OBD-II Diagnostic Trouble Code
C0185 — Steering Wheel Position Sensor Internal
C0185 indicates an internal fault in the steering wheel position sensor. The sensor or the module reading it detected a self-test failure, meaning the sensor itself reported that its output cannot be trusted. Meaning can vary by OEM, but it usually points at the sensor rather than wiring.
Severity 3/5
Truck-relevant
Service this week
Severity
Service this week
Steering Wheel Position Sensor Internal
Code
C0185
Category
Chassis
Subsystem
Brakes
Truck-relevant
Yes
What this means for truckers
Service within a few days on a Cummins X15, Detroit DD15, PACCAR MX-13. Performance is likely degraded. Continuing to drive without service risks additional component damage.
Before you replace parts — try this first
C0185 on the Brakes system is most often failed steering angle sensor internal electronics — not a dead part. On commercial diesels especially, work these in order before spending money on parts:
- Confirm the symptoms. Match what your truck is doing to the Symptoms section below. If the code is set but the symptoms are not there, clear the code and re-test after a drive cycle — it may not return.
- Clean and dry the sensor connector. Water, road salt, or oil seeping into a connector is the #1 fake sensor failure. Disconnect, look for green corrosion or moisture, spray with electrical contact cleaner, dry, reseat. Many faults clear here for $0.
- Inspect the wiring harness. Trace the wire from the sensor toward the ECM — look for chafing against the engine block, melted insulation near the turbo or exhaust, or pinch points where a clamp has rubbed through.
- Test the sensor before swapping it. Most Common Causes (below) list the expected voltage or resistance range — a $20 multimeter saves a $300 sensor swap that does not fix the problem.
- Only then, replace the part. Use the OEM or a tier-1 aftermarket. Cheap sensors throw the same code in two weeks.
Symptoms
Stability control light on and stability control disabled, sometimes traction control off too. ABS and base brakes usually function normally. The fault may stay on even after calibration.
Common causes
- CommonFailed steering angle sensor internal electronics ($250–$800)
- OccasionalSensor lost calibration or was not initialized ($80–$200)
- OccasionalLow supply voltage during cranking upsetting the sensor ($60–$300)
- RareModule software issue ($100–$300)
How to fix
Check battery condition and charging system
When to use: Weak batteries or code set after a hard start
Try the steering angle sensor calibration procedure
When to use: Before replacing parts
Check for module software updates
When to use: Known OEM bulletin or repeat failures
Replace the sensor and calibrate
When to use: Code returns after calibration with good voltage
Affects most
No specific vehicle pattern found in our complaint database. This code can appear on any vehicle that supports OBD-II diagnostics.
Related
- → Browse all DTC trouble codes
- → Decode a VIN to check codes for your truck
- → Owner-operator maintenance guides
- → C0110 — Pump Motor Circuit Malfunction
- → C0121 — Valve Relay Circuit Malfunction
- → C0131 — ABS Pressure Sensor Circuit
- → C0161 — ABS / TCS Brake Switch Circuit
- → C0186 — Yaw Rate Sensor Bias Circuit
Frequently Asked Questions
Can I drive with code C0185?
C0185 is severity 3 — plan service within a few days. Performance is likely degraded already (you may feel reduced power, harsher shifts, or slightly worse fuel economy). Continuing to drive risks additional damage to adjacent components.
How much does it cost to fix C0185 on a commercial truck?
Total repair cost ranges $60–$800 depending on the root cause. The cheapest fix is usually the first one listed below — Failed steering angle sensor internal electronics — which is also the most common. On commercial trucks the cost is usually higher than passenger vehicles due to part availability and shop labor rates ($120–185/hour at most truck shops, vs $90–130 at general auto shops). DIY-capable fixes (sensors, hoses, filters) are at the low end; major component replacements (turbo actuator, high-pressure fuel pump, transmission solenoid pack) are at the high end. Always diagnose with a scan tool BEFORE replacing parts — guessing wrong on a $1,500 turbo actuator when the actual issue was a $30 boost hose is a common expensive mistake.
Will C0185 fail a DOT inspection?
C0185 is generally not a direct DOT inspection fail item by itself. Inspectors focus on safety-critical systems (brakes, steering, tires, lights, hours-of-service). However, the check engine light alone can trigger additional inspection scrutiny. Best practice: fix the code and clear it before a planned inspection.
What's the difference between C0185 and related codes?
C0185 is closely related to: C0110 (Pump Motor Circuit Malfunction), C0121 (Valve Relay Circuit Malfunction), C0131 (ABS Pressure Sensor Circuit), C0161 (ABS / TCS Brake Switch Circuit). These codes share the same subsystem (brakes) and often appear together. If you see this code, scan for the full code list — fixing the root cause usually clears multiple companion codes at once. If only C0185 is set without the companions, the issue is more isolated.
How do I prevent C0185 from coming back after a repair?
For C0185 (Steering Wheel Position Sensor Internal), prevention centers on the brakes system. Clean wheel speed sensors at every brake service. Inspect tone rings for cracks or rust. Keep ABS sensor harnesses away from chafe points. Don't drive through deep water that can flood the rear wheel-speed sensor connectors.