P1185 on 2016-2017 Fiat 500X: General Pressure Sensor Correlation Causes and Fixes

What's Unique About the 2016-2017 Fiat 500X

For the 2016-2017 Fiat 500X and its platform-mates like the Jeep Renegade, Chrysler 200, and Dodge Dart, this code is exceptionally well-documented by the manufacturer. The issue is frequently not a hardware failure but a logic flaw in the original PCM software. Fiat-Chrysler Automobiles (FCA) released several Technical Service Bulletins (TSBs) to address this and other related codes with a single software update, making a trip to the dealer for a reflash a common and official fix.

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 is on
• Rough idle, especially on a cold start
• Reduced engine power and acceleration
• Poor fuel economy
• Vehicle may hesitate or stumble under load

Most Likely Causes

1. Outdated Powertrain Control Module (PCM) Software 🔴 High Probability Manufacturer TSBs #08-010-16 (Revisions B, C, and D) and #18-011-17 REV. B explicitly list P1185 as a code that can be resolved with a software update. This indicates the original software logic was overly sensitive or flawed, a known issue across the 2.4L MultiAir engine platform.
   How to confirm: Contact a Fiat dealership or a qualified shop with access to OEM service information. They can check your vehicle's VIN to see if the software updates from the relevant TSBs have been applied. The dealer uses a wiTECH scan tool to compare the current software ID to the latest version.
   Typical fix: A technician will use a proprietary scan tool (like wiTECH) to reflash the PCM with the updated software. This is typically a labor-only procedure and may cost between $100-$250 depending on dealer labor rates.
   Est. part cost: $0
2. Faulty Manifold Absolute Pressure (MAP) Sensor 🟡 Medium Probability The MAP sensor is the primary hardware component involved in this correlation check. It is exposed to constant pressure and temperature changes within the intake manifold, making it a common failure point. On the 2.4L engine, its location on the rear of the intake manifold makes it difficult to access.
   How to confirm: Using a scan tool, compare the MAP sensor reading to the BARO sensor reading with the Key On, Engine Off (KOEO). They should be nearly identical (within ~1.0 psi). If the MAP reading is skewed, the sensor is likely faulty. You can also test the sensor's voltage output; it should change smoothly as vacuum is applied.
   Typical fix: Replace the MAP sensor. It is located on the back of the intake manifold, which can be challenging to reach.
   Est. part cost: $40-$90
3. Damaged Wiring or Loose Connector for MAP Sensor ⚪ Low Probability The wiring harness for the MAP sensor can sometimes come loose from its retainers and get damaged by the nearby serpentine belt. Connectors can also become brittle and break, leading to a poor connection.
   How to confirm: Visually inspect the MAP sensor connector for a tight fit and check the wiring harness for any signs of chafing, melting, or breaks, especially near the accessory belt. Check for 5V reference, ground, and a signal wire at the connector with a multimeter.
   Typical fix: Repair the damaged section of the wiring harness and secure it properly. If the connector is damaged, a new pigtail connector will need to be spliced in.
   Est. part cost: $15-$50

Rare But Worth Checking

• Major Vacuum Leak:

Diagnosis Steps

1. Check for TSBs: The first and most important step. Contact a Fiat dealer or qualified shop to determine if your vehicle needs the PCM software update specified in TSBs like #08-010-16 REV. D. If the update is needed and hasn't been performed, this is the most likely solution.
2. Scan for Other Codes: Check for accompanying codes like P0108, U1424, or P050D, which reinforce the diagnosis of a MAP/BARO correlation issue or a software problem.
3. Verify Sensor Readings: If the software is up to date, use a scan tool to view live data. With the Key On, Engine Off (KOEO), compare the 'MAP Sensor' and 'BARO Sensor' pressure readings. They should be within a few tenths of a pound per square inch (psi) or 1-2 kilopascals (kPa) of each other. If they differ significantly, proceed to hardware checks.
4. Inspect MAP Sensor Wiring: Turn the vehicle off. Locate the MAP sensor on the rear of the intake manifold. Inspect its electrical connector for looseness, corrosion, or damage. Trace the wiring harness as far as possible, looking for chafing, breaks, or heat damage, particularly near moving parts like the serpentine belt.
5. Test the MAP Sensor Circuit: If wiring looks okay, use a multimeter to test the connector. You should find a 5-volt reference wire, a ground wire, and a signal wire. A broken wire or bad ground can mimic a failed sensor.
6. Test the MAP Sensor: If the wiring and circuit are intact, the MAP sensor itself is the most likely culprit. Replacing it is the next logical step.
7. Check for Intake/Vacuum Leaks: Although less common for this specific code, a significant vacuum leak could theoretically cause pressure readings to be out of range. A smoke test can be performed to check the integrity of the intake system if all other steps fail to find the issue.

