Pinpoint Test F: The Low Fuel Warning Indicator Is Never/Always On; Pinpoint Test G: The Speedometer/Odometer Is Inoperative - Ford Mustang 2005 Workshop Manual

2005 Mustang Workshop Manual
The low fuel indicator is on when the fuel level reaches a predetermined level of approximately 1/16 tank. The low fuel level warning indicator and the fuel gauge are controlled by the
instrument cluster based upon the fuel level data provided by the fuel pump sender and the remote fuel sender. When the instrument cluster receives the data, the fuel gauge indicates
low fuel and the instrument cluster illuminates the low fuel warning indicator.
Possible Causes
instrument cluster

PINPOINT TEST F: THE LOW FUEL WARNING INDICATOR IS NEVER/ALWAYS ON

F1 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 low fuel warning indicator.
Does the low fuel warning indicator illuminate when triggered on and turn off when
triggered off?
F2 CHECK THE FUEL GAUGE
Ignition ON.
Check the fuel gauge.
Does the fuel gauge operate correctly?
F3 CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION
Disconnect all the instrument cluster connectors.
Check for:
corrosion
pushed-out pins
Connect all the instrument cluster connectors and make sure they seat correctly.
Operate the system and verify the concern is still present.
Is the concern still present?

Pinpoint Test G: The Speedometer/Odometer Is Inoperative

Normal Operation
Vehicle speed information is sent to the instrument cluster by the powertrain control module (PCM) over the high speed controller area network (HS-CAN) communication bus. The PCM
calculates vehicle speed from the transmission output shaft speed (OSS) sensor input and from the tire size and axle ratio configuration in the vehicle identification (VID) block of the
PCM.
The instrument cluster receives an odometer message from the PCM and stores the mileage in memory. When the instrument cluster fails to receive the odometer message for more than
2 seconds, the odometer displays dashes.
Possible Causes
PCM
instrument cluster
PINPOINT TEST G: THE SPEEDOMETER/ODOMETER IS INOPERATIVE
G1 RETRIEVE THE RECORDED DTCs FROM BOTH THE CONTINUOUS AND ON-DEMAND PCM SELF-TESTS
Check for recorded PCM DTCs from the continuous and on-demand self-tests.
Are any PCM DTCs recorded?
G2 RETRIEVE THE RECORDED INSTRUMENT CLUSTER DTCs FROM BOTH THE CONTINUOUS AND ON-
DEMAND SELF-TESTS
Check the recorded instrument cluster DTCs from the continuous and on-demand self-test.
Are any instrument cluster DTCs recorded?
G3 MONITOR THE MESSAGE CENTER CIRCUIT DISPLAYS
Enter the following diagnostic mode on the scan tool: Instrument Cluster DataLogger.
Select the all segments (SEGMENTS) active command and command the segments on while monitoring the
message center display.
Do the message center display segments illuminate correctly?
G4 CHECK FOR CORRUPTED NON-VOLATILE MEMORY (NVM)
Ignition ON.
Observe the message center display area.
Does the odometer display ERROR?
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Test Step
Test Step
Result / Action to Take
Yes
GO to F2.
No
GO to F3.
Yes
GO to F3.
No
GO to Pinpoint Test B to continue diagnosis of the fuel gauge.
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
REFER to the Powertrain Control/Emissions
Diagnosis (PC/ED) manual.
No
GO to G2.
Yes
REFER to Instrument Cluster Diagnostic Trouble
Code (DTC) Index in this section.
No
For an inoperative speedometer, GO to G5.
For an inoperative odometer, GO to G3.
Yes
GO to G4.
No
GO to G7.
Yes
GO to G7.
No
GO to G6.
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Instrument Cluster (IC) in
11/14/2009