Ford 2003 Mustang Workshop Manual page 3557

The anti-theft system
does not operate
correctly — the
vehicle starts but
flashes a fault code
on the theft indicator
at key on
Pinpoint Tests
PINPOINT TEST A: NO COMMUNICATION WITH THE INSTRUMENT
CLUSTER
A1 CHECK THE BATTERY POWER SUPPLY TO THE
INSTRUMENT CLUSTER
Key in OFF position.
Disconnect: Instrument Cluster C220b.
Measure voltage between instrument cluster C220b Pin 10,
Circuit 729 (RD/WH), harness side and ground.
Is the voltage greater than 10 volts?
A2 CHECK THE RUN POWER SUPPLY TO THE INSTRUMENT
CLUSTER
Key in ON position.
Measure the voltage between instrument cluster C220b Pin 11,
Circuit 489 (PK/BK), harness side and ground.
Is the voltage greater than 10 volts?
A3 CHECK RUN/START POWER SUPPLY TO THE INSTRUMENT
Incorrect PCM
calibration
Test Step
DTCs are retrieved,
CHECK for other
possible causes.
GO to Pinpoint Test C .
Result / Action to Take
Yes
GO to A2 .
No
REPAIR the circuit.
REPEAT the self-test.
CLEAR the DTCs.
Yes
GO to A3 .
No
REPAIR the circuit.
REPEAT the self-test.
CLEAR the DTCs.