Open circuit or high resistance in the battery temperature sensor signal or ground wire; Corroded, loose or damaged sensor connector or harness plug; Failed battery temperature sensor (internal open circuit); Signal wire shorted to a voltage supply elsewhere in the harness; Corroded battery terminals or poor earth connections affecting sensor reference; Fault inside the powertrain control module.

P1492

Battery Temperature Sensor Voltage Too High.

Jeep
Powertrain
Manufacturer code
Medium severity

How this code is built

P: SystemPowertrain
1: Defined byThe manufacturer
4: AreaAuxiliary emission controls
92: FaultThe specific fault in that area

What it means

P1492 on a Jeep means the powertrain control module has seen the battery temperature sensor signal voltage sit higher than expected, which usually points to an open circuit, a poor connection or a failed sensor. The module uses this reading to adjust charging voltage to suit battery temperature, so a faulty signal can make it fall back on a default value. The exact sensor location and wiring layout depend on the model and engine.

Symptoms

Battery or charging system warning light on, or the engine management light illuminated
Battery undercharged or repeatedly flat in cold weather
Battery overcharged, with signs such as swollen case or boiling electrolyte, in severe or prolonged cases
Dim headlights or fluctuating electrical system voltage
No noticeable symptoms other than the stored fault code

Possible causes

Open circuit or high resistance in the battery temperature sensor signal or ground wirelikely
Corroded, loose or damaged sensor connector or harness pluglikely
Failed battery temperature sensor (internal open circuit)likely
Signal wire shorted to a voltage supply elsewhere in the harnesspossible
Corroded battery terminals or poor earth connections affecting sensor referencepossible
Fault inside the powertrain control modulerare

How to diagnose

Read the stored and pending codes and freeze frame data, noting whether the fault is current or intermittent, and check for any charging system codes
Visually inspect the battery temperature sensor, its harness and connector for damage, corrosion, chafing or heat damage, referring to the model-specific location
Inspect the battery terminals, cables and earth points for corrosion or looseness, and clean or tighten as needed
Check the live battery temperature sensor reading against actual ambient or battery temperature when the car has been standing; an implausibly low temperature reading suggests an open circuit
Disconnect the sensor and measure its resistance, comparing it with the manufacturer specification for the temperature at the time
With the sensor unplugged, check the reference voltage, signal wire and ground for continuity, and for shorts to voltage or ground using the wiring diagram
Test the battery state of health and the charging system output to confirm the battery and alternator are working properly
Only if wiring and sensor test correctly, check the control module's power and earth supplies before suspecting the module

How to fix

Repair or replace damaged wiring in the signal or ground circuit, making sure the repair is properly sealed
Clean, refit or replace a corroded or damaged connector
Replace the battery temperature sensor if its resistance is out of specification
Repair any short to voltage in the harness
Clean and tighten battery terminals and earth connections, replacing damaged cables
Replace or reprogram the powertrain control module only after all other causes are ruled out and the manufacturer procedure confirms it

Can I keep driving?

Medium severity

The car can usually be driven short term, but the charging strategy may be inaccurate, which can leave the battery undercharged or overcharged. Have it checked soon, and avoid long journeys if the battery or charging warning lights are on.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.