Steering Angle Sensor

This procedure removes and replaces the steering angle sensor on a 2009 Aston Martin DB9, which measures steering wheel position for the stability control and active suspension systems.

Warnings

Tools required

Parts

• Steering angle sensor × 1 — Use OEM specification
• Steering column trim panel clips (if damaged) × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground with wheels pointed straight ahead. Mark the steering wheel position at 12 o'clock with tape for reference.
2. Engage parking brake and place transmission in Park.
3. Disconnect battery negative terminal using 10mm socket. Wait minimum 15 minutes before proceeding.
4. Adjust steering column to its lowest and most extended position for maximum access to lower trim panels.
5. Ensure diagnostic scanner is available and functional before beginning disassembly, as calibration must be performed immediately after installation.

Procedure

1. 1

   Remove lower steering column trim panels
   Locate the lower steering column cover assembly beneath the steering wheel. Insert trim tool at the rear seam of the lower panel and carefully release the retaining clips working from rear to front. The lower panel may be a single piece or separate into halves on this platform; verify configuration against factory documentation. Release the retaining clips evenly and remove the lower panel(s) by pulling rearward and down. Set panels aside with interior surfaces facing up to prevent scratching.
2. 2

   Disconnect steering column electrical connectors
   Identify the multi-pin harness connector bundle on the left side of the steering column shaft. Press the locking tab on each connector and pull straight away from the column. There are typically multiple connectors in this location serving the clockspring, column switches, and (if separate) the steering angle sensor; note that on some configurations the steering angle sensor is integrated with the clockspring assembly. Leave connectors hanging without strain on the wiring.
3. 3

   Remove upper steering column shroud
   The upper column shroud (surrounding the ignition key area) is secured by Torx fasteners accessible from underneath (confirm exact count against factory documentation). Remove these fasteners using T25 Torx driver. Tilt the shroud upward at the front and lift away from the column. On some DB9 units, the shroud may have a tab at the rear that requires sliding forward slightly before lifting. Note: The upper column shroud (surrounding the ignition key area) is secured by Torx fasteners accessible from underneath; verify the exact count and size against factory documentation.
4. 4

   Access steering angle sensor mounting
   The steering angle sensor on this platform may be integrated into the clockspring/rotary coupler assembly or mounted as a separate ring on the lower steering column shaft just below the clockspring. Confirm against factory documentation whether the sensor is a standalone serviceable part. When separate, it appears as a gray or black plastic ring assembly that wraps around the shaft with an electrical connector extending from it. Visually confirm the sensor position and verify the connector was disconnected in the previous step.
5. 5

   Remove steering angle sensor fasteners
   The sensor retention method and fastener count must be verified against factory documentation for this platform; it may use Torx fasteners or integral clips. If Torx fasteners are used, confirm the exact size before removal. Remove both fasteners completely, noting their length for reinstallation. Support the sensor with one hand as you remove the second fastener to prevent it from falling. Note: Confirm the exact Torx size against factory documentation before removal (commonly T20 or T25). Note: The sensor retention method and fastener count must be verified against factory documentation for this platform; it may use Torx fasteners or integral clips. If Torx fasteners are used, confirm the exact size and count before removal. Remove all fasteners completely, noting their length for reinstallation.
6. 6

   Remove steering angle sensor from column
   With fasteners removed, carefully separate the sensor housing halves if the design is split-collar type, or slide the complete sensor assembly downward off the column shaft. The sensor may be a split-collar clamshell design or integrated with the clockspring assembly; verify the configuration against factory documentation before attempting removal. Note the orientation of the sensor relative to the steering shaft and any alignment marks or notches. Do not rotate the internal sensor gear if visible. Note: Verify against factory documentation whether this sensor is a split-collar (clamshell) design or a one-piece ring that slides off the shaft, and proceed accordingly. Note: Depending on the specific sensor design, the unit may be a split-collar type that opens like a clamshell, or a one-piece ring that slides downward off the shaft; verify the design against factory documentation before removal.
7. 7

   Prepare new steering angle sensor
   Remove the new sensor from packaging. Verify it matches the removed unit in connector type and mounting hole positions. If the new sensor has a transport lock or locking pin (common on replacement units), do not remove it yet. Inspect the steering column shaft contact area and clean any dirt or debris using a lint-free cloth.
8. 8

   Install new steering angle sensor
   Position the new sensor around the steering column shaft, ensuring any alignment notch or flat on the shaft engages with the corresponding feature inside the sensor housing. If split-collar type, close both halves around the shaft. Align the mounting holes with the threaded inserts in the column. Install both Torx fasteners finger-tight initially, then torque to the factory-specified value (verify against factory documentation; do not assume). Do not overtighten as the plastic housing can crack. Note: Install both Torx fasteners finger-tight initially, then torque evenly to the factory-specified value (confirm specification against factory documentation).
9. 9

   Remove sensor transport lock if present
   If the new sensor has a yellow or orange transport locking pin or tab, carefully remove it now according to the manufacturer's instructions (typically pull straight out or twist and remove). Verify the sensor internal mechanism moves freely by very gently rocking the steering wheel 1-2 degrees in each direction while observing the sensor.
10. 10

    Reconnect electrical connectors
    Locate the steering angle sensor connector and push it firmly onto the sensor until you hear or feel a positive click. Reconnect the remaining column connectors (clockspring and switches) to their respective positions. Verify all connector locks are fully engaged and no pins are visible.
11. 11

    Reinstall steering column trim panels
    Position the upper column shroud over the column, engaging any rear retention tabs first, then pressing down at the front. Install the Torx fasteners and tighten securely but do not overtighten plastic threads. Install the lower column trim panels by aligning the clips and pressing firmly until each clip audibly seats. Check that all panel gaps are even and no clips remain unengaged.
12. 12

    Reconnect battery and perform sensor calibration
    Reconnect the battery negative terminal and tighten to secure. Connect the factory Aston Martin diagnostic tool (verify exact tool designation against factory documentation; the DB9 VH platform uses Ford/Jaguar-derived diagnostics) to the OBD-II port. Navigate to the ABS/DSC (stability control) module. Select steering angle sensor calibration or initialization function. Follow the on-screen prompts, which typically require confirming wheels are straight ahead, ignition on/engine off, and then executing the calibration routine. The scanner will command the sensor to learn the center position. This process takes 30-60 seconds. Verify calibration completion with no fault codes present. Note: which measures steering wheel position for the dynamic stability control (DSC) system. Note: which measures steering wheel position for the DSC/stability control system. Note: which measures steering wheel position for the DSC (Dynamic Stability Control) system.

Reassembly

1. Ensure all steering column trim panels are fully seated with no rattles or loose clips before road testing.
2. Verify the steering wheel returns to the marked 12 o'clock position when wheels are straight ahead.
3. All electrical connectors must be fully locked to prevent intermittent faults.

Verification

• With ignition on and engine running, verify the stability control warning light (ESP) is not illuminated on the instrument cluster.
• Using the diagnostic scanner, read the steering angle sensor data stream and verify it shows approximately 0 degrees with wheels straight ahead, and changes smoothly as the wheel is turned in both directions.
• Perform a low-speed test drive and verify the stability control system does not activate unexpectedly during gentle turns.
• Check for any stored fault codes related to steering angle sensor communication or plausibility.
• Verify the active suspension system (if equipped) responds normally to steering inputs without warning messages.

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