Test K - Code 25/Knock Sensor
- Prepare vehicle for Engine Running Test. Using a 4 oz. hammer, prepare to tap on driver's side exhaust manifold, directly above the knock sensor, when the Dynamic Response Signal is given. Perform Engine Running Test. Tap moderately on exhaust manifold when the meter indicates Dynamic Test is ready. After 15 seconds a code will be generated. If code 25 is not present, knock system is ok, repeat Engine Running Test and service codes as necessary. If code 25 is present, proceed with test.
- Disconnect knock sensor connector and inspect. Connect voltmeter positive lead to harness circuit 310 and negative lead to circuit 359. Measure voltage. If voltage is less than 1 volt, proceed to step 3). If voltage is more than 4 volts, proceed to step 5). If voltage is between 1 and 4 volts, proceed to step 6).
- Turn ignition off and wait 10 seconds. Disconnect processor and inspect both 60 pin connectors. Connect breakout box to harness. Leave processor disconnected. Measure continuity from circuit 310 to breakout box pin 23 and circuit 359 to breakout box pin 46. If either resistance is 5 ohms or more, repair wiring harness and repeat Quick Test. If both resistances are less than 5 ohms, proceed with test.
- Turn ignition off and wait 10 seconds. Connect breakout box. Measure resistance circuit 310 to pins 40, 46 and 60. If any resistance is less than 10,000 ohms, repair harness short and repeat Quick Test. If all resistances are 10,000 ohms or more, proceed with test.
- Turn ignition off and wait 10 seconds. Disconnect processor and inspect both 60 pin connectors. Connect breakout box to harness. Leave processor disconnected. Turn ignition on. Connect voltmeter positive lead to breakout box pin 23 and negative lead to pin 40. Measure voltage. If voltage is more than .5 volts, repair harness short to power and repeat Quick Test. If voltage is less than .5 volts, proceed with test.
- Plug a substitute knock sensor into harness (DO NOT install). Perform Engine Running Test. Lightly tap knock sensor with 4 oz. hammer when Dynamic Test ready signal is given. After 15 seconds a code will be generated. If code 25 is present, replace processor and remove substitute knock sensor. Repeat Quick Test with original knock sensor.