Automatic Headlamp Leveling Control Module Rear Axle Sensor Signal
Table of contents
B3420 CADILLAC Possible Causes
- Faulty Headlamp Leveling Control Module Rear Axle Sensor
- Headlamp Leveling Control Module Rear Axle Sensor harness is open or shorted
- Headlamp Leveling Control Module Rear Axle Sensor circuit poor electrical connection
- Faulty Headlamp Leveling Control Module
How do I fix code B3420 CADILLAC?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Tech Notes
- B3420 02: Automatic Headlamp Leveling Control Module Rear Axle Sensor Signal Circuit Short to Ground
- B3420 05: Automatic Headlamp Leveling Control Module Rear Axle Sensor Signal Circuit High Voltage/Open
- B3420 08: Automatic Headlamp Leveling Control Module Rear Axle Sensor Signal Circuit Performance – Signal Invalid
Cost of diagnosing the B3420 CADILLAC code
The cost of diagnosing the B3420 CADILLAC code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
B3420 CADILLAC Description
The front and rear suspension position sensors provide the headlamp control module with front and rear suspension position information. Each sensor receives a 5 V reference, signal, and low reference circuits from the headlamp control module. The sensors are connected to the control arms at the front and rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arms. This causes the signal output of the sensors to change. The headlamp control module compares the information from the front and rear suspension position sensors and adjusts the headlamp leveling as needed. The Diagnostic Trouble Code (DTC) will set when the headlamp control module detects no signal and low voltage on the sensor signal line.