What Does B1622 Mean?
This code indicates the Body Control Module (BCM) has detected a short to ground condition in the rear wiper motor's low limit input circuit. The low limit circuit monitors the wiper blade position to ensure it parks correctly at the bottom of its travel range. The BCM detected abnormally low voltage on this signal wire, indicating current is flowing directly to ground instead of through the position sensor.
Common Causes
45%
Damaged or chafed wiring harness causing the low limit sensor wire to contact ground, typically near rear hatch hinges or through rear door boot
30%
Failed rear wiper motor with internal short to ground in the position sensor circuit or park switch contacts
15%
Corroded or water-damaged connector at rear wiper motor or BCM causing short path to ground
10%
Faulty Body Control Module with internal circuit failure on the low limit input channel
Diagnostic Steps
1
Step 1: Perform visual inspection of rear wiper motor and harness, checking for obvious damage, water intrusion, corroded connectors, or chafed wiring particularly at flex points near rear hatch hinges
2
Step 2: Disconnect rear wiper motor connector and use a digital multimeter to measure resistance between the low limit signal wire (consult wiring diagram for pin identification) and ground with ignition off. Reading should be greater than 10k ohms; less than 5 ohms confirms short to ground in harness or motor
3
Step 3: If harness tests good at motor connector, backprobe the BCM connector low limit input pin and measure voltage with ignition on and motor disconnected. Should read 5V or 12V reference voltage depending on system design. No voltage or ground reading indicates BCM-side harness fault
4
Step 4: If harness integrity is confirmed, reconnect motor and monitor low limit circuit voltage while manually cycling wiper through full range. Voltage should vary smoothly; instant drop to zero indicates internal motor short
5
Step 5: Repair identified wiring damage with proper splice and heat shrink, or replace faulty rear wiper motor assembly. Clear codes and cycle rear wiper through multiple operations to verify proper park function and confirm no code return
Estimated Repair Cost
$120 - $450
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected a short to ground condition in the rear wiper motor's low limit input circuit. The low limit circuit monitors the wiper blade position to ensure it parks correctly at the bottom of its travel range. The BCM detected abnormally low voltag...
The most common cause of B1622 (Wiper Rear Low Limit Input Circuit Short To Ground) is: Damaged or chafed wiring harness causing the low limit sensor wire to contact ground, typically near rear hatch hinges or through rear door boot
Typical repair costs for B1622 range from $120 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This fault does not affect vehicle safety or drivability and the vehicle is safe to operate. Rear wiper may not function properly or may not park correctly, reducing rear visibility in inclement weather.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1622 to identify the root cause.
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Quick Info
Category
Body
System
Body Controls - Rear Wiper System
Difficulty
Type
Manufacturer
Recommended Tools
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