What Does C1440 Mean?
This code signals that the primary brake pressure transducer is sending a faulted signal to the ABS/stability control module. The pressure transducer converts hydraulic brake line pressure into an electrical signal used for brake assist calibration and stability control calculations. A faulted primary signal means the module cannot accurately determine how much brake force the driver is applying, which compromises electronic brake distribution and stability control functionality.
Safety Warning
Without accurate brake pressure data, the stability control and electronic brake distribution systems cannot function correctly. Emergency braking performance may be degraded, and the vehicle may lose stability control intervention during panic stops.
Common Causes
40%
Failed primary brake pressure transducer with internal diaphragm or strain gauge damage
25%
Corroded or water-damaged connector at the pressure transducer, causing signal dropout or noise
20%
Wiring harness damage between the transducer and ABS module, particularly near the master cylinder area where brake fluid exposure is possible
15%
ABS hydraulic control unit internal fault affecting transducer signal processing
Diagnostic Steps
1
Step 1: Locate the primary brake pressure transducer on the ABS hydraulic control unit or brake master cylinder assembly. Inspect the connector for brake fluid contamination, corrosion, or damaged terminals. Brake fluid is hygroscopic and causes severe corrosion when it contacts electrical terminals.
2
Step 2: With ignition on, measure the pressure transducer signal voltage at the ABS module connector. At rest (no pedal applied), expect approximately 0.5V. Apply moderate brake pressure and verify the voltage rises linearly to approximately 2.5-3.5V.
3
Step 3: Verify the 5V reference supply and ground at the transducer connector. Check for voltage drop on the ground circuit (should be less than 50mV to chassis ground).
4
Step 4: Compare the primary transducer reading against the secondary/redundant transducer (if equipped) using live data. A significant deviation between the two confirms a faulty primary transducer.
5
Step 5: If the transducer is integral to the ABS HCU and cannot be replaced separately, the entire hydraulic control unit assembly may need replacement. Verify by swapping with a known-good unit if available.
Estimated Repair Cost
$200 - $1,200
Parts + labor, varies by vehicle and location
This code signals that the primary brake pressure transducer is sending a faulted signal to the ABS/stability control module. The pressure transducer converts hydraulic brake line pressure into an electrical signal used for brake assist calibration and stability control calculations. A faulted prima...
The most common cause of C1440 (Pressure Transducer Main / Primary signal Faulted) is: Failed primary brake pressure transducer with internal diaphragm or strain gauge damage
Typical repair costs for C1440 range from $200 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Without accurate brake pressure data, the stability control and electronic brake distribution systems cannot function correctly. Emergency braking performance may be degraded, and the vehicle may lose stability control intervention during panic stops.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1440 to identify the root cause.
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Quick Info
Category
Chassis
System
ABS / Electronic Brake Distribution
Difficulty
Type
Manufacturer
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