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Home / DTC / B1103 — Enable the crank relay with a short ground reach (or normally open relay)

B1103 — Enable the crank relay with a short ground reach (or normally open relay)

Detailed page for trouble code B1103.

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Code

B1103

LAND ROVER B — Body

Enable the crank relay with a short ground reach (or normally open relay)

Brand: LAND ROVER
Type: B — Body
AI status
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Page language: EN

Causes

  • Short to ground on the crank-relay control circuit
  • Open or normally-open crank relay (stuck open or wrong type fitted)
  • Faulty relay socket or corroded/loose connector pins
  • Damaged wiring harness (chafing, pinched, or melted wires)
  • Blown or incorrect fuse protecting the relay circuit
  • Faulty BCM/PCM driver transistor or internal module fault

Symptoms

  • No crank or intermittent cranking condition
  • Starter does not engage when key/Start is pressed
  • Clicking sound at relay or starter when attempting to start
  • Battery drain if circuit is stuck closed
  • Malfunction Indicator Lamp (MIL) or other body DTCs present
  • Intermittent or no response from starter enable

What to check

  • Read and record all stored codes and freeze-frame data; note related codes
  • Visually inspect relay, relay socket and wiring harness for damage, corrosion or loose pins
  • Check relevant fuses and replace if blown; verify correct fuse rating
  • Swap crank relay with a known-good same-type relay (if available) and re-check
  • Back-probe relay control pin and measure voltage/continuity during crank request
  • Measure coil resistance across relay terminals with relay removed

Signal parameters

  • Control/enable line at rest (not requesting crank): open/high impedance to ground (no continuity)
  • Control/enable line when commanding crank: low, near 0 V measured to chassis ground (driver grounds the circuit)
  • Supply side to relay coil: battery voltage (approx. 12 V nominal) when relay should be energised
  • Relay coil resistance (typical): ~50–200 Ω depending on relay design (check OEM spec)
  • Expected coil current when energized: typically 50–300 mA (varies by relay)
  • If control line shows continuity to ground with ignition off — indicates unwanted short

Diagnostic algorithm

  1. Confirm B1103 and note any additional DTCs. Record conditions when code set.
  2. Visually inspect relay, socket and harness for obvious damage, corrosion or modifications.
  3. With ignition OFF, remove the crank relay. Inspect relay pins and socket for corrosion or deformation.
  4. Measure resistance between the control pin in the relay socket and chassis ground. If near 0 Ω, locate and repair short to ground in the harness.
  5. Measure relay coil resistance on the removed relay. Compare to OEM spec. Replace relay if out of spec.
  6. Reinstall a known-good relay (or swap with identical relay) and test crank request. If code clears or symptom changes, replace original relay.
  7. Back-probe the control wire at the relay socket. Command crank (use starter request via diagnostic tool or ignition) and monitor voltage. Expect near 0 V when active and open/high when inactive. If driver does not switch correctly, suspect module driver failure.
  8. If control driver appears stuck or shorted, disconnect the control connector and measure for shorts to ground from harness side. If short remains with module disconnected, repair wiring/connector. If short disappears with module disconnected, suspect module driver fault — verify with wiring diagram and further module bench tests as required.
  9. Repair or replace damaged wiring, corroded connector, or faulty relay/PCM as indicated. Use OEM replacement parts and correct relay type.
  10. Clear codes, retest multiple start cycles and perform a drive/start cycle verification to ensure code does not return.

Likely causes

  • Faulty or incorrect relay (most common)
  • Short to ground at the control wire near relay or harness
  • Corroded connector or poor pin contact at relay/power distribution
  • Defective module driver (BCM/PCM) output pin
  • Intermittent wiring break or insulation failure causing contact with chassis ground

Fault status

⚠️ Status
Crank relay enable circuit indicates a short to ground or an unexpected open-condition on the relay; module detects improper enable signal for crank relay.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-3.0 hours

Similar codes

B1100 B1101 B1102 B1104 B1110
320

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