What Does C1288 Mean?
The main (primary) brake pressure transducer input circuit has failed. This sensor measures hydraulic pressure in the primary brake circuit (usually front brakes) and provides real-time brake pressure data to the ABS/ESC module. The module uses this information for brake assist, stability control pressure modulation, and diagnostic purposes. Without this input, advanced braking features may be degraded.
Common Causes
35%
Failed primary brake pressure transducer (internal circuit open or short)
25%
Wiring harness fault between the transducer and the EBCM (open, short, or high resistance)
20%
Corroded or contaminated connector at the pressure transducer
10%
Loss of 5V reference supply to the transducer from the EBCM
10%
EBCM internal A/D converter fault on the primary pressure input
Diagnostic Steps
1
Monitor the primary brake pressure PID in live data — with no brake applied, it should read near 0 PSI. Press the brake pedal progressively and watch for a smooth, proportional increase. An erratic, frozen, or missing reading confirms the circuit failure.
2
Check for 5V reference and ground at the pressure transducer connector (located on or near the master cylinder/HCU). Missing reference voltage points to a shared 5V supply issue or EBCM fault.
3
Measure the transducer signal wire voltage with the ignition on — at rest it should be approximately 0.5V, rising to 4.5V under maximum pedal pressure. Fixed at 0V or 5V indicates an open or shorted sensor.
4
Inspect the connector and wiring to the transducer for brake fluid contamination, corrosion, or chafing. Brake fluid is corrosive to wiring insulation and can wick into connectors.
5
If the transducer checks are normal, back-probe the EBCM connector at the pressure input pin and compare the reading to the transducer output — a discrepancy indicates a wiring fault between the two points.
Estimated Repair Cost
$150 - $700
Parts + labor, varies by vehicle and location
The main (primary) brake pressure transducer input circuit has failed. This sensor measures hydraulic pressure in the primary brake circuit (usually front brakes) and provides real-time brake pressure data to the ABS/ESC module. The module uses this information for brake assist, stability control pr...
The most common cause of C1288 (Pressure Transducer Main / Primary Input Circuit Failure) is: Failed primary brake pressure transducer (internal circuit open or short)
Typical repair costs for C1288 range from $150 to $700, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Standard braking functions normally, as this is a monitoring sensor not a control actuator. However, Brake Assist, advanced ESC pressure modulation, and brake pressure-based diagnostics will be impaired. The vehicle is safe for careful driving, but maximum braking efficiency in emergencies may be somewhat reduced. Schedule repair soon.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1288 to identify the root cause.
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Quick Info
Category
Chassis
System
ABS / Brake Assist
Difficulty
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