What causes C1850 on a Honda?

Faulty AWD fail safe relay Fail safe relay harness is open or shorted Fail safe relay circuit poor electrical connection Faulty AWD control unit Low battery voltage affecting the AWD system

How do I fix C1850 on a Honda?

Confirm the code with a scan tool and check the AWD warning light Inspect the relay and its connector for corrosion, moisture, and loose pins Test the relay coil and contacts and the wiring to the AWD control unit Check battery voltage and charging before replacing parts Replace the fail safe relay if it fails testing, then clear codes and retest

C1850 The AWD control unit saw the fail safe relay stuck

Q: What does C1850 mean on a Honda?

C1850. The AWD control unit saw the fail safe relay stuck. The all wheel drive system may drop out and the warning light can come on. Applies to Honda and Acura models that use this code.

Category: Chassis
Severity: Chassis Warning Light
Applies to: Honda and Acura models that use this code

What does C1850 mean on a Honda?

C1850. The AWD control unit saw the fail safe relay stuck. The all wheel drive system may drop out and the warning light can come on. This Honda-enhanced code applies to Honda and Acura models that use this code.

Common causes of C1850

Faulty AWD fail safe relay
Fail safe relay harness is open or shorted
Fail safe relay circuit poor electrical connection
Faulty AWD control unit
Low battery voltage affecting the AWD system

How to fix C1850

Confirm the code with a scan tool and check the AWD warning light
Inspect the relay and its connector for corrosion, moisture, and loose pins
Test the relay coil and contacts and the wiring to the AWD control unit
Check battery voltage and charging before replacing parts
Replace the fail safe relay if it fails testing, then clear codes and retest

Sources and review

Last updated 2026-09-29.