C1124 Code: Meaning, Symptoms, Causes & Fix

Overview

Code C1124 indicates a fault in Input shaft speed signal missing/faulted, typically within ABS/chassis dynamics and brake control.

Symptoms

longer braking intervention
ABS/traction light on
chassis warning indicator

Common causes

Component failure in the monitored system affecting input shaft speed signal missing/faulted
Electrical fault in the affected circuit
Connector pin damage/corrosion or harness stress near related components

How to diagnose C1124

Confirm C1124 and capture freeze-frame data with a professional scan tool.
Inspect wiring, connectors, and grounds related to input shaft speed signal missing/faulted for obvious defects.
Use freeze-frame and live data to isolate whether the issue is electrical, mechanical, or control logic.
Check for related DTCs to identify the root-cause chain before replacing parts.
After repair, clear codes and confirm readiness monitors complete without recurrence.

Severity of code C1124

Low: This code is low to moderate severity in most cases, but diagnosis is still recommended to avoid recurring warnings.

Can you drive with C1124?

The vehicle is often drivable with C1124, but plan a repair window to prevent repeat faults.

If the warning lamp is flashing or drivability/safety is affected, avoid driving and diagnose immediately.

How to fix it (step-by-step)

Repair obvious wiring/connector faults first to prevent repeat parts replacement.
Address the root fault mode (generic) in the input shaft speed signal missing/faulted circuit/system.
Apply the required relearn/adaptation procedure if specified by service information.
Road-test and verify C1124 remains cleared under the conditions that originally set the code.

Fix options

Clear code and confirm through drive cycle.
Inspect circuit and connector condition.
Clear DTCs and verify with live data and completed drive cycle.

Typical repair cost

$120-$500

Common mistakes when diagnosing C1124

Replacing parts without verifying voltage, ground, and signal integrity first.
Ignoring related stored/pending codes that indicate upstream faults.
Skipping post-repair verification drive cycle and readiness checks.

C1124 in common vehicles

C1124 appears across makes such as Nissan, Hyundai, Kia, Volkswagen. Failure patterns differ by platform: wiring routes, software calibration, and component supplier revisions can change root cause.

Frequently asked questions

What causes C1124?

C1124 is commonly set by generic faults affecting input shaft speed signal missing/faulted.

How much does it cost to fix C1124?

For C1124, repair costs are typically $120-$500 depending on exact root cause, labor rates, and part quality.

Can I clear C1124 without repair?

You can clear C1124 temporarily, but the code usually returns until the underlying fault is corrected.