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
Checking open circuit of MAP signal line is to find whether there is open or short circuit in MAP harness.
Turn ignition switch to OFF and disconnect MAP connector.
Turn ignition switch to ON
Measure voltage of MAP signal circuit between MAP harness connector and ECM harness connector..
Probe(+) : MAP harness connector NO1.
Probe(-) : Chassis ground.
Specification: Approximately 5V
Is voltage within Specification?
YES
Go to "Inspection of open MAP ground line"
NO
Open circuit or short circuit to chassis ground between MAP harness connector and signal circuit.
Open circuit between MAP harness connector and ECM harness connector
Repair as necessary and go to "Verification of Vehicle Repair"
1.In case,when MAP connector is disconnected,the voltage of MAP terminal 1 is 0 V.
▶Possible cause: Open or short between terminal 37 of ECM and Terminal 1 of MAP
Checking open circuit of MAP signal line is to find whether there is open or short circuit in MAP harness.
Turn ignition switch to OFF and disconnect MAP sensor connector.
Turn ignition switch to ON
Measure voltage of MAP signal circuit between MAP harness connector and ECM harness connector.
Probe(+) : MAP harness connector NO4.
Probe(-) : Chassis ground.
Specification: below 0.5V, below 1Ω
Is voltage and resistance within Specification?
YES
Go to "Inspection of short between MAP signal and power line"
NO
Open circuit between MAP harness connector and ECM harness connector.
Repair as necessary and go to "Verification of Vehicle Repair"
1.In case,when MAP connector is disconnected,the resistance of MAP terminal 4 is infinite.
▶Possible cause: Open or short between terminal 36 of ECM and Terminal 4 of MAP.
Turn ignition switch to OFF and disconnect MAP connector and ECM harness connector.
Measure resistance between reference voltage(5V) circuit and signal circuit.
Probe(+) : MAP harness connector NO2.
Probe(-) : MAP harness connector NO1.
Specification: infinite
Is resistance within Specification?
YES
Go to "Component Inspection"proce
NO
Short circuit between reference voltage(5V) circuit and signal circuit.
Repair as necessary and go to "Verification of Vehicle Repair"
When the terminal 1and 2 of MAP is shorted, the resistence is below 1 ohm.
