What Does B1434 Mean?
This code indicates the Body Control Module (BCM) has detected an electrical fault in the windshield wiper high/low speed relay coil circuit. The BCM monitors the relay coil for proper resistance and current flow, and has identified either an open circuit, short circuit, or excessive resistance preventing the relay from operating correctly. This affects the wiper system's ability to switch between high and low speed operation.
Common Causes
45%
Faulty wiper relay with open or shorted coil windings
30%
Damaged wiring or corroded connector between BCM and wiper relay
15%
Blown fuse or fusible link in wiper relay circuit
10%
Failed BCM relay driver circuit or internal BCM fault
Diagnostic Steps
1
Step 1: Locate the wiper high/low speed relay in the fuse/relay panel and perform visual inspection for physical damage, corrosion, or burned terminals. Check relay fuse for continuity with multimeter.
2
Step 2: Remove relay and test coil resistance across control terminals with multimeter (typically 70-120 ohms). Apply 12V directly to relay coil terminals to verify mechanical operation and listen for audible click.
3
Step 3: With relay removed, use multimeter to check for battery voltage at relay socket power terminal with ignition on. Verify ground circuit continuity at relay socket ground terminal (should be less than 1 ohm to chassis ground).
4
Step 4: Backprobe BCM connector and measure voltage on relay trigger wire while activating wipers at different speeds. Should see BCM switching between 0V and 12V to energize relay. Check wiring harness for continuity between BCM and relay socket.
5
Step 5: If all circuits test normal but code persists, perform BCM functionality test using advanced scan tool to command relay operation. Monitor current draw on relay circuit (typical 150-200mA when energized).
6
Step 6: Replace faulty component (relay, wiring, or BCM), clear codes, and cycle wipers through all speeds multiple times to verify proper operation and confirm code does not return.
Estimated Repair Cost
$75 - $400
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected an electrical fault in the windshield wiper high/low speed relay coil circuit. The BCM monitors the relay coil for proper resistance and current flow, and has identified either an open circuit, short circuit, or excessive resistance prev...
The most common cause of B1434 (Wiper Hi/Low Speed Relay Coil Circuit Failure) is: Faulty wiper relay with open or shorted coil windings
Typical repair costs for B1434 range from $75 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive in clear weather, but reduced wiper functionality may compromise visibility during rain or snow, creating a safety hazard. Repair should be completed before driving in inclement weather conditions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1434 to identify the root cause.
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Quick Info
Category
Body
System
Windshield Wiper System
Difficulty
Type
Manufacturer
Recommended Tools
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