SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 181 (ENGINE CONTROLS - SELF-DIAGNOSTICS - 2.2L)DIAGNOSTIC TESTSDTC P0327: KNOCK SENSOR CIRCUITDIAGNOSTIC PROCEDURES
1999 GMC Forward Control 5.7 R, Automatic

Diagnostic Procedures

1999 GMC Forward Control 5.7 R, AutomaticSECTION Diagnostic Procedures
WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
    2. NOTE: If an engine mechanical noise can be heard, repair the condition before proceeding with this test.
  2. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC fail this ignition? If yes, go to next step. If no, go to DIAGNOSTIC AIDS .
  3. Turn ignition off. Disconnect the knock sensor. Measure the resistance from the KS signal circuit on the sensor side of the KS harness connector to a good ground with the DVOM. Measure the resistance from the KS low reference circuit on the sensor side of the KS harness connector to a good ground with the DVOM. Does the DVOM display an open for both circuits? If yes, go to next step. If no, go to step  8.
  4. Connect the DVOM from the KS signal circuit to the KS low reference circuit on the sensor side of the KS harness connector. Set the DVOM to the 400 mV AC hertz scale and wait for the DVOM to stabilize at zero Hz. DO NOT tap on plastic engine components. Tap on the engine block with a non-metallic object near the KS while observing the signal indicated on the DVOM. Does the DVOM display a fluctuating frequency while tapping on the engine block? If yes, go to next step. If no, go to step  8.
  5. Turn ignition on, with engine off. On the ECM side of the KS harness connector, measure the DC voltage from the KS signal circuit to a good ground with a DVOM. On the ECM side of the KS harness connector, measure the DC voltage from the KS low reference circuit to a good ground with a DVOM. Is the voltage greater than 0.5 volt on any circuit? If yes, go to next step. If no, go to step  7.
  6. Turn ignition off. Disconnect the ECM. Test KS signal circuit or the KS low reference circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  12. If no, go to step  9.
  7. Turn ignition off. Disconnect the ECM. Test KS signal circuit and the KS low reference circuit for an open, short to ground, high resistance or short between both circuits. Did you find and correct the condition? If yes, go to step  12. If no, go to step  9.
  8. Test for an intermittent and for a poor connection at the KS. Did you find and correct the condition? If yes, go to step  12. If no, go to step  10.
  9. Test for an intermittent and for a poor connection at the ECM. Did you find and correct the condition? If yes, go to step  12. If no, go to step  11.
  10. Replace KS. After replacing sensor, go to step  12.
  11. Turn ignition off. Replace ECM. Perform ECM relearn procedure. See ELECTRONIC CONTROL MODULE REPROGRAMMING  under PROGRAMMING. After replacing ECM, go to next step.
  12. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running the DTC. See CONDITIONS FOR RUNNING DTC . You may also operate vehicle within the conditions observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step  2. If no, go to next step.
  13. With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.