3.
Engine :idle RPM
caution
The data shown above is only for reference and there may be a little difference actually.
This is the inspection procedure to determine whether it is present DTC or memoried one by monitoring the current signal or by using the function of oscilloscope with Hi-scan pro.
Connect scan tool to DLC.
IG KEY : ON
Engine :idle RPM
The data shown above is only for reference and there may be a little difference actually.
Service standard
Ignition switch ON : ON 1.5 sec ⇒OFF
Engine running : ON
Start engine.
Probe(+) : Check the waveform at terminal 2 of FUEL PUMP RELAY
Probe(-) : Chassis ground.
This signal fform shows how MAIN RELAY and FUEL PUMP operate each other.
Point ① is the duration ECM makes FUEL PUMP RELAY ON for 1.5 second after ignition switch ON.
Point ② is MAIN RELAY ON and its voltage should be over 12V.
Point ③ is where ECM makes FUEL PUMP ON when it detects starting RPM(50) with CKPS signal.
If the oprating sound of fuel pump relay is heard,when ignition key has been turned ON, the pump relay control system is considered normal.
In case DTC is displayed but FUEL PUMP RELAY is OK and no problem is found
The problem may be intermittent so slightly shake the connector and harness vertically and horizontally to check if there is any data changes
If the data changes normally, the problem was intermittent so erase DTC and verify the same DTC reoccure.
Go to "Terminal and Connector inspection" procedure.
In case there is symptom and wrong data with DTC
Check open,short or connector’s connection for RELAY
Check the deterioration of RELAY performance.
Go to "Signal circuit inspection" procedure.
This signal waveform shows how MAIN RELAY and FUEL PUMP operate each other.
Point ① is the duration ECM makes FUEL PUMP RELAY ON for 1.5 second after ignition switch ON.
Point ② is MAIN RELAY ON and its voltage should be over 12V.
Point ③ is where ECM makes FUEL PUMP ON when it detects starting RPM(50) with CKPS signal.
