Replace the input speed sensor on the electric drive unit (EDU) transmission of the 2023 Chevrolet Bolt EUV, requiring partial EDU access and fluid handling.

Warnings

Tools required

Parts

• Transmission input speed sensor × 1 — Use OEM GM part number
• Sensor O-ring seal × 1 — Usually included with sensor
• Transmission drain plug crush washer × 1 — GM 24236928 or equivalent
• EDU cover gasket × 1 — Use OEM specification

Fluids

• ACDelco Dexron VI ATF — 2 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect 12V negative battery cable and wait 2 minutes for system capacitors to discharge
3. Verify high-voltage system is disabled using manufacturer lockout/tagout procedure
4. Raise vehicle on lift or securely support on jack stands at manufacturer lift points
5. Remove front undertray and EDU splash shields to access transmission
6. Allow EDU to cool to ambient temperature if vehicle was recently driven
7. Connect scan tool and document all existing diagnostic trouble codes
8. Take photos of electrical connector routing for reference during reassembly

Procedure

1. 1

   Drain EDU transmission fluid
   Position drain pan beneath EDU drain plug. Remove drain plug using appropriate socket and allow fluid to drain completely (approximately 10-15 minutes). Inspect drained fluid for metallic debris or contamination. Clean drain plug and mating surface, then install new crush washer on drain plug.
   Torque spec

   Drain Plug34 Nm (25 lb-ft)
2. 2

   Remove EDU protective covers
   Locate and remove the EDU upper cover by removing cover screws in a criss-cross pattern. Carefully lift cover away, being mindful of any attached breather hoses or vent tubes. Set aside cover and gasket (note gasket condition for replacement).
   ⚠Do not allow dirt or debris to enter the EDU housing. Cover openings with clean lint-free shop towels when not actively working.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
3. 3

   Locate input speed sensor
   Identify the input speed sensor on the EDU housing. On the Bolt EUV, this is typically located on the upper driver's side of the transmission case, near the drive unit input shaft. The sensor will have a 2-wire electrical connector attached.
4. 4

   Disconnect electrical connector
   Depress the connector locking tab using a small pick or screwdriver while gently pulling the connector away from the sensor. Do not pull on wires themselves. Inspect connector pins for corrosion, damage, or bent terminals. Clean connector if necessary using electrical contact cleaner.
5. 5

   Remove input speed sensor
   Remove the sensor mounting bolt(s) using appropriate socket. Carefully extract the sensor from the EDU housing with a gentle rocking motion. Residual fluid may drain from the sensor bore. Remove and discard the old O-ring seal from the sensor or bore.
   ⚠Do not use excessive force or pry against the sensor body, as the sensor bore is machined aluminum and can be damaged.
   Torque spec

   Sensor Bolts11 Nm (8 lb-ft)
6. 6

   Inspect sensor bore and prepare new sensor
   Clean the sensor mounting bore thoroughly using a lint-free cloth. Inspect bore for damage, scoring, or debris. Clean mounting surface on EDU case. Lubricate new O-ring seal with clean Dexron VI ATF and install on new sensor. Verify new sensor part number matches original.
7. 7

   Install new input speed sensor
   Carefully insert new sensor into bore, ensuring O-ring does not twist or roll. Seat sensor fully into housing. Install sensor mounting bolt and torque to specification.
   Torque spec

   Sensor Bolts11 Nm (8 lb-ft)
8. 8

   Reconnect electrical connector
   Firmly press electrical connector onto new sensor until locking tab clicks into place. Gently tug on connector to verify secure connection. Route wiring harness to original position and secure any clips or retainers.
9. 9

   Reinstall EDU covers
   Install new EDU cover gasket if required (reuse if in good condition per GM service information). Position cover and install cover screws finger-tight, then torque in criss-cross pattern to specification. Reconnect any breather hoses or vent tubes.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
10. 10

    Refill EDU with transmission fluid
    Locate fill plug on EDU case. Remove fill plug and use fluid transfer pump to add approximately 2 quarts of ACDelco Dexron VI ATF (or amount drained). Fill until fluid begins to seep from fill hole, indicating proper level. Install fill plug and torque to specification.
    ℹ️EDU fluid capacity for this service is approximately 2 quarts. Total system capacity is 13.5 quarts but only fluid from accessible portions will drain.
    Torque spec

    Fill Plug34 Nm (25 lb-ft)
11. 11

    Reinstall underbody protection
    Install EDU splash shields and front undertray. Verify all fasteners are secure. Lower vehicle to ground.
12. 12

    Reconnect battery and perform system relearn
    Reconnect 12V negative battery cable. Turn ignition to ON position (do not start/activate drive mode). Using scan tool, clear any diagnostic trouble codes related to input speed sensor. Perform transmission sensor relearn procedure per GM service information if required.

Reassembly

1. Verify all electrical connectors are fully seated with locking tabs engaged
2. Confirm all EDU covers and shields are properly installed and torqued
3. Check for any fluid leaks around sensor, drain plug, and fill plug
4. Ensure no tools or parts were left in engine compartment or under vehicle
5. Verify 12V battery is reconnected with clean, tight connections

Verification

• With vehicle in PARK and brake applied, activate READY mode and verify no warning lights on instrument cluster
• Using scan tool, verify input speed sensor is providing valid signal and reading matches expected value (0 MPH at rest)
• Perform test drive at various speeds and verify input speed sensor data is consistent and no trouble codes return
• Monitor for proper gear engagement and smooth operation during test drive
• Re-check EDU fluid level after test drive (at operating temperature) and top off if necessary
• Verify no fluid leaks from sensor, drain plug, fill plug, or cover gasket after test drive
• Confirm all diagnostic trouble codes related to input speed sensor remain cleared after completion

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