Ford 2003 Mustang Workshop Manual page 3541

Measure the voltage between DLC C251 Pin 10,
Circuit 915 (PK/LB), harness side and C251 Pin 4,
Circuit 1205 (BK); and between DLC C251 Pin 10,
Circuit 915 (PK/LB), harness side and C251 Pin 16,
Circuit 1047 (LG/RD), harness side.
Is the voltage zero volts for any measurement?
G9 CHECK CIRCUIT 914 (TN/OG) AND CIRCUIT 915
(PK/LB) FOR THE SOURCE OF THE CONCERN — IN-LINE
C215 DISCONNECTED
Key in OFF position.
Disconnect: In-Line C215.
Key in ON position.
Measure the voltage between DLC C251 Pin 2, Circuit
914 (TN/OG), harness side and C251 Pin 4, Circuit
1205 (BK); and between DLC C251 Pin 2, Circuit 914
(TN/OG), harness side and C251 Pin 16, Circuit 1047
(LG/RD), harness side.
Measure the voltage between DLC C251 Pin 10,
Circuit 915 (PK/LB), harness side and C251 Pin 4,
Circuit 1205 (BK); and between DLC C251 Pin 10,
Circuit 915 (PK/LB), harness side and C251 Pin 16,
Circuit 1047 (LG/RD), harness side.
Yes
GO to G10 .
No
REPAIR the circuit(s) in question
between in-line C215, in -line
C144 (if equipped with the anti-
lock brake control module), and
the PCM C175. For additional
information, REFER to
Communication Circuit Wiring
Repair . TEST the system for
normal operation.