P1115
ChryslerEngine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage/IAT - B Circuit High Input
Medium SeverityThis code indicates an intermittent high voltage signal from the Engine Coolant Temperature (ECT) sensor or the Intake Air Temperature (IAT) sensor B circuit. This typically means the engine computer is receiving a signal suggesting the engine or intake air is much colder than it actually is, leading to incorrect fuel mixture adjustments.
⚠️ Before You Begin (Safety First)
Always allow the engine to cool completely before working on any components related to engine coolant. Exercise caution when working around electrical connections; it's always safest to disconnect the battery before performing any electrical inspections or repairs to prevent accidental shorts or shocks.
Common Symptoms
- Check Engine Light illuminated
- Poor fuel economy
- Rough idle
- Hard starting, especially when cold
- Engine running rich (excessive fuel)
- Engine running lean (insufficient fuel)
- Increased emissions
Common Causes
- Faulty Engine Coolant Temperature (ECT) sensor
- Faulty Intake Air Temperature (IAT) sensor
- Corroded or loose electrical connections at the sensor or harness
- Open circuit or short to voltage in the ECT or IAT sensor wiring harness
- Faulty Powertrain Control Module (PCM), though less common
Frequently reported on: Chrysler Town & Country 2008-2010, Dodge Grand Caravan 2008-2010, Jeep Grand Cherokee 2007-2009, Chrysler 300 2005-2007, Dodge Charger 2006-2008
Diagnostic Steps
- Locate the Engine Coolant Temperature (ECT) sensor and the Intake Air Temperature (IAT) sensor. Refer to your vehicle's service manual for exact locations.
- Visually inspect the wiring harnesses and connectors for both sensors. Look for any signs of damage, fraying, corrosion, or loose connections.
- Carefully disconnect the electrical connector from the suspected sensor (either ECT or IAT). Check for bent pins or corrosion inside the connector.
- If comfortable with a multimeter, test the resistance of the sensor and compare it to the manufacturer's specifications for various temperatures. A high resistance reading, especially when the engine is warm, could indicate a faulty sensor.
- Clear the P1115 code using an OBD-II scanner and test drive the vehicle to see if the code returns.
- If the code returns and visual inspection and basic testing point to a faulty sensor, replace the affected sensor with a new, OEM-quality part.
👨🔧 When to Call a Professional
While replacing a sensor is often a straightforward DIY task, if you've replaced the sensor and the code persists, or if visual inspection reveals no obvious wiring issues, it's time to consult a professional technician. They can perform advanced electrical diagnostics to rule out issues with the PCM or complex wiring harness problems.
Commonly Asked Questions
What specifically does P1115 mean for my Chrysler?
P1115 for Chrysler vehicles specifically points to an intermittent high voltage issue in either the Engine Coolant Temperature (ECT) sensor circuit or the Intake Air Temperature (IAT) sensor 'B' circuit. This usually means the computer is getting a signal that the engine or intake air is much colder than it actually is.
Can I drive my car with a P1115 code?
While you can typically drive with this code, it's not recommended for long periods. Incorrect temperature readings can cause the engine to run too rich or too lean, leading to poor fuel economy, increased emissions, and potential long-term damage to components like the catalytic converter.
How do I determine if it's the ECT or IAT sensor causing the P1115 code?
You can try disconnecting one sensor at a time to see if the code changes or if a different related code appears. A more accurate method involves using an OBD-II scanner to view live data for both the ECT and IAT sensors. Look for readings that seem illogical or frozen compared to actual engine conditions.
What tools will I need to fix this code?
Basic tools typically include an OBD-II scanner to read and clear codes, a socket or wrench set for sensor removal/installation, and potentially a multimeter for electrical testing. A service manual for your specific Chrysler model can also be very helpful.
Why is my Check Engine Light still on after replacing the sensor?
After replacing a faulty sensor, you must clear the P1115 code using an OBD-II scanner. If the light remains on or the code returns after clearing, it indicates that the sensor was not the sole issue, and further diagnosis of the wiring or the PCM is required.
Does P1115 always mean a bad sensor?
Not necessarily. While a faulty sensor is common, P1115 can also be caused by issues within the sensor's wiring harness, such as an open circuit, corrosion, or a poor electrical connection. Less commonly, it could indicate a problem with the Powertrain Control Module (PCM).