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DTC P0325 (KNOCK): KNOCK SENSOR 1 (KS) CIRCUIT MALFUNCTION Subaru Forester SF

Testing & Diagnostics ~242 words
  1. Turn ignition off. Disconnect PCM connector. Using an ohmmeter, check resistance between ground and PCM connector terminal No. 3 (Blue/Red wire - Forester and Impreza or White wire - Legacy). If resistance is more than 700 k/ohms, go to next step. If resistance is between 400 k/ohms and 700 k/ohms, go to step 3). If resistance is less than 400 k/ohms, go to step 4).
  2. Disconnect KS connector. Check resistance between KS connector terminal No. 2 (Blue/White wire) and ground. If resistance is less than 700 k/ohms, check for an open in wiring between PCM and KS connector, or poor contact of KS connector. If resistance is more than 700 k/ohms, ensure KS installation bolt is secure. If installation bolt is loose, tighten securely. If installation bolt is secure, replace KS.
  3. Reconnect PCM. Turn ignition on. Using voltmeter connected to ground, backprobe PCM connector terminal No. 3 (Blue/Red wire on Forester and Impreza, or White wire on Legacy). If voltage reading is 2 volts or less, repair poor contact in PCM connector. If voltage reading is more than 2 volts, circuit is normal. Check for poor contact at KS or PCM connectors.
  4. Disconnect KS connector. Check resistance between KS terminal No. 2 and ground. If resistance is 400 k/ohms or less, replace KS sensor. If resistance is more than 400 k/ohms, check for short to ground in wiring between KS and PCM connectors.

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