C1899

What Does Code C1899 Mean?

Diagnostic Trouble Code (DTC) C1899 indicates a specific electrical fault within the Vehicle Speed Sensitive Power Steering (VAPS II) system circuit, specifically identified as a “Steering VAPS II Circuit Loop Short To Battery.” The VAPS II system, commonly utilized in Ford and Lincoln vehicles, is an electronically controlled hydraulic power steering system designed to dynamically adjust steering assist based on vehicle speed. This ensures optimal steering feel, providing maximum assist for effortless maneuvering at low speeds and reduced assist at higher speeds for enhanced road feel and stability.

The Power Steering Control Module (PSCM), or a dedicated steering module, continuously monitors the voltage signals within the VAPS II control circuit. When C1899 is logged, it signifies that the control module has detected an abnormally high voltage level on one of the VAPS II circuit wires—a voltage consistent with a direct connection to the vehicle’s battery positive terminal or a constantly supplied 12-volt circuit. This “short to battery” condition disrupts the module’s ability to accurately send control signals or interpret feedback from the VAPS II solenoid or actuator. The module perceives this excessive voltage as an out-of-range input, compromising the proper operation and variable assist function of the power steering system. This fault prevents the module from modulating hydraulic pressure correctly, directly impacting steering responsiveness and driver effort.

Common Symptoms

• Inconsistent or Erratic Steering Effort: Drivers may experience the steering wheel feeling unexpectedly heavy at low speeds or excessively light and “floaty” at higher speeds, indicating a failure of the variable assist function.
• Illuminated Warning Lights: The “Service Engine Soon,” “Power Steering,” or a specific chassis system warning light (e.g., related to steering or stability control) may illuminate on the instrument cluster.
• Reduced or Complete Loss of Power Steering Assist: In some cases, the VAPS II system may revert to a minimal assist mode, making the steering wheel significantly harder to turn, especially during low-speed maneuvers or parking.
• No Change in Steering Feel with Vehicle Speed: The noticeable difference in steering resistance that typically occurs with changes in vehicle speed will be absent, confirming the VAPS II system is not functioning.
• Audible Noise from Steering Gear: While less common, electrical faults can sometimes cause unusual clicking or buzzing sounds from the steering gear area, though this is typically more associated with mechanical or hydraulic issues.

What Causes the Code C1899?

• Damaged Wiring Harness: The most frequent cause involves physical damage to the VAPS II wiring harness, such as chafing, pinching, or severing, which allows a control or signal wire to come into direct contact with a fused 12V constant power source or an ignition-switched 12V supply.
• Faulty VAPS II Solenoid/Actuator: An internal electrical short within the VAPS II solenoid or actuator itself can cause one of its internal power feeds to short directly to the signal circuit, presenting a “short to battery” condition to the control module.
• Corroded or Damaged Electrical Connectors: Corrosion, bent pins, or foreign debris within the multi-pin electrical connectors for the VAPS II solenoid, the Power Steering Control Module (PSCM), or intermediate harness connectors can create an unintended bridge between a signal wire and a power supply pin.
• Internal Power Steering Control Module (PSCM) Malfunction: Although less common, an internal failure within the PSCM (or relevant control module) where a driver circuit or internal trace shorts a VAPS II signal line to the module’s internal 12V power supply.
• Incorrect Aftermarket Component Installation or Wiring: Poorly installed aftermarket accessories, stereo systems, or modifications that inadvertently tap into or cross-connect with the VAPS II circuit, creating a short to a constant power source.

How to Diagnose and Troubleshoot

Diagnosing C1899 requires methodical electrical testing to pinpoint the exact location of the short-to-battery condition.

