Monitor GEM PIDs IGN_KEY, IGN_S, IGN_R, and IGN_A while cycling the ignition switch through all
positions and then removing the key from ignition switch.
Do the PIDs agree with the ignition switch status?
Yes
GO to
L2
.
No
REFER to
Section 211-05
. CLEAR the DTCs. REPEAT the self-test.
L2
DETERMINE IF GEM IS RECEIVING THE CORRECT PARKING BRAKE INPUT
Monitor GEM PID PRK_BRK while applying and releasing the parking brake.
Did the PID read ON with the parking brake applied, and OFF with the parking brake released?
Yes
GO to
L3
.
No
GO to
L5
.
L3
DETERMINE IF BRAKE WARNING INDICATOR CIRCUIT IS OPEN OR GROUNDED
Verify that the parking brake is released.
Is the instrument cluster BRAKE warning indicator off?
Yes
GO to
L4
.
No
GO to
L10
.
L4
DETERMINE IF GEM IS SENDING THE CORRECT OUTPUT SIGNAL
Trigger the GEM active command BKFLD LOW.
Did the instrument cluster BRAKE warning indicator illuminate?
Yes
INSTALL a new GEM; REFER to
Section 419-10
. CLEAR the DTCs. REPEAT the self-test.
No
GO to
L8
.
L5
CHECK CIRCUIT BETWEEN THE PARKING BRAKE SWITCH AND THE GEM FOR A SHORT TO GROUND
Monitor PID PRK_BRK while applying and releasing the parking brake.
Did the PID read ON with the parking brake applied and with the parking brake released?
Yes
GO to
L7
.
No
GO to
L6
.
L6
CHECK FOR AN OPEN BETWEEN THE PARKING BRAKE SWITCH AND THE GEM
Parking Brake Switch C318
GEM C293
Measure the resistance between the GEM C293 Pin 4, Circuit 128 (VT/YE), harness side and parking brake
switch C318, Circuit 22 (LB/BK), harness side.
Page 22 of 32
1999 Mustang Workshop Manual
1/18/2013
http://www.fordtechservice.dealerconnection.com/pubs/content/~WSXB/~MUS~LEN/20/...
