C1330

Code

Generic C — Chassis

ABS Pump Motor Relay Circuit Malfunction

Brand: Generic

Type: C — Chassis

Views: UK: 16 EN: 21 RU: 15

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Page language: EN

Causes

Blown fuse for ABS pump/relay circuit
Faulty ABS pump motor relay (stuck open/closed or intermittent)
Open or shorted wiring between ABS module, relay, and pump motor
Poor or corroded connector pins at relay, pump motor, or ABS module
Failed ABS pump motor
Bad ground (chassis or module ground)

Symptoms

ABS warning lamp illuminated
Possible traction control or ESC warning lamp
ABS operation unavailable (no ABS activation during test)
ABS pump may run continuously or not at all
Unusual noise from pump if relay is sticking
Brake pedal feel usually normal for normal braking (ABS disabled)

What to check

Visual inspection of relay, fuse, ABS pump, and associated connectors for corrosion, water ingress, or damage
Check main battery voltage (key on) — should be ~11.5–14.5 V
Verify ABS fuse and relay presence and rating; inspect fuse for blown condition
Use a scan tool to confirm C1330 and check ABS module data/commands (relay command status, pump motor status)
Swap known-good identical relay (if available) to see if code clears or behavior changes
Probe relay socket to verify presence of battery voltage on supply terminal and proper control signal from ABS module when commanded

Signal parameters

Relay supply voltage: approx. battery voltage (11.5–14.5 V) at relay power terminal with key on
Relay coil resistance (typical automotive relay): approx. 60–200 ohms (varies by relay) — check manufacturer spec if available
Control signal: relay coil is switched by ABS module (either ground-switched or +12V-switched) — expect near 0 V to ground when driven if module grounds the coil, or near battery voltage if module supplies +12V
Pump motor running voltage: ~10–14 V when commanded
Pump motor current: typical running 5–20 A; stall or fault currents can be higher (measure with proper clamp meter)
Open-circuit: infinite resistance between relay output and pump motor; short-circuit: near 0 ohms to ground or battery depending on fault

Diagnostic algorithm

Read and record freeze frame and live data with a capable scan tool; confirm C1330 and any other ABS/related codes
Perform visual inspection: check fuse, relay, pump motor connector, wiring harness for damage, corrosion, or water intrusion
Verify battery voltage at vehicle battery and at relay supply terminal (key on) — if low, charge/replace battery and retest
Inspect/replace ABS pump/relay fuse if blown; if fuse blows again, suspect short to ground or motor fault
Swap the ABS pump relay with an identical known-good relay and recheck code and pump operation
With connector(s) disconnected, measure relay coil resistance and compare to spec or similar relay; check for open coil
Backprobe relay socket while commanding ABS pump from scan tool: verify supply voltage at feed terminal and control voltage at coil terminal when commanded
Backprobe motor power connector while commanding pump: verify motor receives battery voltage and measure current draw with appropriate meter/clamp; high current suggests motor or mechanical bind, no current suggests open circuit or control fault
Check continuity and resistance of wires between relay, pump, and ABS module; repair any opens/shorts and clean/repair corroded connectors
Verify good ground at ABS module and pump motor negative connection; clean and secure grounds as needed
If wiring, relay, fuse, pump motor and grounds are good, consider ABS control module internal relay/driver failure — consult vehicle-specific procedures for module bench testing or replacement
Clear codes and road test with scan tool monitoring ABS; if code returns, proceed to replace the confirmed faulty component per vehicle procedure