C2198

Code

Generic C — Chassis

Brake Pressure Sensor Circuit Range/Performance

Brand: Generic

Type: C — Chassis

Views: UK: 9 EN: 13 RU: 6

AI status

Completed

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Page language: EN

Causes

Faulty brake pressure sensor (internal failure)
Damaged, corroded or disconnected wiring/connector between sensor and ABS/ESC module
Poor or missing sensor reference voltage or ground
Hydraulic issue (leak, stuck valve, internal modulator fault) giving unexpected pressure behavior
Faulty ABS/ESC control module or software/calibration error
Low brake fluid level or contaminated fluid affecting sensor reading

Symptoms

ABS, ESC or Brake warning lamp illuminated
Traction control and/or cruise control disabled
Reduced or no ABS function during braking
Unusual brake pedal feel (spongy or inconsistent) under ABS events
Stored and/or intermittent additional ABS-related fault codes

What to check

Read and record all stored codes, freeze frame and live data with a capable scan tool
Visual inspection of sensor connector, wiring harness and ABS module connectors for corrosion, damage or water intrusion
Check brake fluid level and condition; inspect brake lines and calipers for leaks
Backprobe sensor connector and verify reference voltage, signal voltage and ground at key pedal positions
Compare live brake pressure sensor data to expected values while operating pedal or using a pressure gauge
Wiggle-test wiring while monitoring live data to reveal intermittent opens/shorts

Signal parameters

Typical sensor type: analog pressure sender (voltage output) or CAN/serial message to ABS module
Common analog expected range: ~0.5–4.5 V (varies by vehicle); signal should rise smoothly with increased brake pressure
Reference supply typically 5 V and a dedicated ground — verify stable reference under load
Live-data should change with pedal travel or applied hydraulic pressure; no sudden drops/spikes or flat-line signals

Diagnostic algorithm

Connect a professional scan tool. Read and save all codes, freeze frame and live brake pressure sensor data. 2) Visually inspect sensor connector, harness and mounting. Repair damaged connectors or harness sections. 3) Check brake fluid level and inspect for leaks. Address any hydraulic leaks before electrical replacement. 4) With ignition on, backprobe sensor connector: verify reference voltage (~5 V), good ground and that signal voltage moves smoothly when pedal is pressed. If reference/ground missing, trace to ABS module and repair. 5) If electrical supply and ground are good but signal is out of expected range or inconsistent, measure sensor output while applying pressure with a calibrated pressure gauge to confirm sensor accuracy. 6) Wiggle harness and connectors while monitoring live data to find intermittent faults. 7) If wiring and supply are good and sensor output is incorrect, replace brake pressure sensor and retest. 8) After repairs, clear codes, perform ABS bleed/calibration or module relearn if required by manufacturer, then road-test to confirm proper operation. 9) If fault persists after sensor replacement and wiring verified, evaluate ABS/ESC control module for internal faults or update module software and consult wiring schematics for further bench testing.

Likely causes

Sensor electrical failure (most common)
Open/shorted connector or chafed harness at steering column/ABS module
Poor ground or 5V reference missing at sensor
ABS hydraulic modulator valve internal fault affecting measured pressure
Module communication fault or intermittent connector

Fault status

⚠️ Status

Brake pressure sensor circuit range/performance fault detected. ABS/ESC may be disabled; inspect sensor, wiring and ABS module. Live-data shows out-of-range or inconsistent brake pressure signal.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours