When IG key is turned to ON, ECM get ON signal by 'ON/START input' terminal. This signal initializes(boots) ECM accordingly, main relay operates. Main relay supplies powers for ECM, sensors and actuators in order to enable engine to start. When "IG key ON" signal is shut off during turning engine OFF, ECM stops injector operation then engine turns OFF. Approx. after 16 ~ 20 sec., ECM shuts OFF main relay and system turns OFF.
When the condition that IG key ON signal turns OFF while ECM, to which IG signal inputted, is initialized (booting, Approx. 25ms is required), IG key switch error is recognized and P1652 is set (monitored only once every IG key ON initialization process). This code is due to poor connection in IG key ON signal circuit.
Item | Detecting Condition | Possible Cause | ||
DTC Strategy |
•
Voltage monitoring |
•
"IG key ON" signal circuit
•
IG key switch | ||
Enable Conditions |
•
Engine running | |||
Threshold Value |
•
No signal through IG line after "IG key ON". | |||
Diagnostic Time |
•
Immediately | |||
Fail Safe | Fuel Cut | NO |
•
- | |
EGR Off | NO | |||
Fuel Limit | NO | |||
Check Lamp | OFF | |||
Fig.1) The waveforms of "IG key ON" signal and main relay operation are measured simultaneously.
☞ Check poor connection at the point of IG key ON.
