Many malfunctions in the electrical system are caused by poor harness(s) and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
Check the following conditions:
Check for damaged harness and terminals: contact resistance, oxidation, bent or broken terminals.
Check for poor connection between ECM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection
Use a suitable male pin to ensure that contact in sockets is good. The pin should remain in position when pulled gently.
Has a problem been found?
YES
Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
System OK. Go to "Verification of Vehicle Repair" procedure
Turn ignition switch to OFF and disconnect Knock sensor connector.
Measure voltage of Knock sensor signal circuit between Knock sensor harnece connector and ECM harnece connector.
Probe(+) : Knock sensor harness connector NO1.
Probe(-) : Chassis ground.
Specification: 0.4V
Is signal voltage within specification?
YES
Go to "SHORT CIRCUIT INSPECTION FOR SIGNAL"
NO
In case over 5V : Short circuit to battery between Knock sensor harness connector and ECM harness connector
In case 0V: Open or Short circuit between Knock sensor harness connector and ECM harness connector
Repair as necessary and go to "Verification of Vehicle Repair" procedure
1.In case,when knock sensor connector is disconnected,the voltage at terminal 1 is 0V.
▶Possible cause : Open or short to ground and faulty ECM.
Turn ignition switch to OFF and disconnect Knock sensor connector and ECM connector.
Measure resistance between Knock sensor harness connector and chassis ground at Knock sensor signal circuit.
Probe(+) : Knock sensor harness connector NO1.
Probe(-) : Knock sensor harness connector NO2 and Chassis ground.
Specification: infinite
Does each resistance indicate open circuit?
YES
Go to "OPEN CIRCUIT INSPECTION FOR GROUND"
NO
Short circuit to chassis ground between Knock sensor harness connector and ECM harness connector
Short circuit between Knock sensor signal line and ground line
Repair as necessary and go to "Verification of Vehicle Repair" procedure
Turn ignition switch to OFF and disconnect Knock sensor connector.
Turn ignition switch to ON.
Measure resistance or voltage of Knock ground circuit between Knock sensor harnece connector and chassis ground.
Probe(+) : Knock sensor harness connector NO1 and NO2.
Probe(-) : Chassis ground.
Specification: below 1Ω,below 0.5V
Does each resistance or voltage indicate continuity circuit?
YES
Go to "Component Inspection"
NO
Open circuit between Knock sensor harness connector and ECM harness connector
Open circuit between ECM harness connector and chassis ground
Repair as necessary and go to "Verification of Vehicle Repair" procedure
In case,when checking the open ground circuit,the resistance is infinite.
▶Possible cause : Open circuit in ground line.
