What Does B1521 Mean?
B1521 indicates the Body Control Module (BCM) has detected an electrical fault in the Driver Information Center (DIC) switch circuit. This code is triggered when the BCM receives an abnormal voltage signal from the DIC control switches, which may be open, shorted to ground, shorted to voltage, or experiencing high resistance. The DIC switch allows the driver to navigate menus and display information on the instrument cluster or information center.
Common Causes
45%
Faulty DIC switch assembly with internal short circuit or open circuit
30%
Damaged or corroded wiring harness between BCM and DIC switch, including chafed wires or poor connections
15%
Loose or corroded electrical connector at DIC switch or BCM interface
10%
Faulty Body Control Module with internal circuit failure
Diagnostic Steps
1
Step 1: Perform visual inspection of DIC switch assembly for physical damage, worn buttons, or signs of liquid intrusion. Check all connectors at the DIC switch and BCM for corrosion, bent pins, or looseness.
2
Step 2: With ignition on and using a digital multimeter, backprobe the DIC switch connector to measure voltage at the power supply pin (typically should read battery voltage or 5V reference depending on design) and ground circuit (should read 0V).
3
Step 3: Using multimeter in resistance mode with ignition off and DIC switch disconnected, test the switch by measuring resistance across switch terminals while actuating each button. Compare readings to manufacturer specifications (typically open circuit when not pressed, low resistance when pressed).
4
Step 4: Inspect wiring harness from DIC switch to BCM for chafing, pinching, or damage, particularly at flex points near steering column. Perform continuity test on all circuit wires with switch disconnected.
5
Step 5: If all circuits test normal, connect a known-good DIC switch or perform voltage monitoring at BCM connector while actuating switches to isolate if fault is in switch assembly or BCM input circuits.
6
Step 6: Clear code and perform operational test of DIC functions. Monitor live data on scan tool to verify proper signal transmission from DIC switches to BCM during button presses.
Estimated Repair Cost
$150 - $450
Parts + labor, varies by vehicle and location
B1521 indicates the Body Control Module (BCM) has detected an electrical fault in the Driver Information Center (DIC) switch circuit. This code is triggered when the BCM receives an abnormal voltage signal from the DIC control switches, which may be open, shorted to ground, shorted to voltage, or ex...
The most common cause of B1521 (Driver Information Center (DIC) Switch Circuit) is: Faulty DIC switch assembly with internal short circuit or open circuit
Typical repair costs for B1521 range from $150 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving as this code does not affect vehicle operation or safety systems. The DIC switch functionality may be impaired, preventing menu navigation or display changes, but primary vehicle functions remain operational. Repair can be scheduled at convenience.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1521 to identify the root cause.
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Quick Info
Category
Body
System
Body Control and Driver Information Display System
Difficulty
Type
Manufacturer
Recommended Tools
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