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Home / DTC / B2451 — Fuel pump of the auxiliary heater - short circuit to ground

B2451 — Fuel pump of the auxiliary heater - short circuit to ground

Detailed page for trouble code B2451.

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Code

B2451

LAND ROVER B — Body

Fuel pump of the auxiliary heater - short circuit to ground

Brand: LAND ROVER
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Damaged/chafed wiring harness with insulation worn through to chassis ground
  • Corroded or bridged connector pins at the auxiliary heater pump or junctions
  • Internal short inside the auxiliary heater fuel pump motor
  • Faulty relay or control module output transistor (shorted to ground)
  • Water or debris ingress in pump or connector causing conductive path to ground
  • Incorrect aftermarket wiring or accessories tied into the pump circuit

Symptoms

  • Auxiliary heater fails to run or shuts down immediately when commanded
  • Blown fuse(s) related to the auxiliary heater/pump circuit
  • Set fault lamp or stored B2451 code in vehicle fault memory
  • Battery or wiring smells or signs of overheating in extreme short cases
  • Possible parasitic drain or inability to operate auxiliary heater remotely

What to check

  • Retrieve freeze‑frame and related codes; check operation history of auxiliary heater
  • Visually inspect pump connector, wiring harness, and routing for abrasion, burns, or corrosion
  • Check relevant fuses and relays for blown/faulty condition (replace with correct rating before testing)
  • Disconnect the auxiliary heater pump connector and measure resistance between the pump supply pin and chassis ground
  • Measure resistance between the supply feed (with connector disconnected) and ground — look for low (
  • Backprobe/monitor control output from heater control module or relay with a DVOM/oscilloscope while commanding pump

Signal parameters

  • Battery supply to pump (with ignition/on or heater commanded): ~12 V (vehicle battery voltage). Consult manual for exact test conditions.
  • Expected pump motor resistance (typical): roughly 1–20 Ω depending on design — consult vehicle workshop spec. Very low (
  • Expected pump current when running: typically in the ampere range (commonly 1–10 A). A much higher current indicates internal short or stalled motor.
  • Control output behavior: relay or ECU driver should switch supply/ground only when heater is commanded. With pump disconnected the control line should not show a direct short to chassis ground.
  • Short condition: continuity from pump feed to ground with connector disconnected indicates wiring short; near 0 Ω is a hard short.

Diagnostic algorithm

  1. Read and record all stored codes and freeze frame data. Do not clear codes before diagnosis.
  2. Visually inspect pump, connector, and wiring harness for damage, corrosion, melted insulation, or signs of heat. Pay attention to common chafe points and routing near moving parts.
  3. Check fuses/relays for the auxiliary heater/pump circuit and replace if blown. If a new fuse blows immediately when attempting to operate, proceed carefully to locate the short.
  4. With ignition off, disconnect the auxiliary heater pump connector. Using a multimeter set to resistance/continuity, measure between the pump supply pin and chassis ground. If low resistance/continuity exists with the connector disconnected, the short is in the vehicle wiring or a downstream module.
  5. If no short is present with connector disconnected, bench‑test the pump: apply a fused 12 V supply directly to the pump terminals and measure current draw. Excessive current or no rotation indicates a faulty pump — replace pump assembly.
  6. If the short is in the wiring: isolate sections of the harness by disconnecting intermediate connectors and repeat continuity checks until the shorted segment is found. Inspect and repair the damaged wiring (splice with correct gauge, heat‑shrink, and protect routing).
  7. If wiring and pump check good, backprobe the control relay or heater control module output while commanding the heater. If the module driver is shorted to ground, verify wiring disconnected from module to confirm, then consider module replacement per manufacturer guidance.
  8. After repair, reconnect everything, clear DTCs, and perform a full functional test of the auxiliary heater through several cycles. Monitor for recurrence and re‑scan for related codes.
  9. If diagnostics are beyond available tools or the short is internal to a control module, consult dealer or specialist with appropriate OEM tooling.

