Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2019 Subaru Ascent BaseFACTORY OEM SERVICE PROCEDURE
Secondary Speed Sensor: Inspection
- Remove the bulkhead wiring harness connector from TCM. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>TRANSMISSION CONTROL MODULE (TCM)>REMOVAL .
- Set the ST (CHECK BOARD) between the TCM and bulkhead wiring harness.
- Set the probe of oscilloscope to the check board connector.
Terminals:
No. 13 (+) - No. 26 (-):
- Start and warm up the engine.
- Check the waveform of secondary speed sensor with engine idling.NOTE: The waveform cycle changes as the speed changes.
Factory Service Tools
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.