
Maintenance Manual for J2 Sedan
Electronic Control System
of Engine
196
1. Description
Knock sensor is installed in the cylinder block side usually between the 2, 3-cylinder, it is helpful for
engine knock balance; the ECU uses the knock sensor output vibration frequency signal to judge
whether there is knock with ECU internal filtering. When the knock signal is detected, ECU will
gradually reduce it until the knock disappeared; and then gradually restore to the knock threshold; the
cycle is done repeatedly.
2. Installation position
Installed aside of cylinder.
3. Inspection
1) Wiring diagram
Pin 30: Terminal A of knock sensor
Pin 31: Terminal B of knock sensor
2) Check the resistance.
Resistance: greater than 1M
Ω
4. Diagnosis:
ECU monitors the knock sensor, power amplifier circuit and testing circuit. If one of the following
circumstances is detected, knock sensor fault indication will be set:
Knock sensor failure;
Knock control data processing circuit fault;
Fig. 4.3.019
Knock sensor