C1476 — ABS Pump Supply Plausibility Fault

C1476 — ABS Pump Supply Plausibility Fault. C1476 identifies an implausible relationship between ABS pump supply and the measured delivery level.

For Ford vehicles

plausibility between brake system pump supply volume and sensor signal indicating a delivery level which is too low for master cylinder piston travel and master cylinder volume

vehicle

Is it safe to drive?

Prompt ABS service recommended C1476 identifies an implausible relationship between ABS pump supply and the measured delivery level. Base braking may remain functional, but ABS control and normal hydraulic assist may be impaired. Arrange diagnosis promptly, and stop driving if the pedal becomes soft, the fluid level falls, or braking performance changes.

Typical symptoms

C1476 is stored in the ABS control module
ABS warning lamp illuminates
Brake pedal feels unusually soft, firm, or requires more travel
ABS assistance does not operate normally during a braking event
Brake-fluid level may be low or may change without an obvious external leak
The fault may appear only during pressure buildup or active ABS operation

Common causes

Low brake fluid level or air entrapment starving the ABS hydraulic pump
Restricted brake-fluid passage between the reservoir, ABS pump, and master cylinder
Weak or electrically unloaded ABS pump motor unable to supply the required fluid volume
Faulty pump-motor relay, fuse, connector, wiring, or ground connection
Drifted or inaccurate brake-pressure or delivery-level sensor signal
Internal ABS hydraulic-valve leakage or an intermittent pump fault
Worn master cylinder or a hydraulic leak reducing the available delivery level

How to diagnose with an OBD scanner

Inspect the brake-fluid supply With the vehicle cold and on level ground, check the brake-fluid reservoir and ABS reservoir for correct level, contamination, or aeration. Inspect the reservoir, master cylinder, lines, and hydraulic connections for leaks. Do not open a hot reservoir because pressurized brake fluid can escape.
Read ABS data with a scanner Connect an OBD scanner such as ELM327 or AIScanAuto, select the ABS module if supported, and confirm C1476. Review live pump-command, pump-current, and brake-pressure or delivery-level data while the ABS pump builds pressure. An inexpensive ELM327 adapter may provide only limited ABS information, so a vehicle-specific scanner may be required.
Check pump electrical operation Inspect the ABS pump fuse, relay, connectors, wiring, and ground. Listen for pump-motor operation during an ABS bleed or pressure-build command and compare the result with scan data. Follow vehicle wiring diagrams rather than assuming a particular fuse location.
Perform hydraulic checks If the pump receives power but does not build the expected delivery level, check for restricted supply passages, trapped air, valve leakage, and master-cylinder or line restrictions. Pressure and flow testing should be performed before replacing the ABS module.
Repair and verify C1476 Correct the confirmed fluid, electrical, sensor, or hydraulic fault, bleed the system properly, and verify firm pedal operation. Clear C1476 with the scanner, road-test the vehicle, and rescan to confirm that the plausibility fault does not return.

Approximate repair cost

An independent shop may charge roughly $150-$900 for C1476 diagnosis and repair, depending on whether the cause is fluid service, wiring, a sensor, a pump, or more extensive hydraulic work. These USD figures are estimates only and vary by region, vehicle, and parts availability.

Common questions

What does C1476 mean specifically?

C1476 means the ABS module found an implausible difference between brake-pump supply volume and the delivery-level or pressure signal needed for master-cylinder piston travel.

Can I drive with C1476 stored?

Drive cautiously to a repair facility only if ordinary braking remains firm and stable, the fluid level is correct, and there are no leaks. Do not continue if the pedal is soft, unusually hard, or the fluid level is dropping.

Will an ELM327 scanner diagnose C1476?

ELM327 can often confirm C1476, but it may not display the pump-command and pressure-plausibility data needed for diagnosis. A scanner with access to the vehicle's ABS live-data functions may be necessary.

Does C1476 require ABS module replacement?

Not necessarily. Low fluid, trapped air, wiring, a relay, a sensor, pump wear, or hydraulic restrictions should be tested first; module replacement should be considered only after those checks.

