
Normal radio and radio amplifier operating voltage: 10.5-16.0 V
- A loose or damaged ground(s)
- An open or shorted Class 2 serial data line
^ An intermittent failure in the electronic system may be very difficult to detect and to accurately diagnose. The radio and radio amplifier test for different malfunctions under different vehicle conditions. For this reason, a thorough test drive is often needed in order to repeat a malfunction. If the system malfunction is not repeated during the test drive, a good description of the complaint may be very useful in locating an intermittent malfunction. Faulty electrical connections or wiring causes most intermittent problems. When an intermittent condition is suspected, check the suspected circuits for the following conditions:
- Poor mating of connector halves or backed out terminals
- Improperly formed or damaged terminals
- Wire chafing
- Poor wire-to-terminal connections
- Dirty or corroded terminals
- Damage to connector bodies
^ Use the J 35616-A whenever a diagnostic procedure requests probing or checking a terminal. Using this adapter ensures that no damage to the terminal occurs, and provides an idea of whether contact tension is sufficient.
^ If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This movement can often cause the malfunction to occur. Perform a thorough inspection of all related wiring and connectors pertaining to the history DTC stored. Refer to Intermittents and Poor Connections.
^ Exit all scan tool tests before cycling the ignition OFF to ON unless the scan tool instructions direct otherwise. Follow the operating instructions in the scan tool operator's manual. Failure to follow these instruction may set DTCs, cause vehicle system malfunctions, set false DTCs, or cause scan tool malfunctions.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table:
1. Determines if communication can be established with the radio (IRC) and Radio Amplifier (AMP).
4. Checks for stored radio and radio amplifier DTCs.
5. Checks for stored Loss of Class 2 Serial Data Communication DTCs.
6. Determines if communication can be established with other modules connected to the Class 2 serial data line.
7. Checks for an open radio power fuse.
8. Checks the radio power circuit. If the measured voltage is not in the specified range, there is an open in the power circuit.
9. Checks the radio ground circuits. If the measured voltage is not in the specified range, there is an open in the radio ground circuit.
14. Checks for an open radio amplifier power fuse.
15. Checks the radio amplifier power circuit. If the measured voltage is not in the specified range, there is an open in the module power circuit.
16. Checks the radio amplifier ground circuit. If the measured voltage is not in the specified range, there is an open in the radio amplifier ground circuit.