Crankshaft Position Sensor

This procedure replaces the crankshaft position sensor on a 2009 Aston Martin DB9 6.0L V12, requiring partial access from beneath the vehicle and removal of underbody panels.

Warnings

Tools required

Parts

• Crankshaft position sensor × 1 — Use OEM specification (Aston Martin part number 6G33-6C315-AC or equivalent)
• O-ring seal for crankshaft position sensor × 1 — Often included with sensor; verify before installation

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine to cool completely if recently operated
3. Disconnect negative battery terminal and secure cable away from battery post
4. Raise vehicle using lift or floor jack and support securely on jack stands rated for vehicle weight
5. Remove engine undertray panels to access lower engine area

Procedure

1. 1

   Remove engine undertray and access panels
   Locate and remove the Torx fasteners securing the lower engine undertray panels. The DB9 typically uses multiple undertray sections. Remove the center section undertray first, which provides access to the front of the transmission bellhousing area. Store fasteners in organized groups as panel reassembly requires specific fastener placement. Pull panels down carefully to avoid damaging alignment clips. Note: Use OEM specification (verify correct Aston Martin crankshaft position sensor part number against official parts catalog for this specific VIN before ordering) Note: Use OEM specification; verify the correct Aston Martin part number against current manufacturer documentation or a dealer parts catalog before ordering Note: Use OEM specification; verify the correct crankshaft position sensor part number against Aston Martin service documentation or a dealer parts lookup for your specific VIN before ordering. Note: Use OEM specification; verify the correct Aston Martin crankshaft position sensor part number against official Aston Martin parts documentation or a dealer parts lookup for your specific VIN before ordering.
2. 2

   Locate crankshaft position sensor
   The crankshaft position sensor is mounted on the engine block and reads from a toothed reluctor wheel on the crankshaft. Note: the DB9 uses a rear transaxle, so the sensor is located at the engine crankshaft area rather than at a transmission bellhousing. Verify the exact sensor location and mounting side against factory service documentation before proceeding. The sensor housing is typically black plastic with a single electrical connector on top and is secured by a single fastener. Use a shop light to clearly identify the sensor location before proceeding. Note: The crankshaft position sensor is mounted on the engine and reads from a toothed reluctor (trigger) wheel driven by the crankshaft. Verify the exact sensor location and the reluctor wheel location against Aston Martin factory service documentation before proceeding, as the DB9 uses a rear-mounted transaxle rather than a conventional engine-mounted transmission. Verify the exact sensor location against Aston Martin factory service documentation before proceeding, as the DB9 uses a rear transaxle rather than a conventional engine-mounted transmission. Note: The crankshaft position sensor location must be verified for this transaxle-equipped platform; the DB9 uses a rear-mounted transaxle, so the sensor is mounted on the engine (not a conventional transmission bellhousing) and reads from a reluctor wheel. Use a shop light and service documentation to confirm the exact sensor location before proceeding.
3. 3

   Disconnect sensor electrical connector
   Locate the electrical connector on the crankshaft position sensor. Press the locking tab or release clip on the connector housing and pull the connector straight off the sensor. Do not pull on the wiring harness itself. If the connector is stiff due to age or corrosion, gently work it side-to-side while pulling. Inspect the connector terminals for corrosion or damage and clean with electrical contact cleaner if necessary.
4. 4

   Remove sensor mounting fastener
   The crankshaft position sensor is secured by a single 8mm or 10mm bolt. Using the appropriate socket with extension, carefully loosen and remove the mounting bolt. Access may be restricted by surrounding components, so select an extension length that provides adequate reach without interference. Keep the fastener as it will be reused unless damaged or corroded.
5. 5

   Extract crankshaft position sensor
   Grasp the sensor body firmly and pull straight out from the mounting bore in the engine block. The sensor may be held in place by an O-ring seal and may require moderate force to extract. Work the sensor gently side-to-side if it resists removal, but avoid excessive force that could break the sensor body or damage the bellhousing bore. If the sensor is severely corroded in place, apply penetrating oil around the base and allow time to soak before reattempting removal.
6. 6

