The Malfunction Indicator Lamp (Mil) Is Never/Always On - Ford Mustang 2005 Workshop Manual

2005 Mustang Workshop Manual
P6 CHECK THE ENGINE OIL PRESSURE SWITCH (INDICATOR ALWAYS ON)
Ignition OFF.
Disconnect: Engine Oil Pressure Switch C103.
Connect a fused (5A) jumper wire between the engine oil pressure switch C103-1, circuit 208
(GY), harness side and ground.
Ignition ON.
Does the low oil pressure warning indicator illuminate?
P7 CHECK CIRCUIT 208 (GY) FOR AN OPEN
Ignition OFF.
Disconnect: SJB C2280c.
Measure the resistance between the SJB C2280c-42, circuit 208 (GY), harness side and the
engine oil pressure switch C103-1, circuit 208 (GY), harness side.
Is the resistance less than 5 ohms?
P8 CHECK FOR CORRECT SJB OPERATION
Disconnect all the SJB connectors.
Check for:
corrosion
pushed-out pins
Connect all the SJB connectors and make sure they seat correctly.
Operate the system and verify the concern is still present.
Is the concern still present?
P9 CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION
Disconnect the instrument cluster connector.
Check for:
corrosion
pushed-out pins
Connect the instrument cluster connector and make sure it seats correctly.
Operate the system and verify the concern is still present.
Is the concern still present?
Pinpoint Test Q: The Malfunction Indicator Lamp (MIL) Is Never/Always On
Normal Operation
The MIL is controlled by the instrument cluster using data sent from the powertrain control module (PCM) over the communication network.
Possible Causes
PCM
instrument cluster
PINPOINT TEST Q: THE MALFUNCTION INDICATOR LAMP (MIL) IS NEVER/ALWAYS ON
Q1 CARRY OUT THE INSTRUMENT CLUSTER WARNING LAMPS AND CHIME ACTIVE
COMMAND USING THE DIAGNOSTIC TOOL
Ignition ON.
Enter the following diagnostic mode on the scan tool: Instrument Cluster Active Command.
Select the instrument cluster warning lamps and chime active command. Trigger the all
lamps active command on and off. Observe the MIL indicator.
Does the MIL indicator illuminate when triggered on and turn off when triggered off?
Q2 CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION
Disconnect the instrument cluster connector.
Check for:
corrosion
pushed-out pins
Connect the instrument cluster connector and make sure it seats correctly.
Operate the system and verify the concern is still present.
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Test Step
No
REFER to Section 303-00 to continue diagnosis of the engine oil
pressure.
Yes
REMOVE the jumper wire. GO to P7 .
No
INSTALL a new engine oil pressure switch. CLEAR the DTCs. REPEAT
the self-test.
Yes
GO to P8.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
Yes
INSTALL a new SJB. REFER to Section 419-10. TEST the system for
normal operation.
No
The system is operating correctly at this time. The concern may have
been caused by a loose or corroded connector. CLEAR the DTCs.
REPEAT the self-test.
Yes
INSTALL a new instrument cluster. REFER to
this section. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have
been caused by a loose or corroded connector.
Result / Action to Take
Yes
GO to Q3.
No
GO to Q2.
Yes
INSTALL a new instrument cluster. REFER to
section. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been
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Instrument Cluster (IC) in
Instrument Cluster (IC) in this
11/14/2009