What Does B1890 Mean?
This diagnostic trouble code indicates that the Body Control Module (BCM) has detected an abnormal voltage condition in the PAD (Park Assist Distance or Parking Assist Display) warning lamp circuit. Specifically, the circuit is shorted to battery voltage, meaning the lamp circuit is receiving constant power when it should be controlled by the BCM. This prevents proper operation of the warning lamp and may cause it to illuminate continuously or behave erratically.
Common Causes
45%
Damaged wiring harness or chafed wire causing short to battery voltage in the warning lamp circuit
25%
Faulty BCM internal driver circuit or output transistor stuck closed
20%
Corroded or damaged connector pins at the warning lamp or BCM creating cross-circuit short
10%
Failed PAD warning lamp assembly with internal short to power
Diagnostic Steps
1
Step 1: Perform visual inspection of the PAD warning lamp wiring harness from BCM to lamp, looking for chafed insulation, pinched wires, or damage near sharp edges or moving components. Check all connectors for corrosion, bent pins, or moisture intrusion.
2
Step 2: Disconnect the PAD warning lamp connector and measure voltage at the lamp side connector terminal with ignition on. Should read 0V; if battery voltage is present, trace wiring from lamp back toward BCM to locate short to power source.
3
Step 3: With lamp disconnected, measure resistance between the BCM control wire and battery positive at the lamp connector. Should read infinite resistance (open circuit); low resistance indicates short to power in harness requiring repair or replacement.
4
Step 4: If wiring tests normal, reconnect lamp and disconnect BCM connector. Measure voltage on the lamp control circuit at BCM side with ignition on. Battery voltage present indicates short between BCM and lamp; no voltage suggests faulty BCM output driver.
5
Step 5: If BCM is suspected, verify proper BCM ground circuits and power supply voltages are within specification. Test BCM output with new or known-good lamp assembly to confirm internal BCM failure.
6
Step 6: After repair, clear codes, cycle ignition, and operate parking assist system through full range. Monitor for code return and verify warning lamp operates correctly during system activation.
Estimated Repair Cost
$100 - $650
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 PAD (Park Assist Distance or Parking Assist Display) warning lamp circuit. Specifically, the circuit is shorted to battery voltage, meaning the lamp circuit is receiving consta...
The most common cause of B1890 (PAD Warning Lamp Circuit Short to Battery) is: Damaged wiring harness or chafed wire causing short to battery voltage in the warning lamp circuit
Typical repair costs for B1890 range from $100 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This code does not affect vehicle safety or drivability, but may prevent proper warning lamp function for the parking assist system, potentially leading to operator unawareness of system malfunctions. Repair can be scheduled at convenience but should be addressed to maintain full parking assist functionality.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1890 to identify the root cause.
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Quick Info
Category
Body
System
Parking Assist System / Body Control
Difficulty
Type
Manufacturer
Recommended Tools
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