Likely causes

  • Chafed wiring near the auxiliary heater or along the harness (most common)
  • Corroded/contaminated connector at the pump or inline connector
  • Failed fuel pump motor with internal short
  • Failed heater control relay or driver in control module

Fault status

⚠️ Status
Auxiliary heater fuel pump circuit — short to ground detected. Overcurrent/low resistance condition observed when pump commanded.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-3 hours

Similar codes

B2450 B2452 B2453 P0230 B1228
320

Browse 320 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

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Code

B2451

MITSUBISHI B — Body

Audio panel type error

Brand: MITSUBISHI
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Damaged/chafed wiring harness with insulation worn through to chassis ground
  • Corroded or bridged connector pins at the auxiliary heater pump or junctions
  • Internal short inside the auxiliary heater fuel pump motor
  • Faulty relay or control module output transistor (shorted to ground)
  • Water or debris ingress in pump or connector causing conductive path to ground
  • Incorrect aftermarket wiring or accessories tied into the pump circuit

Symptoms

  • Auxiliary heater fails to run or shuts down immediately when commanded
  • Blown fuse(s) related to the auxiliary heater/pump circuit
  • Set fault lamp or stored B2451 code in vehicle fault memory
  • Battery or wiring smells or signs of overheating in extreme short cases
  • Possible parasitic drain or inability to operate auxiliary heater remotely

What to check

  • Retrieve freeze‑frame and related codes; check operation history of auxiliary heater
  • Visually inspect pump connector, wiring harness, and routing for abrasion, burns, or corrosion
  • Check relevant fuses and relays for blown/faulty condition (replace with correct rating before testing)
  • Disconnect the auxiliary heater pump connector and measure resistance between the pump supply pin and chassis ground
  • Measure resistance between the supply feed (with connector disconnected) and ground — look for low (
  • Backprobe/monitor control output from heater control module or relay with a DVOM/oscilloscope while commanding pump

Signal parameters

  • Battery supply to pump (with ignition/on or heater commanded): ~12 V (vehicle battery voltage). Consult manual for exact test conditions.
  • Expected pump motor resistance (typical): roughly 1–20 Ω depending on design — consult vehicle workshop spec. Very low (
  • Expected pump current when running: typically in the ampere range (commonly 1–10 A). A much higher current indicates internal short or stalled motor.
  • Control output behavior: relay or ECU driver should switch supply/ground only when heater is commanded. With pump disconnected the control line should not show a direct short to chassis ground.
  • Short condition: continuity from pump feed to ground with connector disconnected indicates wiring short; near 0 Ω is a hard short.

Diagnostic algorithm

  1. Read and record all stored codes and freeze frame data. Do not clear codes before diagnosis.
  2. Visually inspect pump, connector, and wiring harness for damage, corrosion, melted insulation, or signs of heat. Pay attention to common chafe points and routing near moving parts.
  3. Check fuses/relays for the auxiliary heater/pump circuit and replace if blown. If a new fuse blows immediately when attempting to operate, proceed carefully to locate the short.
  4. With ignition off, disconnect the auxiliary heater pump connector. Using a multimeter set to resistance/continuity, measure between the pump supply pin and chassis ground. If low resistance/continuity exists with the connector disconnected, the short is in the vehicle wiring or a downstream module.
  5. If no short is present with connector disconnected, bench‑test the pump: apply a fused 12 V supply directly to the pump terminals and measure current draw. Excessive current or no rotation indicates a faulty pump — replace pump assembly.
  6. If the short is in the wiring: isolate sections of the harness by disconnecting intermediate connectors and repeat continuity checks until the shorted segment is found. Inspect and repair the damaged wiring (splice with correct gauge, heat‑shrink, and protect routing).
  7. If wiring and pump check good, backprobe the control relay or heater control module output while commanding the heater. If the module driver is shorted to ground, verify wiring disconnected from module to confirm, then consider module replacement per manufacturer guidance.
  8. After repair, reconnect everything, clear DTCs, and perform a full functional test of the auxiliary heater through several cycles. Monitor for recurrence and re‑scan for related codes.
  9. If diagnostics are beyond available tools or the short is internal to a control module, consult dealer or specialist with appropriate OEM tooling.

