VAPS II Steering Assist Open Circuit
The C1898 code indicates that the control module has detected an open circuit in the Variable Assist Power Steering (VAPS II) system loop. This system, used in certain vehicles, electronically adjusts steering assist based on vehicle speed and other operating conditions. An open circuit disrupts communication or control of the actuator or sensor, potentially causing the system to enter a fail-safe mode with fixed assist or disabling the variable assist function, affecting maneuverability.
1. Commonly Affected Makes
2. Most Common Causes
- Open, shorted, or damaged wiring in the VAPS II circuit
- Corroded, disconnected, or oxidized terminals at the actuator or VAPS II module connector
- Faulty steering assist control valve actuator with open winding
- Internal failure of the VAPS II control module
- Missing or erratic vehicle speed sensor (VSS) signal affecting the control loop
- Poor ground connection in the power steering system
3. Symptoms You Will Notice
- Steering feels heavy or inconsistent, especially at low speeds
- Variable assist function not working; steering assist may be fixed or reduced
4. Step-by-Step Diagnosis
Scan for additional codes and check VSS signal
Inspect VAPS II wiring and connectors for damage, corrosion, or loose connections
Test actuator resistance and compare to specifications
Check ground connections and power supply to VAPS II module
If wiring and actuator are OK, suspect faulty VAPS II module
5. Frequently Asked Questions
Is it safe to drive?▼
Driving is possible but not recommended for long distances. The steering may become heavy or unpredictable, increasing the risk of an accident. Have the system repaired promptly.
How much does it cost to fix?▼
Repair costs range from $100 to $600 depending on the cause. Simple wiring repairs may cost $100-$200, while replacing the VAPS II module or actuator can run $300-$600.