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Code 2-5 Knock Detection System

Ensure that intake manifold was tapped with steel object within 2" from knock sensor. If not, re-test, and remove jumper wire from Self-Test Trigger.

  1. With ignition off, disconnect harness from knock sensor. Using 1 1/8" deep socket, loosen sensor and tighten to 12-18 ft. lbs. (16-24 N.m). Go to next step.
  2. Disconnect MCU connector. Connect ohmmeter between engine ground and Pin No. 13 of MCU connector. If resistance is less than 1K ohms, repair short circuit to ground, and re-test. If more than 1K ohms, go to next step.
  3. Check continuity between Pin No. 13 and knock sensor connector (Yel/Red wire). If less than 5 ohms, go to next step. If more than 5 ohms, repair circuit, and re-test.
  4. Check continuity between Pin No. 14 and knock sensor connector (Blk/Lt. Grn wire). If less than 5 ohms, connect MCU and go to next step. If more than 5 ohms, repair circuit, and re-test.
  5. Reconnect Self-Test Trigger jumper on Self-Test connector. Connect a test light to battery positive terminal. Disconnect knock sensor. Perform steps 1) and 2) of ENGINE RUNNING TEST. Instead of tapping manifold with rod, tap test lamp to Yellow/Red contact in knock sensor connector for 5 seconds.
  6. Observe voltmeter. If code 25 appears, replace MCU, and re-test. If any other code appears, replace knock sensor, and re-test.
Fig 1: Knock Detection System - Test Connections
G2518