DESCRIPTION
The ECM constantly generates 5 V of power from the battery voltage supplied to the +B (BATT) terminal to operate the microprocessor. The ECM also provides this power to the sensors through the VC output circuit.
When the VC circuit is short-circuited, the microprocessor in the ECM and sensors that are supplied with power through the VC circuit are inactivated because the power is not supplied from the VC circuit. Under this condition, the system does not start up and the MIL does not illuminate even if the system malfunctions.
Tech Tips
Under normal conditions, the MIL is illuminated for several seconds when the ignition switch is first turned ON. The MIL goes off when the engine is started.
WIRING DIAGRAM
INSPECTION PROCEDURE
Note
After replacing the ECM, the new ECM needs registration Click here and initialization Click here.
PROCEDURE
CHECK MIL
Check that the Malfunction Indicator Lamp (MIL) lights up when turning the ignition switch to ON.
Result | Proceed to |
---|---|
MIL illuminates | A |
MIL does not illuminate | B |
A |
END |
B |
CHECK COMMUNICATION BETWEEN INTELLIGENT TESTER AND ECM
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and tester on.
Check the communication between the tester and ECM.
Result | Proceed to |
---|---|
Communication is possible | A |
Communication is not possible | B |
A |
GO TO MIL CIRCUIT Click here |
B |
CHECK MIL (ACCELERATOR PEDAL POSITION SENSOR)
Disconnect the accelerator pedal position sensor connector.
Turn the ignition switch to ON.
Check the MIL.
Result | Proceed to |
---|---|
MIL illuminates | A |
MIL does not illuminate | B |
Reconnect the accelerator pedal position sensor connector.
A |
REPLACE ACCELERATOR PEDAL ROD ASSEMBLY Click here |
B |
CHECK MIL (DIESEL THROTTLE BODY ASSEMBLY)
Disconnect the diesel throttle body assembly connector.
Turn the ignition switch to ON.
Check the MIL.
Result | Proceed to |
---|---|
MIL illuminates | A |
MIL does not illuminate | B |
Reconnect the diesel throttle body assembly connector.
A |
REPLACE DIESEL THROTTLE BODY ASSEMBLY Click here |
B |
CHECK MIL (FUEL PRESSURE SENSOR)
Disconnect the fuel pressure sensor connector.
Turn the ignition switch to ON.
Check the MIL.
Result | Proceed to |
---|---|
MIL illuminates | A |
MIL does not illuminate | B |
Reconnect the fuel pressure sensor connector.
A |
REPLACE COMMON RAIL Click here |
B |
CHECK MIL (EGR VALVE ASSEMBLY)
Disconnect the EGR valve assembly connector.
Turn the ignition switch to ON.
Check the MIL.
Result | Proceed to |
---|---|
MIL illuminates | A |
MIL does not illuminate | B |
Reconnect the EGR valve assembly connector.
A |
REPLACE EGR VALVE ASSEMBLY Click here |
B |
CHECK MIL (MANIFOLD ABSOLUTE PRESSURE SENSOR)
Disconnect the manifold absolute pressure sensor connector.
Turn the ignition switch to ON.
Check the MIL.
Result | Proceed to |
---|---|
MIL illuminates | A |
MIL does not illuminate | B |
Reconnect the manifold absolute pressure sensor connector.
A |
REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR Click here |
B |
CHECK HARNESS AND CONNECTOR
Disconnect the accelerator pedal position sensor connector.
Disconnect the diesel throttle body assembly connector.
Disconnect the fuel pressure sensor connector.
Disconnect the EGR valve assembly connector.
Disconnect the manifold absolute pressure sensor connector.
*1 | Front view of wire harness connector (to ECM) |
*2 | Front view of wire harness connector (to ECM) |
Disconnect the ECM connectors.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Reconnect the accelerator pedal position sensor connector.
Reconnect the diesel throttle body assembly connector.
Reconnect the fuel pressure sensor connector.
Reconnect the EGR valve assembly connector.
Reconnect the manifold absolute pressure sensor connector.
Reconnect the ECM connectors.
NG |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
OK |
REPLACE ECM Click here