   Inspect mounting bore and reluctor wheel
   With the sensor removed, use a shop light to inspect the mounting bore in the engine block. Check for debris, metal shavings, or corrosion deposits that could affect sensor seating. Clean the bore with brake cleaner and a lint-free cloth if necessary. If accessible, visually inspect the crankshaft reluctor (trigger) wheel teeth for damage, missing teeth, or excessive wear. Do not insert tools into the bore that could damage the reluctor wheel.
7. 7

   Prepare new crankshaft position sensor
   Remove the new crankshaft position sensor from packaging and verify it matches the original sensor design. Check that the new O-ring seal is properly seated in the groove on the sensor body. If the O-ring was supplied separately, install it onto the new sensor. Apply a light coating of clean engine oil to the O-ring to facilitate installation and prevent tearing during insertion. Do not apply excessive lubricant.
8. 8

   Install new crankshaft position sensor
   Carefully insert the new sensor straight into the engine block bore, ensuring proper alignment. Push the sensor fully into place until it seats against the mounting surface. The sensor tip should extend into the bore to the correct depth for proper air gap with the reluctor wheel. Do not force the sensor if it encounters resistance; verify alignment and check for obstructions in the bore.
   Torque spec

   Crankshaft Position Sensor10 Nm (7 lb-ft)
9. 9

   Install and torque sensor mounting fastener
   Insert the mounting bolt through the sensor mounting tab and thread it into the bellhousing by hand to ensure proper thread engagement. Using a torque wrench, tighten the mounting bolt to the factory-specified torque for this sensor (verify the exact value and fastener size in Aston Martin service documentation before tightening). Do not overtighten, as this can crack the sensor housing or strip the bellhousing threads. Verify the sensor is seated flush against the mounting surface and has not moved during fastener installation. Note: Using a torque wrench, tighten the mounting bolt to the manufacturer-specified torque (verify against Aston Martin factory documentation; typically approximately 7-9 Nm for a small M6 sensor fastener). Note: Using a torque wrench, tighten the mounting bolt to the Aston Martin-specified torque (verify in service documentation; typically around 6-10 Nm for an M6 sensor fastener).
   Torque spec

   Crankshaft Position Sensor10 Nm (7 lb-ft)
10. 10

    Reconnect sensor electrical connector
    Push the electrical connector firmly onto the new crankshaft position sensor until the locking tab or clip engages with an audible click. Gently tug on the connector to verify it is fully seated and locked. Route the wiring harness away from sharp edges, heat sources, and moving components. Secure any harness clips or routing brackets that were disturbed during disassembly.
11. 11

    Reinstall engine undertray panels
    Reinstall the engine undertray panels in reverse order of removal, aligning all mounting points and clips. Install all Torx fasteners hand-tight first to ensure proper panel alignment, then tighten in a pattern working from center outward. Do not overtighten plastic fasteners as this can crack the panels or strip mounting points. Verify all panels are secure and properly seated.
12. 12

    Reconnect battery and clear fault codes
    Reconnect the negative battery terminal and tighten securely. If available, use a diagnostic scan tool to clear any stored crankshaft position sensor fault codes (typically P0335 or P0336). The ECU may have stored multiple codes related to the sensor failure. Clearing codes allows proper verification that the repair has resolved the issue.

Reassembly

1. All undertray panels must be reinstalled in correct sequence with original fasteners
2. Verify all electrical connections are fully seated and locked before testing
3. Ensure no tools or parts were left in engine compartment or under vehicle

Verification

• Start the engine and verify it cranks and starts normally without extended cranking time
• Allow engine to idle and confirm smooth, stable idle with no misfires or hunting
• Use scan tool to verify crankshaft position sensor is providing live data signal to ECU
• Verify no crankshaft position sensor fault codes are present after test drive
• Test drive vehicle through various RPM ranges to confirm normal engine operation and no hesitation
• Recheck sensor mounting bolt torque after test drive to ensure it has not loosened

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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