Ford Electric Ranger 2001 Manual page 153

206-07-4
DIAGNOSIS AND TESTING (Continued)
Symptom Chart (Continued)
Condition
• Vacuum Pump Exhibits
Unusual or Excessive Noise
Pinpoint Tests
Special Tool(s)
104-Pin Breakout Box (BOB) 418-049 (014-00950) or
equivalent
PINPOINT TEST A: DTC C1777 VACUUM PRESSURE CIRCUIT FAILURE
A1 IDENTIFY SYMPTOM
• With key ON, depress the brake pedal.
NOTE: DTC C1777 is set if the vacuum pump does not operate, runs
continuously without cycling on and off, or cycles on and off without brake
pedal or climate control activation.
• Identify the symptom of the vacuum system operation.
• Does the vacuum pump operate?
A2 CHECK VACUUM PUMP OPERATION
• Enter the interface adapter assembly (IAA) module active command mode
THERMAL REGULATION OUTPUT CONTROL and set the active
command VAC RLY to ON.
• Does the vacuum pump operate?
A3 CHECK INTERFACE ADAPTER ASSEMBLY (IAA) MODULE
• With key OFF, disconnect vacuum pressure sensor C1997.
• Connect 104-Pin Breakout Box (BOB) to the IAA module and IAA module
C1945.
• With key ON, monitor the IAA module PID VACPRES.
• Connect a jumper wire between BOB pins 4 and 88.
• Does the VACPRES PID indicate greater than 80 kPa (11.6 psi)?
A4 CHECK CIRCUITS 3032 (DB/LG) AND 3033 (BK/LB) FOR OPEN(S)
• With key OFF, measure the resistance of the DB/LG wire between vacuum
pressure sensor C1997 and BOB pin 4.
• With key OFF, measure the resistance of the BK/LB wire between vacuum
pressure sensor C1997 and BOB pin 88.
• Are the resistances less than 5 ohms?
A5 CHECK CIRCUITS 3032 (DB/LG) AND 3033 (BK/LB) FOR SHORT(S)
TO GROUND
• With key OFF, disconnect the IAA module from the BOB; leave BOB
connected to IAA module C1945.
• With key OFF, measure the resistance between BOB pins 4, 88 and ground.
• Are the resistances greater than 10,000 ohms?
A6 CHECK FUSE AND POWER TO VACUUM PUMP RELAY
• With key OFF, check 20A fuse 13 in the electric vehicle power distribution
box (EVPDB).
(Continued)
Power Brake Actuation
Possible Sources
• Vacuum pump.
• Incorrect vacuum pump
bracket bolt torque
specifications.
• Incorrect vacuum pump
installation.
TEST STEP
Action
• GO to
Pinpoint Test D.
ACTION TO TAKE
Yes GO to A12.
=
No = GO to A2.
Yes GO to A3.
=
No = GO to A6.
Yes GO to A4.
=
No = REPLACE the IAA module.
REFER to Section
Yes GO to A5.
=
No = REPAIR the wire(s) in
question.
Yes REPLACE the vacuum
= pressure sensor.
No = REPAIR the wire(s) in
question.
Yes RECONNECT the vacuum
= pump relay. GO to A7.
2001 Ranger EV, 01/2001
206-07-4
412-04.