Toggle Side Panel

Shopping Cart

No products in the basket.

Shopping Cart

No products in the basket.

Close search
Home / DTC / B1023 — Air thermo sensor open

B1023 — Air thermo sensor open

Detailed page for trouble code B1023.

34,405codes
59brands
11,914generic
22,491specific
All codes P-codes (Powertrain) B-codes (Body) C-codes (Chassis) U-codes (Network/User) Tesla Alerts
Reset
Code

B1023

MITSUBISHI B — Body

Air thermo sensor open

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

Causes

  • Broken or disconnected sensor wiring or connector
  • Corroded or bent terminals at the sensor or ECU/BCM connector
  • Failed air thermo sensor (open internal thermistor)
  • Poor or missing ground/return
  • Water ingress or contamination at connector
  • Faulty HVAC control module / BCM (less common)

Symptoms

  • HVAC displays incorrect or no outside/air temperature reading
  • Automatic climate control may not regulate correctly (runs incorrectly, constant blower or compressor behaviour)
  • DTC stored and possibly illuminated HVAC or body warning
  • Intermittent operation if wiring is damaged

What to check

  • Use a scan tool to confirm B1023 is current and check freeze-frame data
  • Visual inspection of sensor location, wiring harness and connectors for damage or corrosion
  • Wiggle test harness while monitoring live data or DTC status
  • Measure connector pins for corrosion, pin fit, and secure mating
  • Check for water or debris in the sensor area (evaporator / cowl / bumper area depending on sensor)

Signal parameters

  • Sensor type: typically an NTC thermistor (resistance decreases as temperature rises)
  • Expected behavior: high resistance at low temp, lower resistance at high temp (check OEM spec curve)
  • Common voltage interface: signal typically between ~0.5 V and ~4.5 V (depends on vehicle) with a pull-up or pull-down in the module
  • Open-circuit indication: very high or infinite resistance; signal voltage may read near reference rail (0V or supply voltage)
  • Short indication: near 0 Ω or near a rail voltage depending on wiring

Diagnostic algorithm

  1. Verify the code with an OBD/scan tool and record freeze-frame/live data for the air temperature sensor.
  2. Visually inspect the sensor, connector and wiring harness for damage, corrosion, water or loose pins. Repair any obvious issues.
  3. Backprobe the sensor connector and measure the sensor circuit voltage with ignition ON. Compare to expected voltage (refer to service manual).
  4. With the sensor disconnected, measure resistance across the sensor terminals. Compare resistance to OEM specification at ambient temperature (if no spec, confirm non-infinite resistance for a thermistor).
  5. Check continuity between the sensor connector and the HVAC/BCM connector; check for short to ground or to battery via insulation/continuity tester.
  6. If wiring and connectors check good, replace the air thermo sensor and re-test resistance/voltage and live-data response (observe resistance change when warming/cooling sensor).
  7. If a new sensor does not restore function, suspect HVAC control module/BCM input fault; verify module grounds, power supplies and consult wiring diagram before replacing module.
  8. Clear codes, perform functional test and re-check for reappearance of B1023 after road or operational test.

Likely causes

  • Open or damaged wiring between sensor and HVAC/BCM
  • Failed sensor (open thermistor element)
  • Connector corrosion or loose terminal
  • Ground/return fault
  • Control module input fault

Fault status

⚠️ Status
Open circuit detected in air temperature sensor circuit — sensor not providing valid temperature signal to control module.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 0.5-2.0 hours

Similar codes

B1021 B1024 P0112 P0113 B1020
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 .