C1440
Pressure Transducer Input Circuit Failure
YES
C1440 (ABS only)
Pressure Transducer Input Circuit Failure
ABS Module
Go To Pinpoint Test P .
Normal Operation
The brake pressure switch provides an additional speed control deactivation if the brake pedal position (BPP) switch fails. When the brake pedal is pressed, 1700 kPa (246 psi) of brake fluid pressure in the brake master cylinder opens the brake pressure switch, removing B+ voltage to the speed control servo electric clutch.
Possible Causes
PINPOINT TEST P: DTC C1440 (ABS ONLY) - PRESSURE TRANSDUCER SIGNAL FAULT
CAUTION: Use the flex probe kit for all test connections to prevent damage to the wiring terminals. Do not use standard multimeter probes.
Test Step
Result / Action to Take
P1 VERIFY THE DTC
Yes
GO to P2 .
No
The system is OK at this time.
P2 MONITOR THE BRAKE PRESSURE SWITCH PID FOR CLOSED POSITION
Yes
GO to P3 .
No
GO to P4 .
P3 MONITOR THE BRAKE PRESSURE SWITCH PID FOR OPEN POSITION
Yes
GO to P9
No
GO to P7 .
P4 CHECK THE CIRCUIT 10 (LG/RD) FOR AN OPEN
Yes
GO to P5 .
No
REPAIR the circuit. CLEAR the DTCs and REPEAT the self-test.
P5 CHECK THE BRAKE PRESSURE SWITCH
Yes
GO to P6 .
No
INSTALL a new speed control deactivator switch. REFER to Section 310-03 . CLEAR the DTCs. REPEAT the self-test.
P6 CHECK CIRCUIT 307 (BK/YE) FOR AN OPEN
Yes
GO to P9
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
P7 CHECK CIRCUIT 307 (BK/YE) FOR A SHORT TO POWER
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
No
GO to P8 .
P8 CHECK BRAKE PRESSURE SWITCH
Yes
GO to P9 .
No
INSTALL a new speed control deactivator switch. REFER to Section 310-03 . CLEAR the DTCs. REPEAT the self-test.
P9 CHECK FOR CORRECT ABS MODULE OPERATION
Yes
INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module in this section. TEST the system for normal operation.
No
The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
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