What Does B1620 Mean?
This code indicates the Body Control Module (BCM) has detected an open circuit in the rear wiper motor's low limit position sensor circuit. The low limit position sensor tells the BCM when the rear wiper blade has reached its parked or rest position at the bottom of its travel. An open circuit means there is a break in the wiring, a disconnected connector, or a failed position sensor preventing the BCM from receiving this signal.
Common Causes
35%
Damaged or corroded wiring harness between BCM and rear wiper motor assembly, often caused by water intrusion at rear hatch/liftgate
30%
Failed rear wiper motor position sensor or internal circuit board within the wiper motor assembly
25%
Loose or corroded electrical connector at rear wiper motor or BCM interface
10%
Failed Body Control Module (BCM) with internal circuit fault for wiper position input
Diagnostic Steps
1
Step 1: Perform visual inspection of rear wiper motor assembly and all associated wiring from rear hatch area to BCM location, checking for broken wires, corroded connectors, water damage, or pinched harnesses in hatch flex point
2
Step 2: Using a digital multimeter, test continuity of the low limit position sensor signal wire from the rear wiper motor connector back to the BCM connector with ignition off (should show less than 5 ohms resistance if circuit is intact)
3
Step 3: Check for proper ground and power supply at the rear wiper motor connector using multimeter with key on (typically 12V supply and solid ground reference)
4
Step 4: With motor connector disconnected, measure resistance across the position sensor terminals at the wiper motor while manually moving wiper arm through full range of motion to verify sensor functionality (resistance should change or switch states at park position)
5
Step 5: If all wiring and motor test good, inspect BCM connector terminals for corrosion or bent pins, and consider BCM internal circuit fault requiring module replacement or reprogramming
6
Step 6: After repairs, clear codes and operate rear wiper through multiple complete cycles to verify park position is detected correctly and code does not return
Estimated Repair Cost
$100 - $550
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected an open circuit in the rear wiper motor's low limit position sensor circuit. The low limit position sensor tells the BCM when the rear wiper blade has reached its parked or rest position at the bottom of its travel. An open circuit means...
The most common cause of B1620 (Wiper Rear Low Limit Input Circuit Open) is: Damaged or corroded wiring harness between BCM and rear wiper motor assembly, often caused by water intrusion at rear hatch/liftgate
Typical repair costs for B1620 range from $100 to $550, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving. The rear wiper may not park correctly or may become inoperative, reducing rear visibility in poor weather conditions but not creating an immediate safety hazard. Repair at next convenient opportunity.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1620 to identify the root cause.
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Quick Info
Category
Body
System
Body Electrical System - Rear Wiper/Washer
Difficulty
Type
Manufacturer
Recommended Tools
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