Diagnostic Instructions
DTC Descriptor
DTC 016: Knock Sensor (KS) Module Performance
DTC 018: Knock Sensor (KS) Circuit
Circuit/System Description
The knock sensor (KS) enables the engine control module (ECM) to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The KS produces an AC voltage signal that varies
depending on the vibration level during engine operation. The ECM adjusts the spark timing based on the amplitude and the frequency of the KS signal. The ECM receives the KS signal through a signal circuit. The ECM supples a ground circuit to the KS through
a low reference circuit. The ECM also supplies a shielded ground circuit to the KS. The ECM learns a KS noise level at idle and uses calibrated values for the rest of the engine speed range. The ECM should monitor a normal KS signal within the noise channel.
The circuits between the KS sensor and the ECM consist of the following circuits:
Conditions for Setting the DTC
016
| • | Then engine speed is greater than 2,000 RPM. |
| • | Maximum integrated value is greater than 183. |
| • | Minimum integrated value is less than 4. |
| • | The set-up time is greater than 26 seconds. |
| • | The battery voltage is greater than 9 volts. |
| • | The DTC runs continously once the above conditions are met. |
018
| • | The engine speed is above 2,400 RPM. |
| • | Maximum integrated value is above 110 for at least 2 seconds. |
| • | Minimum integrated value is below 1 for at least 2 seconds. |
| • | Noise value is above 55 counts for at least 5 seconds. |
| • | Noise value is below 0 counts for at least 5 seconds. |
| • | The DTC runs continously once the above conditions are met. |
Diagnostic Aids
The following conditions could also set this DTC:
| • | Inspect the KS for physical damage. A KS that is dropped or damaged may cause a DTC to set. |
| • | Inspect the KS for proper installation. A KS that is loose or over torqued may cause a DTC to set. The KS should be free of thread sealant. The KS mounting surface should be free of burrs, casting flash, and foreign material. |
| • | The KS must be clear of hoses, brackets, and engine electrical wiring. |
| • | An electromagnetic interference (EMI) condition on the shielded ground circuit |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Start the engine, observe the DTC information with a scan tool. DTCs 016 and 018 should not set.
| ⇒ | If DTC 016 sets, replace the ECM. |
Circuit/System Testing
Important: If the knock sensor lead is damaged in any way, replace the knock sensor.
- Ignition OFF, disconnect the harness connector of the knock (KS) sensor.
- Ignition ON, connect a test lamp between the signal circuit of the KS and the negative battery terminal.
| ⇒ | If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuits/connections test normal, replace the ECM. |
- Ignition ON, connect a test lamp between the signal circuit of the KS and the positive battery terminal.
| ⇒ | If the test lamp illuminates, test the signal circuit for a short to ground. If the circuits/connections test normal, replace the ECM. |
- Ignition OFF, connect a DMM between the signal circuit and the low reference circuit.
- Test for 90-110K ohms between the signal circuit and the low reference circuit of the KS.
| ⇒ | If the resistance is not within the specified range, test the circuits for an open/high resistance. If the circuits/connections test normal, replace the ECM. |
- If all circuits/connections test normal, replace the KS sensor.
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
