DTC 43
DTC 43
KNOCK SENSOR (KS) CIRCUIT 2.3L (VIN A) "L" CARLINE
Circuit Description:
The knock sensor detects engine detonation and the Engine Control Module (ECM) retards the electronic spark timing based on the signal being received. The knock sensor produces an AC signal which is used for knock detection. The amplitude and signal frequency are dependent upon the knock level. The ECM performs two test on this circuit to determine if it is operating correctly. If either of the tests fail, a DTC 43 will be set.
^ If there is an indication of knock for more than 4.54 seconds over a 5 second interval with the engine running.
^ If ECM terminal "BC13" does not indicate increasing Knock Sensor (KS) activity with engine speed.
Test Description: Number(s) below refer to circled number(s) on the diagnostic chart.
1. If the conditions for the test as described above are being met, DTC 43 will be currently set and the MIL (Service Engine Soon) will be illuminated.
2. If the engine has an internal problem which is creating a knock, the knock sensor may be responding to the mechanical noise.
3. The Tech 1 scan tool displays knock sensor activity in counts approximately 35-50 at idle. The counts should rise when engine speed increases or fall when engine speed decreases. This step checks knock sensor activity
4. This step checks that the internal resistance of knock sensor is within an acceptable range.
5. Check the knock sensor connections for loose terminals or corrosion. A faulty connection will set a DTC 43. If connections are OK, a faulty component will also set a DTC 43.
Diagnostic Aids:
Check CKT 496 for a potential open or short to ground. Also check for proper installation of the PROM. Refer to "Intermittents" in "Symptoms," Section "6E3-B" An "Intermittent" problem may be caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation. Any circuitry, that is suspected as causing the intermittent complaint, should be thoroughly checked for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wiring connections or physical damage to the wiring harness. Mechanical engine knock can cause a knock sensor signal. Abnormal engine noise must be corrected before using this chart.
ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK
The On-Board Diagnostic (OBD) system check is an organized approach to identifying a problem created by an electronic engine control system malfunction. It must be the starting point for any driveability complaint diagnosis, because it directs the service technician to the next logical step in diagnosing the complaint. The Tech 1 data listed in the table may be used for comparison, after completing the OBD system check and finding the on-board diagnostics functioning properly and no diagnostic trouble codes displayed. The "Typical Values" are an average of display values recorded from normally operating vehicles and are intended to represent what a normally functioning system would typically display. A SCAN TOOL THAT DISPLAYS FAULTY DATA SHOULD NOT BE USED, AND THE PROBLEM SHOULD BE REPORTED TO THE MANUFACTURER. THE USE OF A FAULTY SCAN CAN RESULT IN MISDIAGNOSIS AND UNNECESSARY PARTS REPLACEMENT. Only the parameters listed below are used in this manual for diagnosing. If a scan reads other parameters, the values are not recommended by General Motors for use in diagnosing. For more description on the values and use of the scan to diagnosis ECM inputs, refer to the applicable diagnosis section in Section "C". If all values are within the range illustrated, refer to "Symptoms," Section "B".