01 How Self-Driving Cars See and Detect Objects • 02 The Mitsubishi Outlander PHEV: A Plug-in Hybrid SUV That Ch… • 03 Streamlining Fluid Maintenance with RPM Oil Evacuation Syst… • 04 Unleashing the Power of Variable Geometry Turbochargers: A … • 05 This Is Why It’s Almost Impossible To Sink A Modern Cruise … • 06 Oil filter vs. oil: Which is more important to change? • 07 Troubleshooting Black Smoke: Diagnosing Fuel-to-Air Issues … • 08 This Is Why Your Car’s EGR Valve Is Stuck • 09 The Wankel Rotary Engine: Compact, Smooth, and Powerful • 10 Why Dirty Grounds Cause More Car Problems Than People Reali… •

DTC codes / Mitsubishi codes / P1492

P1492 · MitsubishiBattery Temperature Sensor High Voltage

P1492 on Mitsubishi vehicles means the battery temperature sensor circuit is reporting a voltage higher than the powertrain control module expects, which the computer interprets as an open circuit or excessive resistance in the sensor or its wiring. The sensor itself is a thermistor that changes resistance with temperature, and a high signal voltage tells the PCM the battery is colder than it actually is or that the circuit has lost its ground reference.

SystemPowertrain
Code typeMitsubishi specific
SeverityLow
Fix difficultyIntermediate
AreaAuxiliary emission controls

Symptoms you may notice

  • Illumination of the check engine light or service engine soon light, often with no other noticeable symptoms.
  • Slightly reduced fuel economy or altered charging strategy if the PCM substitutes a default battery temperature value.
  • In cold climates, the charging system may overcharge or undercharge because the PCM misjudges battery temperature.
  • Intermittent warning light that comes and goes with vibration or temperature changes if the fault is a loose connection.
  • No drivability complaints in most cases because the battery temperature signal is used mainly for charging and emissions strategy.

Common causes, most likely first

  1. Failed battery temperature sensor, typically an open thermistor element inside the sensor housing.
  2. Corroded, broken, or disconnected signal wire between the sensor and the PCM, causing an open circuit.
  3. Poor ground connection at the sensor or at the PCM ground point, raising the return voltage.
  4. Damaged sensor connector pins or terminals that have backed out of the housing.
  5. Faulty PCM driver or internal pull-up resistor, though this is the least common cause.
  6. Aftermarket battery or tray installation that pinched or routed the sensor harness incorrectly.

How to diagnose and fix it

  1. Clear the code and road-test the vehicle to confirm whether P1492 returns as a hard or intermittent fault.
  2. Inspect the battery temperature sensor connector and harness for corrosion, chafing, or a loose fit, and repair terminals as needed.
  3. Measure sensor resistance with a multimeter and compare it to the expected value for the ambient temperature; an open or out-of-range reading condemns the sensor.
  4. Back-probe the signal wire at the PCM and check for a high voltage that does not change when the sensor is unplugged, which points to a wiring open circuit.
  5. Check the sensor ground circuit for excessive resistance using a voltage drop test rather than a simple continuity check.
  6. Replace the battery temperature sensor if resistance testing confirms it is open or out of specification, then clear codes and verify the signal voltage returns to normal.
  7. If wiring and sensor test good, perform a wiggle test on the harness while watching live data to catch an intermittent open before condemning the PCM.

Battery temperature sensor circuit traps

  • A high-voltage code for this sensor almost always means an open circuit rather than a genuinely hot battery, so technicians who replace the battery first are usually chasing the wrong part.
  • The sensor is often integrated into the battery tray or negative cable assembly on Mitsubishi models, so a corroded tray or a cable replacement can leave the connector unplugged and set P1492.
  • Because the PCM uses battery temperature to adjust charging voltage, a faulty sensor can mask itself as a charging system complaint with no drivability symptom at all.
  • A poor chassis ground near the battery can raise the sensor return voltage and set this code even when the sensor and signal wire test perfectly good.
  • Clearing the code without checking freeze-frame data can hide an intermittent fault that only appears during cold starts or after a long soak.

Can I keep driving with P1492?

It is safe to continue driving with P1492 because the fault affects charging strategy rather than engine operation, but avoid long trips in extreme cold or heat until the circuit is repaired. Have the charging system checked if the battery warning light also appears.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Mitsubishi vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage