Pinpoint Test C: Incorrect Temperature Gauge Indication
Normal Operation
Normal engine operating temperature is 60°C (140°F) to 120°C (248°F). The engine coolant temperature (ECT) sensor unit monitors the coolant temperature and is hardwired directly to
the powertrain control module (PCM). The status of the engine coolant temperature is sent from the PCM to the instrument cluster over the communication network.
Possible Causes
PCM
instrument cluster
PINPOINT TEST C: INCORRECT TEMPERATURE GAUGE INDICATION
Does the resistance of both senders start at approximately 15 ohms with the float at the bottom
of the travel and slowly increase to approximately 160 ohms with the float at the top of the
travel?
B21 CHECK THE FUEL LEVEL SENDER
NOTE: The fuel level sender resistance will measure between 15 ohms ± 2 ohms at the lower stop
position and 160 ohms ± 4 ohms at the upper stop position.
Remove the fuel pump module. Refer to Section 310-01.
NOTE: Disconnect the fuel level sender input wire from the fuel level sender for this measurement.
Measure the resistance between the fuel level sender input wire and the fuel level sender ground
while slowly moving the float arm between the lower stop and the upper stop position.
Does the resistance slowly increase from approximately 15 ohms to 160 ohms?
Yes
INSTALL a new fuel pump module. REFER to Section 310-01.
TEST the system for normal operation.
No
INSTALL a new fuel level sender. REFER to Section 310-01.
TEST the system for normal operation.
B22 CHECK FOR CORRECT SJB OPERATION
Disconnect all the SJB connectors.
Check for:
corrosion
damaged pins
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?
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.
B23 CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION
Disconnect the instrument cluster connector.
Check for:
corrosion
damaged pins
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?
Yes
INSTALL a new instrument cluster. REFER to Instrument Cluster
(IC) in 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. CLEAR the
DTCs. REPEAT the self-test.
Test Step Result / Action to Take
C1 CARRY OUT THE INSTRUMENT CLUSTER COOLANT TEMPERATURE GAUGE 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 temperature gauge active command. Trigger the temperature
gauge active command. Scroll in 2 increments of 0%, and 100%.
Does the temperature gauge start at C (cold) when at 0%, and move to H (hot) at 100%?
Yes
GO to C3.
No
GO to C2.
C2 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?
Yes
INSTALL a new instrument cluster. REFER to Instrument Cluster (IC) in
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.
C3 CHECK FOR CORRECT POWERTRAIN CONTROL MODULE (PCM) OPERATION
Disconnect all the PCM connectors.
Check for:
Yes
INSTALL a new PCM. REFER to Section 303-14. TEST the system for
normal operation.
2005 Mustang Workshop Manual
http://www.fordtechservice.dealerconnection.com/pubs/content/
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