Ford Ranger EV (2001 year). Manual - part 39
206-07-6
206-07-6
Power Brake Actuation
DIAGNOSIS AND TESTING (Continued)
PINPOINT TEST A: DTC C1777 VACUUM PRESSURE CIRCUIT FAILURE
TEST STEP
ACTION TO TAKE
•
Measure the resistance between terminals 3 and 5 on the vacuum pump
Yes
REPLACE the vacuum
relay.
=
pump relay.
•
Is the resistance less than 5 ohms?
No =
GO to A15.
A15 CHECK CIRCUIT 3021 (GY/BK) FOR SHORT TO GROUND
•
With key OFF, disconnect IAA module C1945 and measure the resistance
Yes
REPLACE the IAA module.
between pin 2 on the vacuum pump relay connector and ground.
=
•
Is the resistance greater than 10,000 ohms?
No =
REPAIR the GY/BK wire.
A16 CHECK VACUUM PRESSURE SENSOR
•
Connect 104-Pin Breakout Box (BOB) to the IAA module and IAA module
Yes
GO to A18.
C1945.
=
•
With key ON, measure the voltage between BOB pins 4 and 89.
No =
GO to A17.
•
Is the voltage greater than 4.2 volts?
A17 CHECK VACUUM PRESSURE
•
With key ON, monitor the interface adapter assembly (IAA) module PID
Yes
REPLACE the IAA module.
VACPRES.
=
•
Is the VACPRES PID greater than 80 kPa (11.6 psi)?
No =
System OK. CHECK wiring
for intermittent connections.
A18 CHECK CIRCUITS 3032 (DB/LG), 3033 (BK/LB), AND 3034 (LG/R)
FOR SHORT(S) TO POWER
•
With key OFF, disconnect the IAA module from the BOB; leave BOB
Yes
REPAIR the wire(s) in
connected to IAA module C1945.
=
question.
•
With key ON, measure the voltage between BOB pins 4, 88, 89, and
No =
GO to A19.
ground.
•
Are any of the voltages greater than 0 volts?
A19 CHECK CIRCUIT 3034 (LG/R) FOR OPEN
•
With key OFF, measure the resistance of the LG/R wire between vacuum
Yes
REPLACE the vacuum
pressure sensor C1997 and BOB pin 89.
=
pressure sensor.
•
Is the resistance less than 5 ohms?
No =
REPAIR the LG/R wire.
PINPOINT TEST B: EXCESSIVE BRAKE PEDAL EFFORT TO STOP VEHICLE
TEST STEP
ACTION TO TAKE
B1 CHECK FOR INTERFACE ADAPTER ASSEMBLY (IAA)
MODULE DIAGNOSTIC TROUBLE CODES (DTCs)
•
Retrieve DTCs from the IAA module.
Yes =
•
Does DTC C1777 Vacuum Pressure Circuit Failure occur?
No =
GO to B2.
B2 CHECK VACUUM PUMP PERFORMANCE
•
With key OFF, disconnect the vacuum hose at the vacuum pump.
Yes =
PERFORM mechanical
brake diagnostics. REFER to
Section 206-00 in the 2001
Ranger Workshop Manual.
•
Depress the brake pedal until the pedal is hard to press.
No =
REPLACE the vacuum
•
Reconnect the vacuum hose to the vacuum pump.
pump.
•
Monitor the IAA module PID VACPRES and note the time it takes the
vacuum pressure to reach 34 kPa (4.9 psi).
•
Does the vacuum pressure reach 34 kPa (4.9 psi) in less than 18
seconds?