Code Definition

C1777 — Vacuum Pressure Circuit Failure

System: Chassis  |  Type: Manufacturer-Specific  |  Make: Ford

About C1777

C1777 is a manufacturer-specific chassis diagnostic trouble code recorded for Ford vehicles. It belongs to the C-prefix family of codes, which covers chassis, braking, steering, suspension, or stability-control faults.

When C1777 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

Scanning & clearing: Chassis (C) codes are stored in the ABS, traction control, or stability-control modules. An enhanced or OEM-level scan tool is usually required to read and clear them.

C1777 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

DTC C1777 is set when the control module detects a failure in the vacuum pressure circuit used to monitor brake booster vacuum. On Ford hybrid applications such as the Escape Hybrid, a vacuum pressure transducer reports booster vacuum to the ABS module so the system knows brake assist is available while the petrol engine starts and stops, and the engine or auxiliary pump can be run to restore vacuum when it falls low. The code sets when the transducer signal goes open circuit, shorts to voltage or ground, or reports values outside the expected range. When this code is set, the driver may notic...

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