Ford 2001 Ranger, Manual

Page: 153 / 1218

206-07-4 206-07-4 Power Brake Actuation
DIAGNOSIS AND TESTING (Continued)
Symptom Chart (Continued)
Condition Possible Sources Action
•
Vacuum Pump Exhibits
•
Vacuum pump.
•
GO to Pinpoint Test D.
Unusual or Excessive Noise • Incorrect vacuum pump
bracket bolt torque
specifications.
•
Incorrect vacuum pump
installation.
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
TEST STEP ACTION TO TAKE
A1 IDENTIFY SYMPTOM
•
With key ON, depress the brake pedal. Yes GO to A12.
=
NOTE: DTC C1777 is set if the vacuum pump does not operate, runs
No = GO to A2.
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 Yes GO to A3.
THERMAL REGULATION OUTPUT CONTROL and set the active =
command VAC RLY to ON.
•
Does the vacuum pump operate? No = GO to A6.
A3 CHECK INTERFACE ADAPTER ASSEMBLY (IAA) MODULE
•
With key OFF, disconnect vacuum pressure sensor C1997. Yes GO to A4.
=
•
Connect 104-Pin Breakout Box (BOB) to the IAA module and IAA module No = REPLACE the IAA module.
C1945. REFER to Section 412-04 .
•
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 Yes GO to A5.
pressure sensor C1997 and BOB pin 4. =
•
With key OFF, measure the resistance of the BK/LB wire between vacuum No = REPAIR the wire(s) in
pressure sensor C1997 and BOB pin 88. question.
•
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 Yes REPLACE the vacuum
connected to IAA module C1945. = pressure sensor.
• With key OFF, measure the resistance between BOB pins 4, 88 and ground. No = REPAIR the wire(s) in
•
Are the resistances greater than 10,000 ohms? question.
A6 CHECK FUSE AND POWER TO VACUUM PUMP RELAY
•
With key OFF, check 20A fuse 13 in the electric vehicle power distribution Yes RECONNECT the vacuum
box (EVPDB). = pump relay. GO to A7.
(Continued)
2001 Ranger EV, 01/2001