C1476 — C1476 — Manufacturer Controlled DTC: Causes, Symptoms & Fix

C1476 is a manufacturer-controlled diagnostic trouble code that indicates the vehicle's control module has detected abnormal behavior within a specific sensor or actuator circuit. Unlike universal OBD2 codes that follow SAE standards, C1476 is defined by the vehicle manufacturer, meaning the exact component and circuit vary by make and model. When the powertrain control module (PCM) or body control module runs its self-diagnostics, it monitors voltage, resistance, and signal patterns from various circuits. When readings fall outside expected parameters repeatedly under specific driving conditions, the module logs C1476 and illuminates the check engine light.

The freeze frame data stored alongside the code is particularly valuable—it captures engine load, RPM, coolant temperature, vehicle speed, and other sensor readings at the moment the fault occurred. This snapshot essentially freezes time, allowing you to recreate those exact conditions during diagnosis. The system works by continuously comparing real-time sensor data against factory-defined thresholds; when the pattern matches a known failure mode, the ECU triggers the code and disables or limits the affected function.

Common Symptoms of C1476

The system related to the fault code operates intermittently or stops working entirely
The vehicle may enter a reduced-power limp mode, limiting performance and functionality
Fuel economy can degrade noticeably in certain cases
The check engine light or warning indicator stays illuminated on the dashboard
The affected component—such as a valve, sensor, or actuator—may produce unusual sounds or fail to respond
Depending on which circuit is involved, other systems like traction control or emissions controls may be impacted

Common Causes of C1476

Damaged, corroded, or disconnected wiring within the affected circuit
A blown fuse or power supply issue feeding the component
A failed sensor or actuator that no longer operates within specifications
Poor ground connection at the component or control module
Moisture intrusion into connectors causing short circuits or signal degradation
A faulty control module unable to process signals correctly
Software glitch requiring a refl ash or update from the manufacturer

How to Diagnose C1476

Connect an OBD2 scanner and confirm C1476 is stored in the module's memory. Save the freeze frame data immediately—this data reveals the exact engine conditions (load, temperature, speed) when the fault occurred.
Look for any related diagnostic trouble codes. When multiple codes appear, they often point to the root cause rather than the symptom. Check for manufacturer technical service bulletins (TSB) using your VIN—many C0xxx codes have documented factory fixes or software updates.
Perform a thorough visual inspection of the wiring harness and connectors tied to C1476. Look for damaged insulation, broken wires, pushed-out pins, corrosion buildup, or loose connections that could interrupt signal flow.
Use a multimeter to measure reference voltage, ground integrity, and signal continuity at the component connector. Compare your readings against manufacturer specifications.
Conduct a wiggle test on the harness while monitoring live data on your scan tool. Any signal dropouts or fluctuations indicate broken wires inside the insulation that aren't visible on the surface.
Clear the code, then drive the vehicle through a complete drive cycle—including the specific conditions recorded in the freeze frame—to verify C1476 does not return. If the code reappears, you have confirmed an active fault.

Repair Options and Costs

Start with the cheapest and most common repairs before moving to expensive component replacement:

Wiring or connector repair — typically $80–$250 for parts and labor
Faulty sensor or actuator replacement — typically $150–$500 depending on the specific component
Control module diagnosis and repair — typically $300–$1,000 depending on whether the module can be repaired or must be replaced

How Much Does It Cost to Fix C1476?

Total repair cost for C1476 depends entirely on which component is actually at fault. Independent shop labor rates typically range from $80–$150 per hour. The most common scenario—a wiring issue—costs $80–$250. Replacing a failed sensor or actuator usually runs $150–$500 including labor. Control module diagnosis and repair is the most expensive option at $300–$1,000. Overall, expect to pay between $80 and $1,000 to resolve C1476. The key is getting an accurate diagnosis before purchasing parts—the most expensive repair is rarely where you should start.

Can You Drive with C1476?

In most cases, the vehicle remains drivable when C1476 is present, though you may experience reduced performance or a disabled auxiliary system. However, if the malfunction causes stalling, prevents the engine from starting, or triggers warnings related to braking or steering, treat it as urgent and seek immediate repair. Otherwise, schedule diagnosis and repair at your earliest convenience before symptoms worsen.