1. Initial Scan and Visual Inspection:
   • Connect an OBD-II scan tool and retrieve all current, pending, and history DTCs, along with freeze frame data. Note any associated codes related to the power steering, ABS, or network communication.
   • Clear the C1899 code and perform a short test drive to see if the code immediately resets. This helps determine if the fault is hard (constant) or intermittent.
   • Perform a thorough visual inspection of the entire VAPS II wiring harness, from the Power Steering Control Module (PSCM) to the VAPS II solenoid located on the steering gear. Look for any obvious signs of physical damage such as chafing against engine components, exhaust, or frame, cuts, pinches, or signs of heat damage.
   • Carefully inspect all electrical connectors involved in the VAPS II circuit for corrosion, bent pins, pushed-back terminals, or loose connections. Disconnect, inspect, clean, and securely reconnect them.
2. Verify VAPS II Circuit for Short to Battery:
   • Locate and disconnect the electrical connector at the VAPS II solenoid on the steering gear.
   • With the ignition in the OFF position, use a Digital Multimeter (DMM) set to Volts DC. Connect the negative DMM lead to a known good chassis ground point.
   • Carefully probe each pin within the VAPS II harness connector (vehicle side, not the solenoid itself). You should see approximately 0V on all signal and ground wires.
   • Turn the ignition to the ON position (engine OFF). Repeat probing each pin. An unexpected reading of approximately 12V (battery voltage) on a circuit that should be a signal, signal return, or ground identifies the wire with the “short to battery.”
3. Isolate the Shorted Wire:
   • Once the specific wire exhibiting the short-to-battery condition is identified, disconnect the harness connector at the Power Steering Control Module (PSCM) or the relevant steering module.
   • With both ends of the suspect wire now disconnected (at the VAPS II solenoid and the PSCM), use the DMM set to Ohms or Continuity mode.
   • Place one DMM lead on the suspect wire’s terminal at either the VAPS II solenoid harness connector or the PSCM harness connector. Place the other DMM lead on the vehicle’s positive battery terminal (or a known constant 12V source). A low resistance reading (typically less than 100 Ohms, or indicating continuity) confirms a direct short to the battery along that wire run.
   • To pinpoint the exact location of the short, carefully trace the path of the identified wire, visually inspecting it more thoroughly. Gently flex and manipulate the harness in suspicious areas while monitoring the DMM for intermittent continuity if the code was intermittent.
4. Test VAPS II Solenoid for Internal Short:
   • If the wiring harness itself checks out with no external shorts, the internal VAPS II solenoid may be at fault.
   • With the solenoid completely disconnected, use the DMM to measure resistance across the solenoid’s terminals. Compare readings to factory specifications (typically found in a service manual). An open circuit or a very low resistance value (near zero) between a signal terminal and its internal power feed, or between a terminal and the solenoid’s metal housing, indicates an internal short.
5. Verify Power Steering Control Module (PSCM) Integrity:
   • If all wiring and solenoid checks are conclusive and point away from these components, then investigate the PSCM. Check for proper power and ground inputs to the PSCM itself according to wiring diagrams.
   • If all external circuits are confirmed good, an internal fault within the PSCM (e.g., a shorted driver circuit) may be present. This typically necessitates replacement and often requires specialized programming or calibration with a factory-level scan tool.

Recommended Repairs and Solutions

Addressing the C1899 code primarily involves repairing or replacing the component identified as having the “short to battery.”

• Repair or Replace Damaged Wiring: If the diagnostic process reveals a damaged section of the wiring harness, the compromised wire(s) must be professionally repaired. This involves cutting out the damaged section, soldering in a new piece of wire of the correct gauge, and insulating the repair with heat-shrink tubing. For extensive damage or difficult-to-access areas, replacing the entire harness section may be more practical. Always ensure repairs are robust and properly insulated.
• Replace Faulty VAPS II Solenoid/Actuator: If an internal short within the VAPS II solenoid is confirmed, the solenoid must be replaced. This procedure often requires specialized tools and may involve removing parts of the steering gear assembly. After replacement, the power steering system must be thoroughly bled of air to ensure proper function and prevent pump damage.
• Repair or Replace Corroded/Damaged Connectors: If corrosion, bent pins, or poor terminal contact in an electrical connector is the root cause, the connector should be cleaned with specialized electrical contact cleaner, or the entire connector body and terminals replaced. Ensure all pins are straight and make secure, positive contact.
• Replace Power Steering Control Module (PSCM): Should all other potential causes be ruled out, and proper power/ground supplies to the module be verified, a faulty PSCM may be the culprit. PSCM replacement typically requires programming or calibration using a factory or equivalent diagnostic scan tool to integrate the new module with the vehicle’s network and ensure correct operation.

Mechanic’s Tips:

• Always disconnect the vehicle’s battery terminals before performing any electrical diagnostic or repair work to prevent accidental shorts, module damage, or personal injury.
• After replacing any power steering component, it is absolutely critical to perform a proper power steering system bleed procedure to remove all trapped air. Failure to do so can result in noisy operation, inconsistent steering assist, and premature failure of the power steering pump.
• Some VAPS II systems may require a specific relearn or calibration procedure after component replacement, particularly after replacing the PSCM. Always consult the vehicle’s factory service manual for exact specifications and procedures.
• When inspecting wiring, pay close attention to high-stress areas where harnesses might be bent sharply, exposed to heat, or pass through metal bulkheads or clips, as these are common points for chafing and shorts.
• Use dielectric grease on electrical connectors after cleaning or repair to prevent future corrosion and ensure a robust connection.