Test Dg: Step 1

1) Code 25: Generate Knock Signal Manually  Code 25 indicates that the Knock Sensor (KS) signal was not received by the ECA during the dynamic response (Goose) test after the engine ID code in the KOER Self-Test. Possible causes for this fault are:

• Faulty knock sensor
• Open or shorted harness
• Faulty ECA

Have 4 oz. hammer ready. Ensure engine is at normal operating temperature. Perform KOER Self-Test. Immediately after DYNAMIC RESPONSE CHECK request signal appears, lightly tap above knock sensor with 4 oz. hammer. DO NOT  goose throttle. After 15 seconds, check for Code 25. Ignore all other codes at this time. If Code 25 is displayed, go to next step. If Code 25 is not displayed, knock system is okay. Repeat KOER Self-Test and service other codes.