P0118 on 2009-2020 Dodge Journey: Causes, Symptoms, and Fixes

What's Unique About the 2009-2020 Dodge Journey

The Dodge Journey was produced for a single generation with several engine options, primarily the 2.4L 4-cylinder 'World Engine' and the 3.6L V6 'Pentastar'. The cause of P0118 is almost always the same across these engines—a failed sensor or wiring—but the sensor's location differs. On the 3.6L V6, the sensor is located on the front of the engine, near the cooling fan assembly. On the 2.4L 4-cylinder, it is on the driver's side of the engine in the water outlet housing. 🎬 Watch a 4-cylinder coolant temperature sensor replacement walkthrough. For some 2.4L models, a Technical Service Bulletin (TSB 05-002-12) exists, noting that the brake booster vacuum hose could rub against and damage the ECT sensor's wiring, making a visual inspection of that specific area a critical first step.

Symptoms You May Notice

• Check Engine Light is on
• Cooling fans running constantly at high speed, even when the engine is cold
🎬 See why your radiator fan won't turn off.
• Inaccurate or non-functional temperature gauge on the dashboard (may read cold or show no reading)
• Engine running rough, hesitating, or stalling, especially when cold
• Decreased fuel economy due to the PCM defaulting to a rich fuel mixture
• Difficulty starting the engine
• Black smoke from the exhaust on startup

Most Likely Causes

1. Faulty Engine Coolant Temperature (ECT) Sensor 🔴 High Probability → Shop Engine Coolant Temperature Sensor Sensors are electronic components that can fail over time due to extreme heat cycles and age. An internal open circuit within the sensor is a common failure mode leading to a P0118 code.
   How to confirm: With a scan tool, check the live data for the ECT sensor. If it reads an impossibly low temperature (like -40°F) when the engine is at ambient temperature, the sensor is the primary suspect. You can also test the sensor's internal resistance with a multimeter; an open circuit (infinite resistance) confirms failure. A healthy sensor should have a resistance of approximately 2,500 Ohms at room temperature (20°C / 68°F).
   Typical fix: Replace the ECT sensor. This usually involves draining a small amount of coolant, unplugging the old sensor, unscrewing it, and installing the new one.
   Est. part cost: $15-$40
2. Damaged Wiring or Connector 🟡 Medium Probability For 2.4L engines, TSB 05-002-12 specifically calls out that the brake booster vacuum hose can rub against the ECT connector, causing chafing and damage to the wires. General corrosion, bent pins, or a broken locking tab on the connector can also cause a poor connection.
   How to confirm: Visually inspect the wiring harness and connector for signs of damage, corrosion, or looseness. Pay special attention to the area near the brake booster hose on 2.4L models. Wiggle the connector while watching the live data on a scan tool; if the reading flickers, you have a bad connection.
   Typical fix: Repair the damaged section of wire or replace the connector pigtail.
   Est. part cost: $10-$25
3. Open Circuit ⚪ Low Probability
   How to confirm: Test for 5V reference and ground at the sensor connector using a multimeter. If either is missing, trace the wiring back to the PCM to find the break. Shorting the two pins in the harness-side connector with a jumper wire should cause the scan tool reading to jump to a very high temperature (e.g., 250-300°F); if it doesn't, the wiring is faulty.
   Typical fix: Find and repair the break in the wire.
   Est. part cost: $5-$15

Rare But Worth Checking

• Faulty Powertrain Control Module (PCM): This is extremely rare. The PCM should only be considered after all other possibilities (sensor, wiring, connections) have been exhaustively tested and ruled out. A faulty PCM driver can fail to correctly interpret the sensor's signal.

Diagnosis Steps

1. Connect an OBD-II scanner and confirm P0118 is the active code.
2. View live data on the scanner. Look at the Engine Coolant Temperature reading. A reading of -40°F or another extreme low value points directly to this circuit.
3. Turn the engine off. Visually inspect the ECT sensor and its connector for obvious damage, corrosion, or loose wires. On 2.4L models, pay close attention to the area near the brake booster vacuum hose, per TSB 05-002-12.
4. Unplug the sensor. The scan tool reading should remain at -40°F. Use a jumper wire to connect the two terminals in the wiring harness connector. The scan tool reading should now jump to a very high temperature (e.g., 284°F+).
5. If the reading jumps to high as expected, the wiring and PCM are good. The problem is a faulty ECT sensor. Replace it.
6. If the reading does not change when the terminals are jumped, there is an open in the signal or ground wire between the connector and the PCM, or a faulty PCM (rare).
7. After repair, clear the code and test drive to ensure the fix was successful and the temperature gauge reads normally.

Parts You'll Likely Need

• Engine Coolant Temperature (ECT) Sensor (OEM #Mopar 5149077AB (Fits many 3.6L and 2.4L applications)) — This sensor is the most frequent point of failure for code P0118, as it is an electronic component exposed to constant heat cycles.
  Trusted brands: Mopar, Standard Motor Products (SMP), Delphi, NTK
  OEM price range: $45-$70
  Aftermarket price range: $15-$40
• ECT Sensor Connector Pigtail — Needed if the original connector is corroded, melted, or has broken locking tabs or wires, especially on 2.4L models where rubbing from the brake booster hose can occur.
  Trusted brands: Dorman, Mopar
  OEM price range: $20-$35
  Aftermarket price range: $10-$25

Technical Service Bulletins (TSBs) & Recalls

• 05-002-12: Notes potential for brake booster vacuum hose to damage ECT sensor wiring on 2011 2.4L models, causing P0117 or P0118.

