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Squealer! Stop Subaru throttle squeal

Secondary pressure sensor wire identification.
<p>Secondary pressure sensor wire identification.</p>

This bulletin provides an inspection and diagnosis method for the CVT’s secondary pressure sensor which if failed, could create a squealing-type sound during light throttle application.

1. Road test to confirm the condition and bring the transmission up to normal operating temperature.

2. Turn off the ignition and allow the vehicle to sit at least 10 minutes, while preparing the SSMIII and gaining access to the TCM (transmission control module) main wiring harness connector. This will allow the secondary pressure sensor sufficient time to fully drain off any residual pressure.

3. After connecting the SSMIII, confirm that the CVT’s fluid temperature is between 50 and 176 degrees F. DO NOT start the engine at any time while performing the following voltage checks.

4. Perform the following voltage checks on the TCM connector B54:

-          With the ignition switch ON and engine off, check the voltage between pin #2 (power supply) and #15 (ground). Specified value is 4.8 to 5.2 volts. If the voltages are outside of the specified range, the TCM is damaged, along with the pulley surfaces of the CVT due to chain slippage. Replace the TCM and the CVT assembly.

-          With the ignition switch ON and engine off, check voltage between pin #17 (pressure sensor output voltage) and #15 (ground). Specified value is 0.45 to 0.55 volts. If the voltages are outside of the specified range, the secondary pressure sensor is damaged along with the pulley surfaces of the CVT due to chain slippage. Replace the CVT assembly.

-          Important: Before ordering a new TCM and/or CVT, perform these same voltage checks at the secondary pressure sensor connector (AT6) and if necessary, the main transmission harness connectors T4 and B11. Ruling out wiring issues will prevent repeat or unnecessary component replacements.

Reminder: Whenever replacing the CVT assembly, TCM, control valve body or servicing the CVT fluid, the Learning Control procedure must be completed. Refer to the service manual.

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