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Knock Sensor Malfunction

NOTE: The following test procedures are for DTCs P0325 and P0326.

Fig 1: Knock Sensor Malfunction Detection Condition Possible Cause

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Courtesy of MAZDA MOTORS CORP.

KNOCK SENSOR MALFUNCTION INSPECTION/ACTION CHART

STEP	INSPECTION		ACTION
1	Was PCM Quick Test performed?	Yes	Go to next step.
1	Was PCM Quick Test performed?	No	Perform PCM Quick Test. See PCM QUICK TEST .
2	CHECK VOLTAGE BETWEEN SENSOR AND SIG RTN Verify KS sensor is installed properly and connector is connected. Complete the repair verification drive cycle. See DRIVE CYCLE . Key ON, Engine OFF (KOEO). Access KSI PID. Is KSI PID less than 0.5 volts?	Yes	Key OFF. Go to next step.
2		No	Go to step 6.
3	CHECK KS SENSOR RESISTANCE Disconnect PCM. Install Breakout Box, leave PCM disconnected. Measure the resistance between PCM test pin E20 and PCM test pin E32. Is the resistance between 4.39 and 5.35 megaohms?	Yes	Go to step 7.
3		No	For resistances greater than 5.35 megaohms, go to next step. For resistances less than 4.39 megaohms, go to step 5.
4	CHECK FOR OPEN OF KS+ CIRCUIT Disconnect KS sensor. Measure the resistance of KS+ circuit between PCM test pin E32 and the KS pin 2, circuit (Y/R). Is the resistance less than 5.0 ohms?	Yes	Replace KS sensor, see KNOCK SENSOR (KS) -- 2.3L . Go to step 8.
4		No	Repair open circuit. Go to step 8.
5	CHECK KS+ CIRCUIT FOR SHORT TO GROUND IN HARNESS Measure the resistance of KS+ circuit between PCM test pin E32 and chassis ground. Measure the resistance of KS-circuit between PCM test pin E20 and chassis ground. Is the resistance greater than 10K ohms?	Yes	Go to next step.
5		No	Repair short circuit. Go to step 8.
6	CHECK KS CIRCUITS FOR SHORT TO POWER IN HARNESS Connect PCM to Breakout Box. Key ON, Engine OFF (KOEO). Measure the voltage of KS+ circuit between PCM test pin E32 and battery negative post. Measure the voltage of KS-circuit between PCM test pin E20 and battery negative post. Was bias voltage reading less than 1.0 V?	Yes	Replace PCM, see POWERTRAIN CONTROL MODULE (PCM) . Go to step 8.
6		No	Repair short circuit. Go to step 8.
7	CHECK PCM FOR SHORT TO GROUND Measure the resistance between KS+ and KS-circuits at the KS harness connector. Is the resistance greater than 10K ohms?	Yes	Replace KS sensor, see KNOCK SENSOR (KS) -- 2.3L . Go to next step.
7		No	Replace PCM, see POWERTRAIN CONTROL MODULE (PCM) . Go to next step.
8	VERIFY TROUBLESHOOTING OF DTCs COMPLETED Make sure to reconnect all disconnected connectors. Clear DTCs from PCM memory using WDS or equivalent tester generic OBD II function. Perform PCM Quick Test. See PCM QUICK TEST . Is any DTC present?	Yes	Replace PCM, see POWERTRAIN CONTROL MODULE (PCM) . Repeat PCM Quick Test. See PCM QUICK TEST .
8		No	If any other DTC is present, go to applicable DTC inspection. If no DTC is present, troubleshooting complete.