Platform-Specific Known Issues

• TSB 05-002-12 for 2011 Dodge Journey 2.4L models indicates that the brake booster vacuum hose may be routed too close to the ECT sensor, causing damage to the connector or wiring and triggering P0117 or P0118 codes. Owners should inspect this area carefully before replacing any parts.

Mechanic-Grade Diagnostic Values

• ECT Sensor Resistance vs. Temperature — expected: Approx. 100,000Ω at -40°C (-40°F), 2,500Ω at 20°C (68°F), 300Ω at 80°C (176°F), 180Ω at 100°C (212°F).. Failure: Infinite resistance (open circuit) or a reading that does not change with temperature indicates a failed sensor.
• ECT Sensor Connector Voltage (Key On, Engine Off) — expected: One pin should have a 5-volt reference from the PCM; the other is the ground return.. Failure: Absence of the 5V reference points to a wiring or PCM issue. Absence of ground points to a wiring issue.

Wiring & Ground Locations

• ECT Signal at PCM (2.4L Engine) — Pin 20 of the C2 connector (Black/Orange) at the Powertrain Control Module. The wire is typically Tan with a Black stripe.. Allows for continuity testing of the signal wire directly from the PCM, bypassing the rest of the harness to isolate a break.
• ECT Signal at PCM (3.6L Engine) — Pin 12 of the C2 connector at the Powertrain Control Module. The wire is typically Violet with an Orange stripe.. Allows for continuity testing of the signal wire directly from the PCM, which is crucial for differentiating a wiring fault from a sensor failure.
• G903 (Sensor Ground) — For 3.6L engines, this ground point is located on the top of the transmission. For 2.4L engines, it is on the left rear of the engine.. This is a primary grounding point for engine components. A corroded or loose connection at G903 can cause an open or high resistance on the sensor's ground side, directly leading to a P0118 code.

Real Owner Repair Stories

• YouTube Channel 'Electrical Car Repair LIVE' (Dodge Journey with 3.6L V6 engine, model year within 2009-2019 range.) — Check Engine Light on, radiator fan running constantly, and temperature gauge not working.
  ❌ Tried (didn't work) The video proceeds directly to diagnosis, not mentioning prior failed attempts.
  ✅ What actually fixed it Diagnosis with a scan tool showed an engine coolant temperature of -40°F. The ECT sensor was identified as the faulty component. Replacing the ECT sensor and clearing the codes resolved all symptoms, with the scan tool then showing a normal temperature reading.

OEM Part Supersession History

• 5149096ab → 5149077AB — Standard part update/revision by Mopar.

Model Year Variations Within This Range

• 2011 (specifically): TSB 05-002-12 was issued for 2011 2.4L models regarding the brake booster vacuum hose potentially chafing the ECT sensor wiring harness, causing P0117 or P0118. While possible on other years, it was officially documented for 2011.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Cracked/Leaking Oil Filter Housing (3.6L V6) 🔴 High — Very common, typically occurs between 60,000-120,000 miles. Can cause major oil and/or coolant leaks.
• Premature Brake Wear 🟠 Medium — Extremely common on 2009-2012 models, with owners reporting replacement of pads and rotors as early as 12,000-20,000 miles. Less frequent on later models with upgraded brake components. (Ref: Warranty extension was offered for early models, but no formal recall.)
• Transmission Issues (62TE 6-Speed) 🟠 Medium — Reports of harsh shifting, shuddering, or solenoid pack failure are common. Regular fluid changes every 25,000-30,000 miles are critical.
• Electrical Problems (WIN Module / Key Fob) 🟡 Low — Common reports of the vehicle not starting or the remote keyless entry failing to work. Often traced to the Wireless Ignition Node (WIN) module needing a software update or replacement. (Ref: Recall R61 for some models related to ignition switch.)
• Water Leaks into Cabin 🟠 Medium — Frequently reported on earlier models (2009-2012), often from clogged sunroof drains, bad door seals, or improperly sealed firewall grommets.
• Faulty Throttle Body (2.4L) 🟠 Medium — Failure is common, leading to stalling or limp mode. Often triggers codes like P2110 or P2112.

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: For this repair, a used part is only recommended for the connector pigtail if it needs to be replaced. A junkyard pigtail with a few inches of wire can be spliced in to fix a damaged connector.

Donor-vehicle mileage cap: roughly under 150000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• For a connector pigtail, inspect for any signs of melting, cracking, or brittleness.
• Ensure the locking tab is intact and functional.
• Check that the wire insulation is not frayed or exposed.
• Avoid connectors from vehicles with obvious signs of engine fire or severe front-end damage.

Aftermarket brands forum-validated for this vehicle:

• Standard Motor Products (SMP)
• Delphi
• NTK

Brands owners have reported issues with on this vehicle:

• No-name, ultra-low-cost sensors from online marketplaces are frequently reported on forums as being inaccurate or failing prematurely.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• P0117 — Engine Coolant Temperature Sensor Circuit Low Input. This is the direct companion code to P0118. It can be caused by the same wiring harness issue noted in TSB 05-002-12, but indicates a short circuit rather than an open circuit.
• P0172 — System Too Rich (Bank 1). The P0118 fault makes the PCM believe the engine is extremely cold, causing it to inject excess fuel. This prolonged rich condition can trigger a P0172 code.
• P0175 — System Too Rich (Bank 2). On V6 models like the 3.6L Journey, this code may appear alongside P0172 for the same reason: the PCM is commanding a rich fuel mixture based on the erroneous -40°F temperature reading from the faulty ECT circuit.
• P0300 — Random/Multiple Cylinder Misfire. The excessively rich fuel mixture caused by the P0118 fault can lead to poor combustion, spark plug fouling, and engine hesitation, which may be severe enough to set a general misfire code.

Frequently Asked Questions