Parts You'll Likely Need

• Manifold Absolute Pressure (MAP) Sensor (OEM #68217630AA) — This is the most common hardware component to fail, causing the correlation error with the internal barometric sensor.
  Trusted brands: Mopar, Bosch, Standard Motor Products, Delphi
  OEM price range: $60-$100
  Aftermarket price range: $40-$90

Related Codes That Often Appear With This One

• P0108 — Stands for 'Manifold Absolute Pressure / Barometric Pressure Circuit High'. This code is directly related to a faulty MAP sensor and often appears with P1185.
• U1424-00 — Stands for 'Implausible Engine Torque Signal Received'. The PCM uses MAP sensor data to calculate engine torque, so an incorrect pressure reading can trigger this code. The TSB software update often resolves both codes simultaneously.
• P0335 — Stands for 'Crankshaft Position Sensor Circuit'. This code is also listed in the manufacturer TSBs alongside P1185 as being resolved by the same PCM software update.
• P050D — Stands for 'Cold Start Rough Idle'. This symptom-based code is directly linked to the issues caused by the pressure sensor correlation fault and is also addressed by the PCM software update.

Technical Service Bulletins (TSBs) & Recalls

• 18-011-17 REV. B: Lists P1185-00 - General Pressure Sensor Correlation as one of several DTCs that may be set.
• 08-010-16 REV. D: Lists P1185 - General Pressure Sensor Correlation as a DTC that may be present alongside others like U1424-00 and P0335, indicating a software update may be the solution.
• 08-010-16 REV. C: Also lists P1185 in a group of DTCs.
• 0801016: Lists P1185 in a group of DTCs.
• 08-010-16 REV. B: Lists P1185 in a group of DTCs.

Platform-Specific Known Issues

• A primary issue for the 2016-2017 Fiat 500X is that the original PCM software is overly sensitive or contains logic errors, leading to false P1185 codes. Fiat acknowledged this by issuing multiple TSBs (e.g., #08-010-16 REV. D, #18-011-17 REV. B) that bundle a fix for P1185 with fixes for other unrelated-seeming codes, all resolved via a software reflash.
• The 2.4L MultiAir 'Tigershark' engine is also known for excessive oil consumption issues, which can lead to other engine problems. While not directly causing P1185, maintaining the correct oil level is critical for the overall health of this engine.

Mechanic-Grade Diagnostic Values

• MAP Sensor 5V Reference Wire Voltage — expected: Approximately 5.0 Volts. Failure: A reading of 0V or significantly less than 5V points to a wiring issue or a problem with the PCM's 5V reference circuit.
• MAP Sensor Ground Circuit Voltage Drop — expected: Less than 0.1 Volts (100 millivolts). Failure: A reading higher than 0.1V indicates a poor ground connection, which can alter sensor readings.
• MAP Sensor Signal Wire Voltage (Key On, Engine Off) — expected: Approximately 4.5 - 5.0 Volts at sea level. Failure: A significantly lower or zero voltage reading suggests a faulty sensor or a short in the signal wire.
• MAP Sensor Signal Wire Voltage (Engine Idling) — expected: Approximately 1.0 - 1.5 Volts at sea level. Failure: Voltage that is too high at idle (e.g., above 2.0V) can indicate a vacuum leak or a faulty sensor that is not responding to engine vacuum.

Wiring & Ground Locations

• MAP Sensor Connector — On the rear of the intake manifold, near the firewall. It is often best accessed from underneath the vehicle.. This is the direct connection point for the MAP sensor. A loose, corroded, or damaged connector will cause an incorrect signal and trigger P1185. The wiring harness in this area is subject to heat and vibration.
• MAP Sensor Harness Retainers — Along the wiring harness path from the MAP sensor towards the main engine harness.. A technician noted that if these retainers are not reinstalled properly after service, the harness can come loose and get caught by the serpentine belt and water pump, causing wire damage and leading to sensor correlation codes.

Real Owner Repair Stories

• YouTube channel 'Electrical Car Repair LIVE' (2015 Dodge Dart (platform-mate with 2.4L MultiAir engine)) — Check Engine Light with code P1185.
  ❌ Tried (didn't work) The video narrator mentions that although the code can sometimes be misinterpreted as a fuel pressure issue, that was not the problem.
  ✅ What actually fixed it The problem was a faulty MAP sensor. Replacing the MAP sensor resolved the P1185 code.

Model Year Variations Within This Range

• 2016 vs 2017: For the 2017 model year, Fiat simplified the 500X lineup from five trims to three (Pop, Trekking, Lounge). The 2.4L engine, which was optional on some 2016 trims, became standard on the 2017 Trekking and Lounge models. While no major mechanical changes affecting this specific code are documented between the two years, the software updates mentioned in TSBs would apply to specific production date ranges, making a VIN check at a dealership crucial.