C2511

Code

Generic C — Chassis

ABS Pressure Sensor Circuit — Intermittent Signal

Brand: Generic

Type: C — Chassis

Views: UK: 18 EN: 22 RU: 16

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Page language: EN

Causes

Faulty/aging ABS hydraulic pressure sensor
Loose, corroded or contaminated sensor connector
Broken, chafed, pinched or intermittent wiring in the harness
Poor power supply or ground to the sensor
Intermittent internal fault in the ABS control module
Water intrusion or debris in connector or sensor housing

Symptoms

ABS warning lamp illuminated intermittently or continuously
Traction/stability control warning or limited ABS function
Occasional unexpected ABS activation or loss of ABS assistance
Brake pedal pulsation or inconsistent brake feel during ABS events
Fault code(s) stored and possibly intermittent drivability or warning history

What to check

Read and record freeze frame and history from scan tool; verify C2511 present and whether intermittent flag set
Visually inspect sensor connector and harness for corrosion, bent pins, broken insulation, or water ingress
Wiggle-test wiring and connector while monitoring live sensor data to reproduce the intermittent behavior
Check for proper power reference and ground at sensor connector with key on (refer to vehicle-specific manual)
Backprobe and monitor sensor signal with a lab scope or multimeter while cycling the brake/ABS pump to watch for dropouts
Inspect ABS hydraulic unit and sensor mounting for mechanical damage and contamination

Signal parameters

Expected sensor output: analog voltage proportional to hydraulic pressure (typical range ~0.5–4.5 V depending on vehicle)
Reference/power supply to sensor usually switched +5 V or vehicle battery voltage—verify with service data
Low-frequency dropouts or abrupt voltage jumps indicate intermittent connection or internal sensor fault
When healthy, signal should change smoothly with pressure and remain stable when pressure steady
Open circuit shows infinite resistance; intermittent short to ground or battery will show abrupt voltage changes

Diagnostic algorithm

Connect appropriate scan tool and verify stored C2511, freeze frame and live data for ABS pressure sensor
Clear codes and attempt to reproduce fault while monitoring live sensor voltage and ABS pump activation
Visually inspect sensor connector and harness; disconnect, inspect pins, clean with electrical contact cleaner, and reconnect securely
Backprobe sensor power, ground, and signal terminals with key on and while operating brake/ABS pump; compare to expected voltages from service data
Perform wiggle test along harness and at suspension/engine movement points while monitoring signal for interruptions
Use an oscilloscope to observe waveform for dropouts or noise if available; use a multimeter for DC checks if scope not available
If intermittent persists and wiring and connector are good, swap or bench-test sensor (if replacement sensor bench test available) or replace sensor and retest
If new sensor and wiring checks do not clear intermittent, inspect/repair wiring to ABS module and verify module power/grounds; consider module fault if all else checks good
After repairs, clear codes, perform road test with scan tool connected to confirm no recurrence and proper ABS operation

Likely causes

Corroded or loose sensor connector at hydraulic unit
Broken/chafed wire causing intermittent open/short when engine/between bumps
Sensor internal intermittent failure due to heat or moisture
Poor ground or low reference voltage from ABS module
ABS hydraulic unit wiring damaged during service

Fault status

⚠️ Status

Intermittent ABS pressure sensor circuit signal detected by ABS control module. Fault recorded; intermittent condition may cause ABS/traction warnings.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.5 - 3 hours