C0020

Code

LAND ROVER C — Chassis

ABS pump motor control

Brand: LAND ROVER

Type: C — Chassis

Views: UK: 36 EN: 97 RU: 69

AI status

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Page language: EN

Causes

Blown fuse or tripped circuit breaker for ABS pump power
Faulty pump motor (worn brushes, seized rotor or internal short)
Failed pump motor relay or external switch
Open, shorted or high-resistance wiring between ABS module and pump motor
Poor or corroded ground at pump motor or module
Failed motor driver circuitry inside the ABS control module

Symptoms

ABS and/or traction/stability warning lamp illuminated
ABS/ESC functions disabled or unavailable
Pump motor does not run when ABS is commanded (no noise)
Pump motor runs continuously or intermittently without command
Audible whining, grinding or unusual noise from hydraulic pump
Brake pedal behavior may feel different during ABS events; increased stopping distance under emergency braking

What to check

Read stored ABS/ESC codes with a capable scan tool; record freeze-frame and any related codes
Visually inspect ABS pump electrical connector(s) for corrosion, bent pins or water intrusion
Check fuses and relays for the ABS pump circuit (replace if faulty)
Measure battery voltage and battery terminal condition (clean/tighten if needed)
With ignition on, backprobe the pump power and ground pins to verify supply voltage and ground presence
Command the pump ON with a scan tool while monitoring voltage and current at the pump

Signal parameters

Battery supply to pump: nominal ~12 V (11–14 V range acceptable during tests)
Motor winding resistance (typical): low ohms range — often ~1–5 Ω (measure with battery disconnected)
Motor current draw when running: expected high amps (commonly several amps to tens of amps); excessive current indicates mechanical seizure, very low/no current indicates open circuit or driver fault
Control method: relay or low-side MOSFET driver from ABS module; module may use PWM to control motor speed
When commanded ON by scan tool: voltage at pump power pin ≈ battery voltage; ground pin should show low resistance to chassis
No command: pump power pin typically 0 V (or switched open) — some systems may show battery feed through a relay

Diagnostic algorithm

Retrieve and record all ABS/ESC codes and live data with a diagnostic scanner; clear codes and attempt to re-create C0020 to confirm persistence.
Visually inspect pump, harness and connectors for damage, corrosion or water entry. Repair or replace damaged connectors as needed.
Check and verify fuses and pump relay operation. Replace suspect fuse/relay and retest.
With ignition OFF, disconnect pump connector and measure motor winding resistance across motor pins. Compare to expected range. Very high (open) or very low (short) indicates motor fault.
With battery connected and using appropriate safety measures, backprobe the pump connector. Command the pump ON with the scan tool. Verify battery voltage at the power pin and a solid ground at the ground pin; monitor current draw. If voltage present but no motor current, suspect internal motor/brush failure or module driver fault.
If no supply voltage at the pump when commanded, trace wiring for open/short, check relay coil/supply and control circuit from ABS module. Use wiring diagrams for pin identification and continuity testing.
Check chassis/engine ground continuity from pump ground to battery negative; clean and secure grounds as necessary.
If wiring, power and ground are good and the motor still does not operate when commanded, consider bench-testing or replacing the pump assembly, or refer to module diagnostics to test/replace ABS module motor driver.
After repairs, clear codes and perform a road test/ABS activation test to verify the fault does not return. Re-scan for any residual or related codes.

Likely causes

Blown fuse or faulty relay supplying the pump (easy to check)
Open/short in the pump power or ground circuit (common)
Seized or electrically failed pump motor (medium probability on high-mileage vehicles)
Faulty ABS module motor driver (less common but possible)
Poor ground or corroded connector causing intermittent operation

Fault status

⚠️ Status

ABS pump motor control fault detected — check pump power/ground, relay and wiring. ABS/ESC functionality may be reduced or disabled until fault is corrected.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1-3 hours

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C0020 — ABS pump motor control