Toggle Side Panel

Shopping Cart

No products in the basket.

Shopping Cart

No products in the basket.

Close search
Home / DTC / B1017 — Heater water TEMP. sensor high

B1017 — Heater water TEMP. sensor high

Detailed page for trouble code B1017.

34,336codes
59brands
11,845generic
22,491specific
All codes P-codes (Powertrain) B-codes (Body) C-codes (Chassis) U-codes (Network/User) Tesla Alerts
Reset
Code

B1017

MITSUBISHI B — Body

Heater water TEMP. sensor high

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

Causes

  • Open or shorted wiring between heater water temperature sensor and control module
  • Corroded, loose, or damaged sensor connector
  • Faulty heater water temperature sensor (thermistor)
  • Faulty HVAC/heater control module or incorrect reference voltage
  • Water intrusion or corrosion at sensor/harness
  • Incorrect installation or mechanical damage to sensor or harness

Symptoms

  • Heater temperature incorrect or not controllable
  • HVAC shows erroneous temperature readout or fault indicator
  • Reduced or no heat from vents despite warm engine coolant
  • Duct blend doors not responding properly (if controlled by temp feedback)
  • Possible stored HVAC-related fault codes

What to check

  • Retrieve freeze frame and related HVAC/engine codes before clearing
  • Visually inspect sensor connector and wiring for corrosion, damage, or disconnection
  • Check for water intrusion in heater box or sensor area
  • Measure sensor harness voltage with key ON (reference voltage) and check for proper ground
  • Measure sensor resistance at known coolant temperatures and compare to specification
  • Backprobe sensor signal at HVAC control module to confirm wiring integrity

Signal parameters

  • Sensor type: typically NTC thermistor (resistance decreases as temperature rises)
  • Typical resistance — room temp (≈20°C): usually in kilohm range (manufacturer-specific)
  • Typical resistance — operating temp (≈80–100°C): usually several hundred ohms (manufacturer-specific)
  • Expected signal voltage to control module: variable with temp; commonly between ~0.2–4.8 V depending on circuit
  • B1017 indicates a higher-than-expected signal (open circuit, short to battery, or extreme high-temperature reading)

Diagnostic algorithm

  1. Verify: Record vehicle details, read and record all HVAC and engine codes and freeze frame data.
  2. Visual: Inspect the heater water temp sensor, connector, and wiring for damage, corrosion, or coolant contamination. Repair visible issues.
  3. Power/Ground: With ignition ON (engine OFF), backprobe the sensor connector. Verify reference voltage (usually 5V or a sensor supply) and ground presence at the harness side.
  4. Signal check: Measure the sensor signal voltage at the connector; compare with expected live values (should change with coolant temp).
  5. Resistance check: Remove sensor and measure its resistance at ambient and warmed coolant temperatures. Compare to manufacturer spec; an open or out-of-spec reading indicates a bad sensor.
  6. Wiring continuity: If voltages are not as expected, check continuity from the sensor connector to the HVAC control module and check for short to battery or short to ground.
  7. Module test: If wiring and sensor are good, verify the HVAC/heater control module output and reference voltages. Replace module only after eliminating wiring and sensor faults.
  8. Repair and verify: Replace faulty sensor or repair wiring as required. Clear codes, run the vehicle to operating temperature, and confirm the code does not return and heater function is normal.

Likely causes

  • Disconnected or corroded harness connector at the sensor
  • Broken wiring or chafed insulation causing open circuit
  • Sensor internal failure (open circuit or out-of-spec resistance)
  • Short to battery/ignition voltage in sensor circuit
  • Poor ground or intermittent connection at HVAC module

Fault status

⚠️ Status
Heater water temperature sensor circuit indicates high signal — possible open circuit, short to voltage, or sensor/module fault affecting heater temperature control.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours
406

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

MITSUBISHI

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

Report

Harassment or bullying behavior
Contains mature or sensitive content
Contains misleading or false information
Contains abusive or derogatory content
Contains spam, fake content or potential malware

Block Member?

Please confirm you want to block this member.

You will no longer be able to:

  • See blocked member's posts
  • Mention this member in posts
  • Invite this member to groups
  • Message this member
  • Add this member as a connection

Please note: This action will also remove this member from your connections and send a report to the site admin. Please allow a few minutes for this process to complete.

Report

You have already reported this .