Replaced oil pressure sensor and while I had the intake off replaced the knock sensors as suggested .{old ones worked fine)
Check engine light comes on ,which is caused by the knock sensors according to the codes.
After resetting the codes a half dozen times they reappear consistently after every second start up.
Vehicle seems to run normal.( 2002 convertible )
Hello and welcome to the forum ! You may want to post your question in the “ Corvette general discussion “ forum as well as it will probably be seen by more viewers. In the meantime I found this……might be something here that helps hopefully. Good luck with this issue.
C5 Corvette knock sensors can cause the check engine light (CEL) to turn on, often triggering codes like P0327 and P0332, which indicate low input from the knock sensors. This usually means the sensors are either faulty or there is a wiring issue, such as corrosion or brittle wiring harnesses due to heat exposure.
Key points about C5 knock sensor issues:
• Knock sensors detect engine vibrations from spark knock (abnormal combustion) to help the engine computer adjust ignition timing and prevent damage.
• The sensors are located under the intake manifold, so accessing them requires removing the intake.
• Common causes for CEL with knock sensor codes include bad sensors, wiring problems, or even PCM (engine computer) faults.
• Simply replacing the sensors may not fix the problem if wiring or connectors are corroded or damaged; replacing the wiring harness is often recommended during sensor replacement.
• Symptoms include the CEL turning on after driving some miles, pinging noises, and sometimes poor engine performance.
• Some owners report the CEL turning off randomly, possibly due to intermittent wiring or computer issues, but the light often returns if the root cause isn’t fixed.
Summary:
If your C5 Corvette’s check engine light comes on with knock sensor codes, start by checking and possibly replacing the knock sensors and their wiring harness under the intake manifold. Also inspect for corrosion or damaged connectors. If problems persist, the PCM or other engine management components may need diagnosis. Clearing codes and driving 20-50 miles can help confirm if the issue is resolved.
Yes, you can test the knock sensor wiring harness for faults using a multimeter and other tools by following these steps:
• Measure Resistance: Disconnect the knock sensor connector and measure resistance across the wiring harness terminals leading to the ECU. A normal resistance reading should be around 0.1 ohms. Significant deviation indicates wiring faults like breaks or shorts in the harness.
• Check Continuity and Ground: Test continuity between the sensor connector pins and the ECU pins to ensure wiring integrity. Also measure resistance between the sensor wiring and ground to detect shorts.
• Test Voltage Signal: With the engine running at idle, use an oscilloscope or multimeter set to AC volts to check for voltage signals at the sensor connector. Tap gently on the engine block near the sensor; a good harness and sensor will show voltage spikes. No or weak signals suggest wiring or sensor issues.
• Visual Inspection: Inspect the wiring harness for corrosion, damaged connectors, or brittle wires, especially near the intake manifold where heat can degrade wiring.
• Key-On Power Test: You can turn the key to the ON position (engine off) and test for proper voltage supply and ground at the sensor connector to verify wiring power and ground circuits.
If resistance or continuity tests fail, or voltage signals are absent or weak, the wiring harness is likely faulty and may need repair or replacement. Combining these electrical tests with sensor testing helps isolate whether the problem is in the wiring or the knock sensor itself.
