Powertrain Controls - ECM/PCM

Diagnostic Chart.:

Knock Sensor Wiring.:

DESCRIPTION


The knock sensor is a piezoelectric device that produces an output voltage based on mechanical engine vibration. The PCM will retard the electronic spark timing on the signal being received. The circuitry within the knock sensor causes the PCM/EC five volts reference to be pulled down so that under a no knock condition, Circuit 496 would measure 2.5 volts. The knock sensor produces an AC signal. The amplitude and signal frequency is dependant upon the knock level. If CKT 496 becomes open or shorted to ground the voltage will either go above 3.5 volts or below 1.5 volts. If either of these conditions are met for about 10 seconds, a Code 43 will be set.

CODE PARAMETERS

^ Code 43 will set if the ESC voltage reading is out of range either high or low for at least 10 seconds.

DIAGNOSTIC AIDS

^ When attempting to diagnose an intermittent problem use the Scan Tool to review supplemental diagnostic information. The supplemental data can be used to duplicate a problem. Select MALF History from Scan Tool EC menu.


^ Voltage can be read on wire without disconnecting any connectors.

^ The resistance to ground through the knock sensor should be between 3300 and 4500 ohms.


^ Loose knock sensor could set PCM/EC Code 43.


Torque: 15 N m (133 in-lbs)