Engine Control System 1A-55
Step
Action
Value(s)
Yes
No
1
Perform the "On-Board Diagnostic (OBD)
System Check".
Was the OBD System Check performed?
—
Go to Step 2
Refer to OBD
System Check
and go to Step 2
2
Check the circuit between ECM and CHECK
ENGINE lamp for short to ground.
1.
Starter switch "OFF".
2.
Disconnect the ECM.
3.
Starter switch "ON", and observe the
CHECK ENGINE lamp.
Is the CHECK ENGINE lamp "OFF"?
—
Go to Step 4
Go to Step 3
3
Repair or replace the harness between ECM
and CHECK ENGINE lamp.
Is the action complete?
—
Verify repair and
go to Step 10
—
4
Check the diagnostic switch circuit for open
wiring.
1.
Disconnect the ECM.
2.
Short DLC pins 4 and 6.
3.
Check the continuity between ECM
connector pin and ground (e.g., frame or
body).
Is the circuit in normal condition?
ECM pin 112-
ground:
Continued
Go to Step 8
Go to Step 5
5
Check the DLC ground circuit for open wiring.
1.
Check the continuity between DLC pin
and ground (e.g., frame or body).
Is the circuit in normal condition?
DLC 4/5 pin-
ground:
Continued
Go to Step 7
Go to Step 6
6
Repair or replace the DLC ground circuit
harness.
Is the action complete?
—
Verify repair and
go to Step 10
—
7
Repair or replace the harness between ECM
and DLC pin 6.
Is the action complete?
—
Verify repair and
go to Step 10
—
8
Re-observe the CHECK ENGINE lamp for
operation.
1.
Certainly connect connectors.
2.
Short DLC pins 4 and 6.
3.
Starter switch "ON", and observe the
CHECK ENGINE lamp.
Does the CHECK ENGINE lamp blink?
—
Refer to
"Diagnostic Aids"
Go to Step 9
9
1.
Replace the ECM.
Important:
If necessary (for the vehicle equipped with
idle stop function), input the number of
startups to the replacing ECM.
Is the action complete?
—
Verify repair and
go to Step 10
—