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Home >> Isuzu >> 1996 >> Hombre S >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Circuit Testing >> DTC P0325 - Knock Sensor Circuit >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) System Check. After performing OBD system check, go to next step.
  2. Start engine. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Operate engine at 10 percent throttle angle. Check Malfunction Indicator Light (MIL). If MIL is on, go to 4). If MIL is off, go to next.
  3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If MIL is on, go to next step. If MIL is off, go to step 15)
  4. While listening to engine, raise and lower engine RPM. If an audible noise or knock is present, go to next step. If no audible noise or knock is present, go to step 6)
  5. Repair cause of engine noise or knock. After repair is completed, go to step 15).
  6. Slowly increase engine speed to 2500 RPM. Using scan tool, monitor KS activity. If KS activity increases with engine speed, go to next step. If KS activity does not increase with engine speed, go to step 11).
  7. Check for a poor KS signal circuit terminal connection at PCM connector. Repair as necessary. After repair is completed, go to step 15). If terminal connection is okay, go to next step.
  8. If KS module has previously been replaced, go to next step. If KS module has not previously been replaced, go to step 10).
  9. Replace PCM. Program replacement PCM using required equipment. After repair is completed, go to step 15).
  10. Replace KS module. After repair is completed, go to step 15).
  11. Turn ignition off. Disconnect PCM connectors. Measure resistance between ground and signal circuit terminal at PCM connector. If resistance is 90-110 k/ohms, go to step 7). If resistance is not 90-110 k/ohms, go to next step.
  12. Check KS connector for poor connection. Repair as necessary. After repair is completed, go to step 15). If connector is okay, go to next step.
  13. Check KS signal circuit for an open, short to ground or short to voltage. Repair as necessary. After repair is completed, go to step 15). If circuit is okay, go to next step.
  14. Replace KS. After repair is completed, go to next step.
  15. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0325. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2).
  16. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.
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