P0298 on 2012-2013 Fiat 500: Engine Oil Temperature Too High Causes & Fixes

What's Unique About the 2012-2013 Fiat 500

For the 2012-2013 Fiat 500, this code has a very specific and well-documented history. A large number of cases are not caused by a mechanical failure but by a software sensitivity issue within the Powertrain Control Module (PCM). Fiat Chrysler Automobiles (FCA) issued multiple TSBs acknowledging that this code, along with others like P1239 (Oil Temp Too Low) and P2610 (PCM Timer Performance), could be set erroneously. The official fix in these non-mechanical situations is a simple software reflash performed by a dealer, which recalibrates the system's logic. This is so common that it should be the first diagnostic check if no physical overheating symptoms are present.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Check Engine Light (Malfunction Indicator Lamp) is on
• Engine temperature gauge reading higher than normal
• Reduced engine power or the vehicle enters "limp mode"
• Warning message on the instrument cluster (e.g., "Oil Temp High")
• Smell of burning oil
• Engine knocking or ticking noises in severe cases
• Cooling fan running constantly or more than usual

Most Likely Causes

1. PCM Software Glitch 🔴 High Probability Multiple TSBs (#18-053-16, #18-027-15, #18-007-14) were issued by the manufacturer to address this specific code being triggered erroneously. This is the most unique and platform-specific cause, often occurring without any actual overheating.
   How to confirm: A Fiat dealer or a qualified shop with a wiTECH scan tool can check the current software version of the PCM and determine if the update specified in the TSBs has been applied. If the update is available and no other symptoms are present, this is the likely cause.
   Typical fix: Reprogramming (flashing) the Powertrain Control Module (PCM) with the updated software. This is a service, not a part replacement.
   Est. part cost: $0
2. Faulty Engine Oil Temperature (EOT) Sensor 🟡 Medium Probability Sensors can fail over time, sending incorrect high-temperature readings to the PCM even when the oil temperature is normal. Forum users have reported successfully fixing the P0298 code by replacing this sensor after a PCM flash did not work.
   How to confirm: Use an OBD-II scanner to monitor the EOT sensor's live data. If it reads an extremely high temperature on a cold engine, the sensor or its circuit is faulty. Compare the reading to the coolant temperature on a cold engine; they should be similar. The sensor is part of the MultiAir actuator assembly.
   Typical fix: Replace the engine oil temperature sensor. This may require a special tool like a 13mm injector fuel line socket for access.
   Est. part cost: $40-$80
3. Low Engine Oil Level 🟡 Medium Probability The 1.4L engine can consume oil, and leaks can develop. Insufficient oil cannot dissipate heat effectively, causing the remaining oil to overheat.
   How to confirm: Check the engine oil dipstick when the engine is cool and on a level surface. The oil level should be between the 'MIN' and 'MAX' marks.
   Typical fix: Top up the engine oil to the correct level using the manufacturer-specified grade (e.g., SAE 5W-40 synthetic). If the level is low due to a leak, the leak must be identified and repaired.
   Est. part cost: $10-$50
4. General Cooling System Malfunction ⚪ Low Probability Like any vehicle, issues like a stuck thermostat, failing water pump, low coolant, or a malfunctioning cooling fan will cause the entire engine to overheat, which in turn overheats the oil. Some owners report thermostat issues on the Fiat 500 platform.
   How to confirm: Check the coolant level. Observe the engine temperature gauge for overheating. Check if the cooling fan turns on when the engine gets hot. A mechanic can perform a cooling system pressure test to find leaks.
   Typical fix: Repair depends on the specific fault: replace thermostat, water pump, radiator, or fix leaks and refill with coolant.
   Est. part cost: $50-$500

Rare But Worth Checking

• Clogged or Failing Engine Oil Cooler: → Shop Engine Oil Cooler On turbocharged models (Abarth, 500T), the oil cooler plays a vital role. A blockage or internal failure can directly lead to high oil temperatures. In some cases, a failed oil cooler can cause oil and coolant to mix. This is a more severe and costly repair.

Diagnosis Steps

1. Check for other symptoms: Is the engine actually overheating (high temp gauge, steam, smell of burning oil)? If not, a sensor or software issue is more likely.
2. Verify Engine Oil Level & Condition: Turn off the engine, wait 5-10 minutes, and check the dipstick on level ground. Ensure oil is at the correct level and not milky (which would indicate coolant contamination). Top up if low.
3. Verify Coolant Level: Check the coolant reservoir. If low, top up and inspect for leaks. A sloshing sound from the dashboard can indicate air in the system from a low coolant level.
4. Scan for Codes: Use an OBD-II scanner to confirm P0298 and check for any other related codes, especially P2610, P1239, or P2299, which point towards the TSB software fix.
5. Analyze Live Data: Use the scanner to monitor Engine Oil Temperature (EOT) and Engine Coolant Temperature (ECT). On a cold start, they should be close to ambient temperature. If the EOT is immediately high (e.g., >250°F), the sensor or wiring is likely faulty. While driving, watch for abnormal spikes that don't correlate with engine load.
6. Check for TSBs: This is a critical step. Ask a dealer or use a professional database to see if TSB #18-053-16 has been performed. If the vehicle's software has not been updated, this is the most probable and manufacturer-recommended fix.
7. Inspect EOT Sensor and Wiring: Locate the sensor, which is integrated into the MultiAir actuator. Inspect its connector and wiring for damage, corrosion, or oil contamination.
🎬 See this walkthrough for locating and replacing the oil sensor.
8. Test Cooling System: If actual overheating is suspected, verify the cooling fan operation, check for a stuck thermostat, and perform a cooling system pressure test to rule out leaks.
🎬 Watch: How to diagnose the P0298 code and cooling system issues.