Likely causes

  • Chafed wiring near the auxiliary heater or along the harness (most common)
  • Corroded/contaminated connector at the pump or inline connector
  • Failed fuel pump motor with internal short
  • Failed heater control relay or driver in control module

Fault status

⚠️ Status
Auxiliary heater fuel pump circuit — short to ground detected. Overcurrent/low resistance condition observed when pump commanded.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-3 hours

Similar codes

B2450 B2452 B2453 P0230 B1228
406

Browse 406 MITSUBISHI manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

MITSUBISHI

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+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

B2451

Other B — Body

Aux Heater Fuel Pump Circuit Short to Ground

Brand: Other
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Damaged/chafed wiring harness with insulation worn through to chassis ground
  • Corroded or bridged connector pins at the auxiliary heater pump or junctions
  • Internal short inside the auxiliary heater fuel pump motor
  • Faulty relay or control module output transistor (shorted to ground)
  • Water or debris ingress in pump or connector causing conductive path to ground
  • Incorrect aftermarket wiring or accessories tied into the pump circuit

Symptoms

  • Auxiliary heater fails to run or shuts down immediately when commanded
  • Blown fuse(s) related to the auxiliary heater/pump circuit
  • Set fault lamp or stored B2451 code in vehicle fault memory
  • Battery or wiring smells or signs of overheating in extreme short cases
  • Possible parasitic drain or inability to operate auxiliary heater remotely

What to check

  • Retrieve freeze‑frame and related codes; check operation history of auxiliary heater
  • Visually inspect pump connector, wiring harness, and routing for abrasion, burns, or corrosion
  • Check relevant fuses and relays for blown/faulty condition (replace with correct rating before testing)
  • Disconnect the auxiliary heater pump connector and measure resistance between the pump supply pin and chassis ground
  • Measure resistance between the supply feed (with connector disconnected) and ground — look for low (
  • Backprobe/monitor control output from heater control module or relay with a DVOM/oscilloscope while commanding pump

Signal parameters

  • Battery supply to pump (with ignition/on or heater commanded): ~12 V (vehicle battery voltage). Consult manual for exact test conditions.
  • Expected pump motor resistance (typical): roughly 1–20 Ω depending on design — consult vehicle workshop spec. Very low (
  • Expected pump current when running: typically in the ampere range (commonly 1–10 A). A much higher current indicates internal short or stalled motor.
  • Control output behavior: relay or ECU driver should switch supply/ground only when heater is commanded. With pump disconnected the control line should not show a direct short to chassis ground.
  • Short condition: continuity from pump feed to ground with connector disconnected indicates wiring short; near 0 Ω is a hard short.

Diagnostic algorithm

  1. Read and record all stored codes and freeze frame data. Do not clear codes before diagnosis.
  2. Visually inspect pump, connector, and wiring harness for damage, corrosion, melted insulation, or signs of heat. Pay attention to common chafe points and routing near moving parts.
  3. Check fuses/relays for the auxiliary heater/pump circuit and replace if blown. If a new fuse blows immediately when attempting to operate, proceed carefully to locate the short.
  4. With ignition off, disconnect the auxiliary heater pump connector. Using a multimeter set to resistance/continuity, measure between the pump supply pin and chassis ground. If low resistance/continuity exists with the connector disconnected, the short is in the vehicle wiring or a downstream module.
  5. If no short is present with connector disconnected, bench‑test the pump: apply a fused 12 V supply directly to the pump terminals and measure current draw. Excessive current or no rotation indicates a faulty pump — replace pump assembly.
  6. If the short is in the wiring: isolate sections of the harness by disconnecting intermediate connectors and repeat continuity checks until the shorted segment is found. Inspect and repair the damaged wiring (splice with correct gauge, heat‑shrink, and protect routing).
  7. If wiring and pump check good, backprobe the control relay or heater control module output while commanding the heater. If the module driver is shorted to ground, verify wiring disconnected from module to confirm, then consider module replacement per manufacturer guidance.
  8. After repair, reconnect everything, clear DTCs, and perform a full functional test of the auxiliary heater through several cycles. Monitor for recurrence and re‑scan for related codes.
  9. If diagnostics are beyond available tools or the short is internal to a control module, consult dealer or specialist with appropriate OEM tooling.

Likely causes

  • Chafed wiring near the auxiliary heater or along the harness (most common)
  • Corroded/contaminated connector at the pump or inline connector
  • Failed fuel pump motor with internal short
  • Failed heater control relay or driver in control module

Fault status

⚠️ Status
Auxiliary heater fuel pump circuit — short to ground detected. Overcurrent/low resistance condition observed when pump commanded.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1-3 hours

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B2450 B2452 B2453 P0230 B1228
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