For 1990-2009 cars

### Circuit Description

As part of its normal processing, the Integrated Radio Controller (IRC) performs a data programming check on its writes to the EEPROM. The data programming check is performed by writing to a EEPROM cell and then reading the data back. If the data matches, then no diagnostic action is taken. If the data does not match after three consecutive write and verify attempts, then the IRC sets DTC B1656.

### Conditions for Setting the DTC

DTC B1656 will set when:

• | The data read back after three consecutive write and verify attempts does not match the stored data.

• | The IRC detects an internal write malfunction.

• | The condition must occur when data is being written.

### Action Taken When the DTC Sets

• | DTC B1656 is stored in the IRC memory.

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

• | The IRC will store the value being written in another memory address in the EEPROM.

### Conditions for Clearing the DTC

DTC B1656 will clear:

• | When a successful write is required in order to change from a current DTC to a history DTC.

• | When the IRC no longer detects an internal write malfunction.

• | When the ignition key is cycled 50 times.

• | By using the scan tool.

### Diagnostic Aids

• | Since the EEPROM cannot be removed from the IRC and DTC B1656 is an internal IRC malfunction, the IRC needs to be replaced.

• | Replace the radio. Refer to Radio Replacement .