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 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:
-
Determines if communication can be established with the radio (IRC) and radio amplifier (AMP).
-
Checks for stored radio and radio amplifier DTCs.
-
Checks for stored Loss of Class 2 Serial Data Communication DTCs.
-
Determines if communication can be established with other modules connected to the Class 2 serial data line.
-
Checks for an open radio power fuse.
-
Checks the radio power circuit. If the measured voltage is not in the specified range, there is an open in the power circuit.
-
Checks the radio ground circuits. If the measured voltage is not in the specified range, there is an open in the radio ground circuit.
-
Checks for an open radio amplifier power fuse.
-
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.
-
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.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Does the scan tool communicate with both the radio and the radio amplifier? | -- | |||
2 | In step 1, did the scan tool communicate with the radio amplifier but not the radio? | -- | ||
3 | In step 1, did the scan tool communicate with the radio but not the radio amplifier? | -- | ||
Are any DTCs stored by the radio or radio amplifier? | -- | Go to Radio/Audio System Check | ||
Are any Loss of Class 2 Serial Data Communication DTCs set? (Loss of Class 2 Serial Data Communication DTCs have the form UXXXX.) | -- | Go to Diagnostic Trouble Code (DTC) List/Type in Body Control System | ||
Attempt to establish communication with the other modules connected to the same serial data line (PCM, RFA, IPC, etc.). Does the scan tool communicate with the other modules? | -- | Go to Diagnostic Trouble Code (DTC) List/Type in Body Control System | Go to Scan Tool Does Not Communicate with Class 2 Data Line in Wiring Systems | |
Is the voltage within the specified range? | 10-15 V | |||
Is the voltage within the specified range? | 10-15 V | |||
Connect a DMM between radio connector terminal E16 and battery positive voltage (B+). Is the voltage within the specified range? | 10-15 V | |||
10 | Repair the open in the battery feed to the AUDIO fuse. If the fuse is open, locate and repair the short to ground in CKT 2240 (ORN). Is the circuit repair complete? | -- | -- | |
11 | Repair the open in ground CKT 651 (BLK/WHT). Is the circuit repair complete? | -- | -- | |
12 | Repair the open in CKT 2240 (ORN). Is the circuit repair complete? | -- | -- | |
13 | Check the radio connector for poor terminal contact. If OK, replace radio. Refer to Radio Replacement . Is the replacement complete? | -- | -- | |
Is the voltage within the specified range? | 10-15 V | |||
Is the voltage within the specified range? | 10-15 V | |||
With a DMM connected to battery positive voltage (B+), probe ground circuit CKT 651 (BLK) at the radio amplifier connector. Is the voltage within the specified range? | 10-15 V | |||
17 | Repair the open in the battery feed to the AUDIO AMP fuse. If the fuse is open, locate and repair the short to ground in CKT 1242 (RED). Is the circuit repair complete? | -- | -- | |
18 | Repair the open in ground CKT 651 (BLK). Is the circuit repair complete? | -- | -- | |
19 | Repair the open in CKT 1242 (RED). Is the circuit repair complete? | -- | -- | |
20 |
Is the replacement complete? | -- | -- | |
21 |
Are all DTCs cleared? | -- | Go to Radio/Audio System Check | -- |
