Code 25; No Knock.
Senior User
Joined: Sep 2004
Posts: 484
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From: SC lowcountry
I checked in 95 manual for code 25 not listed then checked knock sensor problems and found code 225 for 95 - said altitude over 6000 ft could cause code to occur; code is triggered from "Goose " test in KOER sequence. Said to rerun test - I guess goose is variable to operator. Only faults listed were bad knock sensor and bad PCM. Sensor send input to PCM to retard timing if knock (detonation?) occurs. I would take the results with a grain of salt if it were mine.
Senior User
Joined: Nov 2002
Posts: 158
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From: Champlin USA
from my haynes manual,
A quick check for the knock sensor is to simulate operating conditions. With the engine running and a timing light hooked up, tap the engine manifold next to the knock sensor with a hammer and observe that the timing retards momentarily. If there is no response, check for reference voltage. Disconnect the electrical connector from the knock sensor and with the ignition key ON (engine not running), check for reference voltage from the computer. There should be approximately 5.0 volts. To replace the sensor, simply unscrew it. Install the new sensor, tightening it securely.
A quick check for the knock sensor is to simulate operating conditions. With the engine running and a timing light hooked up, tap the engine manifold next to the knock sensor with a hammer and observe that the timing retards momentarily. If there is no response, check for reference voltage. Disconnect the electrical connector from the knock sensor and with the ignition key ON (engine not running), check for reference voltage from the computer. There should be approximately 5.0 volts. To replace the sensor, simply unscrew it. Install the new sensor, tightening it securely.
