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Home / DTC / B2456 — auxiliary heater coolant sensor - ground short circuit

B2456 — auxiliary heater coolant sensor - ground short circuit

Detailed page for trouble code B2456.

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Code

B2456

LAND ROVER B — Body

auxiliary heater coolant sensor - ground short circuit

Brand: LAND ROVER
Type: B — Body
Views: UK: 7 EN: 14 RU: 12
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Damaged or pinched wiring harness causing sensor signal shorted to ground
  • Corroded or contaminated sensor connector allowing electrical short
  • Failed auxiliary heater coolant temperature sensor (internal short)
  • Poor or missing ground at heater module or nearby grounding point
  • Faulty auxiliary heater control/module or instrument panel wiring
  • Aftermarket work or repairs that damaged wiring or connectors

Symptoms

  • Service/Warning lamp and B2456 stored in diagnostic memory
  • Auxiliary heater fails to start or operates incorrectly
  • Reduced or no cabin pre-heating from auxiliary heater
  • Intermittent operation of heater or logged intermittent DTCs
  • Possible heater fault messages displayed in vehicle info system

What to check

  • Read and record freeze frame and event data from module (confirm B2456 active/current)
  • Visually inspect sensor, connector, and wiring for damage, corrosion, or coolant contamination
  • Check related fuses and auxiliary heater relays for proper operation
  • Backprobe sensor connector and measure signal voltage with ignition on/engine as specified by manufacturer
  • Measure resistance from sensor signal pin to chassis ground to detect short
  • Inspect grounding points for corrosion and check tightness and continuity

Signal parameters

  • Sensor type: typically an NTC thermistor (resistance varies with temperature)
  • Signal voltage: reference 5 V system; expected sensor voltage varies with coolant temp (approx. 0.1–4.9 V range)
  • Ground condition for short fault: voltage near 0 V or very low resistance to chassis ground
  • Typical resistance behavior: higher resistance at low temp, lower resistance at high temp (inverse relationship) — check manufacturer spec for exact values

Diagnostic algorithm

  1. Retrieve all stored codes and freeze-frame data; confirm B2456 is present and note whether fault is current or historic.
  2. Visually inspect sensor, harness, and connector for damage, corrosion, coolant ingress, or rodent damage; repair obvious faults.
  3. With key on (engine off), backprobe sensor signal and ground pins: measure sensor signal voltage and continuity to ground. If signal is near 0 V, suspect a short to ground.
  4. Disconnect sensor connector and measure resistance from sensor harness signal wire to chassis ground. Low resistance indicates shorted wiring — trace wiring to find damage.
  5. Remove sensor and bench-test sensor resistance across terminals at ambient temperature; compare to manufacturer specification (or compare to known-good sensor) to rule out internal short.
  6. Inspect and test auxiliary heater control module ground(s) and supply circuits; repair/clean grounding points and retest.
  7. If wiring and grounds check OK, swap in a known-good sensor or install new sensor and retest for code; clear codes and perform road/operational test to confirm.
  8. If fault persists after sensor and harness replacement, test/replace auxiliary heater control module per factory procedure and recheck.
  9. After repairs, clear codes and verify no reoccurrence and correct heater operation.

Likely causes

  • Broken insulation on sensor signal wire contacting chassis ground
  • Corrosion inside sensor connector with conductive coolant/mineral deposits
  • Sensor internal failure creating low resistance to ground
  • Loose or corroded ground terminal at auxiliary heater module or chassis
  • Connector pushed in wrong orientation or bent terminal pins during service

Fault status

⚠️ Status
Auxiliary heater coolant sensor – ground short circuit (B2456)
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.0 hours

Similar codes

B2455 B2457 P0115 P0117 P0118 P0128
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

B2456

Other B — Body

Aux Heater Coolant Sensor Circuit Short to Ground

Brand: Other
Type: B — Body
Views: UK: 22 EN: 32 RU: 27
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Damaged or pinched wiring harness causing sensor signal shorted to ground
  • Corroded or contaminated sensor connector allowing electrical short
  • Failed auxiliary heater coolant temperature sensor (internal short)
  • Poor or missing ground at heater module or nearby grounding point
  • Faulty auxiliary heater control/module or instrument panel wiring
  • Aftermarket work or repairs that damaged wiring or connectors

Symptoms

  • Service/Warning lamp and B2456 stored in diagnostic memory
  • Auxiliary heater fails to start or operates incorrectly
  • Reduced or no cabin pre-heating from auxiliary heater
  • Intermittent operation of heater or logged intermittent DTCs
  • Possible heater fault messages displayed in vehicle info system

What to check

  • Read and record freeze frame and event data from module (confirm B2456 active/current)
  • Visually inspect sensor, connector, and wiring for damage, corrosion, or coolant contamination
  • Check related fuses and auxiliary heater relays for proper operation
  • Backprobe sensor connector and measure signal voltage with ignition on/engine as specified by manufacturer
  • Measure resistance from sensor signal pin to chassis ground to detect short
  • Inspect grounding points for corrosion and check tightness and continuity

Signal parameters

  • Sensor type: typically an NTC thermistor (resistance varies with temperature)
  • Signal voltage: reference 5 V system; expected sensor voltage varies with coolant temp (approx. 0.1–4.9 V range)
  • Ground condition for short fault: voltage near 0 V or very low resistance to chassis ground
  • Typical resistance behavior: higher resistance at low temp, lower resistance at high temp (inverse relationship) — check manufacturer spec for exact values

Diagnostic algorithm

  1. Retrieve all stored codes and freeze-frame data; confirm B2456 is present and note whether fault is current or historic.
  2. Visually inspect sensor, harness, and connector for damage, corrosion, coolant ingress, or rodent damage; repair obvious faults.
  3. With key on (engine off), backprobe sensor signal and ground pins: measure sensor signal voltage and continuity to ground. If signal is near 0 V, suspect a short to ground.
  4. Disconnect sensor connector and measure resistance from sensor harness signal wire to chassis ground. Low resistance indicates shorted wiring — trace wiring to find damage.
  5. Remove sensor and bench-test sensor resistance across terminals at ambient temperature; compare to manufacturer specification (or compare to known-good sensor) to rule out internal short.
  6. Inspect and test auxiliary heater control module ground(s) and supply circuits; repair/clean grounding points and retest.
  7. If wiring and grounds check OK, swap in a known-good sensor or install new sensor and retest for code; clear codes and perform road/operational test to confirm.
  8. If fault persists after sensor and harness replacement, test/replace auxiliary heater control module per factory procedure and recheck.
  9. After repairs, clear codes and verify no reoccurrence and correct heater operation.

Likely causes

  • Broken insulation on sensor signal wire contacting chassis ground
  • Corrosion inside sensor connector with conductive coolant/mineral deposits
  • Sensor internal failure creating low resistance to ground
  • Loose or corroded ground terminal at auxiliary heater module or chassis
  • Connector pushed in wrong orientation or bent terminal pins during service

Fault status

⚠️ Status
Auxiliary heater coolant sensor – ground short circuit (B2456)
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.0 hours

Similar codes

B2455 B2457 P0115 P0117 P0118 P0128
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