Parts You'll Likely Need

• PCM Reflash Service — This is not a physical part, but a service. It is the most common, documented fix for this specific code on this vehicle when no mechanical fault is present, per multiple manufacturer TSBs.
  Trusted brands: Fiat/Mopar Dealer Service
  OEM price range: $100-$250
• Engine Oil Temperature Sensor (OEM #68088241AA (replaces 68119586AA)) — If the PCM update does not resolve the issue or if live data shows erratic readings, the sensor itself is the next most likely culprit. This sensor is described as being for 'Air Temperature in the Multiair Actuator' and 'Oil Temperature'.
  Trusted brands: Mopar
  OEM price range: $210-$325
  Aftermarket price range: $40-$80

Related Codes That Often Appear With This One

• P2610 — PCM Internal Engine Off Timer Performance. This code is listed alongside P0298 in the same TSBs, indicating they are often resolved together by a PCM software update.
• P1239 — Engine Oil Temperature Too Low. It may seem contradictory, but this code is also listed in the same TSBs as P0298, pointing to a general issue with the PCM's ability to interpret oil temperature data correctly.
• P2299 — Brake Pedal Position / Accelerator Pedal Position Incompatible. This is another code frequently cited in the same Fiat TSBs, suggesting a broad software update addresses multiple unrelated-seeming electronic issues.

Technical Service Bulletins (TSBs) & Recalls

• 18-053-16: Flash: 1.4L Diagnostic And System Improvements. Addresses P0298 among other codes fixed by a PCM reflash.
• 18-027-15 REV C: Predecessor to TSB 18-053-16, also addressing P0298 with a software update.
• 18-027-15 REV-B: An earlier revision of the same software update TSB.
• 18-007-14 REV. B: An even earlier TSB that also lists P0298 as being resolved by a PCM flash.

Platform-Specific Known Issues

• The primary vehicle-specific issue is the high likelihood that code P0298 is caused by a software error in the Powertrain Control Module (PCM). This was acknowledged by Fiat in TSBs #18-053-16, #18-027-15 REV C, #18-027-15 REV-B, and #18-007-14 REV. B. The TSBs apply to vehicles with the 1.4L MultiAir (Sales Code EAB) and 1.4L MultiAir Turbo (Sales Code EAF) engines.

Mechanic-Grade Diagnostic Values

• Engine Oil Temperature (EOT) Sensor Resistance — expected: Approximately 2080-2500 Ohms at 25°C (77°F) and 294-320 Ohms at 80°C (176°F). Resistance should decrease smoothly as temperature increases.. Failure: An open circuit (infinite resistance) or short circuit (near-zero resistance) at any temperature. Readings that do not change with temperature or are drastically outside the expected range.
• Engine Oil Temperature (EOT) Sensor Signal Voltage (Key On, Engine Off) — expected: Approximately 2.0V to 3.0V on a cold engine. The voltage will decrease as the engine warms up.. Failure: Voltage near 5.0V may indicate an open circuit or bad ground. Voltage near 0V indicates a short to ground.

Scan Tool Commands That Help

• wiTECH / wiTECH 2.0: Reprogram the PCM / Flash Control Module — This is the primary repair step specified by multiple Fiat TSBs for erroneously set P0298 codes when no actual overheating condition exists. It should be performed by a dealer or qualified shop if the vehicle's software is outdated.
• wiTECH / wiTECH 2.0: View Live Data — To monitor the EOT and ECT sensor readings in real-time to check for erratic behavior or values that are out of specification, which helps differentiate a sensor failure from a software issue.

Wiring & Ground Locations

• Engine Oil Temperature Sensor — Located on the variable valve actuation (MultiAir) assembly at the rear of the engine.. This is the primary sensor providing the data that triggers the P0298 code. Its location is necessary for inspection of the sensor and its connector for damage or corrosion.
• Main Engine/Chassis Ground Strap — Runs from the negative battery terminal, connects to the chassis/body just below the battery tray, and then continues down to a bolt on the gearbox.. Corrosion or failure of this main ground is a known issue on Fiat 500s and can cause a wide range of difficult-to-diagnose electrical faults, including erroneous sensor readings and fault codes that refuse to clear. Checking this ground is a critical step if electrical issues are suspected.

Real Owner Repair Stories

• Reddit user u/uac2113 (Fiat 500 (year not specified, but in a thread about P0298)) — P0298 code present.
  ❌ Tried (didn't work) The original poster tried multiple oil and filter changes with different brands.
  ✅ What actually fixed it Replacing the engine oil temperature sensor was the final solution. A special '13mm injector fuel line socket' was required for the job.
• Reddit user u/DixonUrjas (Fiat 500 (year not specified)) — P0298 code appeared after an oil change.
  ✅ What actually fixed it The electrical plug under the oil filter was found to be loose. Securing the connector resolved the code.

When the Usual Fixes Don't Work

• While the most common fix documented in TSBs is a PCM software update, real-world owner reports confirm that if the flash does not work, the next most likely cause is a failed Engine Oil Temperature sensor itself, which can be replaced as a DIY job with a special socket. In other cases, a simple loose connector near the oil filter after service has been the root cause.

OEM Part Supersession History

• 68119586AA → 68088241AA — Standard part revision or manufacturer change.
  Heads up: The new part number (68088241AA) is the correct replacement for the original. Using old stock of 68119586AA is not recommended.

Model Year Variations Within This Range

• 2013: The 2013 model year introduced the Fiat 500 Turbo model, which featured a 135hp turbocharged engine with twin intercoolers. While the P0298 TSBs apply to both turbo and non-turbo engines, the presence of the turbo and its associated cooling components (including an oil cooler) on more models adds diagnostic steps if an actual mechanical overheating condition is suspected.