For 1990-2009 cars

### Circuit Description

Battery power is supplied to the integrated radio controller (IRC) by the battery guard relay on circuit A52. The body control module (BCM) controls the output to the battery guard relay. The IRC monitors the voltage to determine if it is within a valid operating range.

### Conditions for Setting the DTC

DTC B1983 will set when the source voltage to the IRC falls below 9.5 volts for 1.2 seconds.

### Action Taken When the DTC Sets

• | Stores a DTC B1983 in the IRC memory.

• | A current DTC B1983 prevents the IRC from setting a Class 2 Loss of Serial Data, short to ground or battery DTC.

• | The IRC will not respond to any manual or memory inputs when the voltage is below 9.5 volts.

• | No driver warning message will be displayed for this DTC.

### Conditions for Clearing the DTC

• | DTC B1983 will clear when the source voltage is above 9.5 volts for 1.2 seconds.

• | DTC B1983 can also be cleared by using a scan tool.

### Diagnostic Aids

The IRC will not check the voltage level on this circuit for approximately 2 seconds following the engine crank mode. This insures that DTC B1983 will not set erroneously.

### Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

1. Clear all DTCs and cycle the ignition to check that the DTC did not falsely set.

2. If the vehicle is not cranking properly, the battery may be at fault. Low battery voltage can set this DTC.

#### DTC B1983 Source Battery Voltage Low

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Radio/Audio System Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check - Radio/Audio System
2 |

1. Install the scan tool.
2. Turn the ignition switch to the ON position.
3. Clear any DTCs.
4. Turn the ignition OFF.
5. Turn the ignition ON.
6. Retest for a DTC B1983.

Is the DTC still present?

--

Go to Step 3

--

3 | Is the vehicle starting/cranking properly? | -- | Go to Step 4 | Go to Step 5
4 |

1. Remove the radio and disconnect the radio connector.
2. Turn ON the ignition, with the engine OFF.
3. Measure the voltage at terminal F1 (RED).

Is the voltage measured less than the specified value?

9.5 V

Go to Step 6

Go to Step 7

5 | Test the battery and starting system. Is the repair complete? | -- | Go to Step 8 | --
6 |

1. Locate and repair the high resistance in the battery feed circuit.
2. If no problem was found with the circuit, inspect for poor connections at the radio connector.

Is the repair complete?

--

Go to Step 8

--

7 | Replace the radio. Is the replacement complete? | -- | Go to Step 8 | --
8 |

1. Install the scan tool in order to clear codes.
2. Verify that DTC B1983 is not present.

Are all DTCs cleared?

--

System OK

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