Knock Sensor Malfunction

DTC P0325, P0326 DETECTION CONDITION & POSSIBLE CAUSES

DTC P0325, P0326	KNOCK SENSOR MALFUNCTION
DETECTION CONDITION	P0325 indicates a knock sensor circuit malfunction. P0326 indicates a knock sensor has detected vibrations (voltage generated based on this vibration) upon an increase and decrease in engine rpm that is outside a calibrated level.
POSSIBLE CAUSE	Knock sensor circuit short to GND Knock sensor circuit short to PWR Open knock sensor circuit Damaged knock sensor Damaged powertrain control module (PCM)
HINT	Knock Sensor Description A tuned accelerometer on the engine that converts engine vibration to an electrical signal. The PCM uses this signal to determine the presence of engine knock and retard spark timing if necessary.
Courtesy of MAZDA MOTORS CORP.
Courtesy of MAZDA MOTORS CORP.
Courtesy of MAZDA MOTORS CORP.

DTC P0325, P0326 DIAGNOSTIC PROCEDURE

DTC P0325, P0326		KNOCK SENSOR MALFUNCTION
STEP	INSPECTION		ACTION
1	Was the PCM quick test performed?	Yes	Go to next step.
1	Was the PCM quick test performed?	No	Perform PCM quick test. See PCM QUICK TEST .
2	CHECK VOLTAGE BETWEEN SENSOR AND SIG RTN Verify KS is installed properly and connector is connected. Complete comprehensive repair verification drive cycle. See DRIVE CYCLES . 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 4.
3	CHECK KS RESISTANCE Disconnect KS. Disconnect PCM. Install breakout box, leave PCM disconnected. Measure the resistance between PCM test pin 32 and PCM test pin 57. 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 step 7. For resistances less than 4.39 megaohms, Go to step 5.
4	CHECK FOR OPEN OF KS+ CIRCUIT Measure the resistance of KS+ circuit between PCM test pin 57 and the KS harness connector. Is resistance less than 5.0 ohms?	Yes	Replace KS. See KNOCK SENSOR (KS) REMOVAL / INSTALLATION - 2.3L KNOCK SENSOR (KS) REMOVAL / INSTALLATION - 3.0L or KNOCK SENSOR (KS) REMOVAL / INSTALLATION - 4.0L . 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 57 and the KS harness connector. Measure the resistance of KS- circuit between PCM test pin 32 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 57 and battery negative post. Is the bias voltage reading for CKP(-) less than 1.0 V?	Yes	Replace PCM. See POWERTRAIN CONTROL MODULE (PCM) REMOVAL / INSTALLATION . 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. See KNOCK SENSOR (KS) REMOVAL / INSTALLATION - 2.3L KNOCK SENSOR (KS) REMOVAL / INSTALLATION - 3.0L or KNOCK SENSOR (KS) REMOVAL / INSTALLATION - 4.0L . Go to step 8.
7		No	Replace PCM. See POWERTRAIN CONTROL MODULE (PCM) REMOVAL / INSTALLATION . Go to next step.
8	CHECK FOR CORRECT PCM OPERATION Disconnect PCM connector. Check for: corrosion pushed-out pins Connect PCM connector and make sure it is seated correctly. Complete comprehensive repair verification drive cycle. See DRIVE CYCLES . Is the concern still present?	Yes	Replace PCM. See POWERTRAIN CONTROL MODULE (PCM) REMOVAL / INSTALLATION . Test the system for normal operation.
8		No	If any other DTC is present, Go to applicable DTC inspection. See DIAGNOSTIC TROUBLE CODE (DTC) INDEX - POWERTRAIN CONTROL MODULE (PCM) . If no DTC is present, troubleshooting is complete.