What Does B1623 Mean?
DTC B1623 indicates the Body Control Module (BCM) has detected a fault in the output circuit that controls the keypad illumination lamp. This is a manufacturer-specific code related to the keyless entry or door keypad lighting system. The BCM has determined that the circuit is either open, shorted to ground, shorted to power, or the lamp itself has failed, preventing proper illumination of the entry keypad.
Common Causes
35%
Failed keypad illumination bulb or LED assembly
30%
Open or damaged wiring between BCM and keypad lamp
20%
Corroded or loose connector at keypad assembly
10%
Short to ground in lamp circuit wiring
5%
Failed BCM output driver circuit
Diagnostic Steps
1
Step 1: Visually inspect the keypad assembly exterior lamp/LED for obvious damage, moisture intrusion, or burnt components. Check for proper physical installation of the keypad unit.
2
Step 2: Locate and disconnect the keypad assembly electrical connector. Inspect connector terminals for corrosion, bent pins, or damage. Clean terminals with electrical contact cleaner if needed.
3
Step 3: Using a multimeter, check for voltage at the keypad connector harness side when the system should be illuminated (typically when doors are unlocked or opened). Should read battery voltage (11-14V) on the power supply wire.
4
Step 4: With ignition off, measure resistance of the lamp circuit from the connector to ground. Compare reading to manufacturer specifications (typically 2-10 ohms for bulb, higher for LED). Infinite resistance indicates open circuit; zero ohms indicates short to ground.
5
Step 5: If circuit tests good, reconnect keypad and command lamp on using scan tool active tests or BCM output control. If lamp still doesn't illuminate, replace keypad assembly.
6
Step 6: After repair, clear codes and verify lamp operation through multiple door lock/unlock cycles. Confirm code does not return and lamp functions properly under all conditions.
Estimated Repair Cost
$75 - $350
Parts + labor, varies by vehicle and location
DTC B1623 indicates the Body Control Module (BCM) has detected a fault in the output circuit that controls the keypad illumination lamp. This is a manufacturer-specific code related to the keyless entry or door keypad lighting system. The BCM has determined that the circuit is either open, shorted t...
The most common cause of B1623 (Lamp Keypad Output Circuit Failure) is: Failed keypad illumination bulb or LED assembly
Typical repair costs for B1623 range from $75 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving. This is a convenience feature failure that only affects keypad illumination for nighttime entry. No safety risk, but should be repaired for full functionality of security and entry systems.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1623 to identify the root cause.
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Quick Info
Category
Body
System
Body Control/Keyless Entry System
Difficulty
Type
Manufacturer
Recommended Tools
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