What Does B1983 Mean?
This diagnostic trouble code indicates that the Body Control Module (BCM) has detected an abnormal voltage condition in the driver's door unlock relay circuit. Specifically, the circuit is showing a direct connection to battery voltage when it should not be energized, suggesting a short-to-power condition. This prevents the BCM from properly controlling the driver's door lock/unlock function and may cause unintended door unlocking or relay damage.
Common Causes
45%
Damaged wiring harness or chafed insulation in door jamb area causing short to power wire
30%
Failed driver's door lock relay with internal short to battery circuit
15%
Corroded or damaged connector terminals at BCM or relay socket allowing cross-circuit contact
10%
Failed Body Control Module with internal driver circuit fault
Diagnostic Steps
1
Step 1: Perform visual inspection of driver's door wiring harness in the door jamb area and along the door frame. Look for chafed, pinched, or damaged insulation that could be contacting battery voltage circuits. Flex the harness while monitoring the code status.
2
Step 2: Locate and remove the driver's door unlock relay from its socket. Using a digital multimeter, check for battery voltage (12V+) on the relay control circuit terminal at the relay socket with ignition on. There should be no voltage present when relay is commanded off.
3
Step 3: If battery voltage is present at the relay socket control terminal, disconnect the BCM connector and retest. If voltage disappears, BCM has internal short. If voltage persists, trace the control wire from BCM to relay for short to power wire using resistance and continuity tests.
4
Step 4: If no short is found in wiring, reconnect BCM and install a known-good relay. Command the door unlock function using the scan tool actuation test. Monitor current draw and voltage levels. Replace relay if it draws excessive current or shows internal short.
5
Step 5: Clear codes and cycle the door lock/unlock function multiple times using both key fob and interior switch. Verify proper operation and confirm no codes return. Check for proper voltage drop across relay coil during activation.
Estimated Repair Cost
$100 - $450
Parts + labor, varies by vehicle and location
This diagnostic trouble code indicates that the Body Control Module (BCM) has detected an abnormal voltage condition in the driver's door unlock relay circuit. Specifically, the circuit is showing a direct connection to battery voltage when it should not be energized, suggesting a short-to-power con...
The most common cause of B1983 (Driver's Door Unlock Relay Circuit Short to Battery) is: Damaged wiring harness or chafed insulation in door jamb area causing short to power wire
Typical repair costs for B1983 range from $100 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This code does not present a direct safety hazard and the vehicle is safe to drive. The primary concern is potential for unintended door unlocking which could present a security risk, and there is minor risk of relay or BCM damage if the short persists.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1983 to identify the root cause.
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Quick Info
Category
Body
System
Body Control and Convenience Systems
Difficulty
Type
Manufacturer
Recommended Tools
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