P2184 OBD-II Trouble Code: Engine Coolant Temperature Sensor 2 Circuit Low

Our certified mechanics come to you · Get a fair and transparent estimate upfront


Cost of diagnosing the P2184 code

P2184 is a diagnostic trouble code (DTC) for "Engine Coolant Temperature Sensor 2 Circuit Low". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
SCHEDULE P2184 DIAGNOSTIC Get a fair and transparent estimate upfront

P2184 code definition

P2184 is an OBD-II generic code for the engine control module (ECM) detecting the engine coolant temperature sensor (ECT) #2 is indicating low range and does not correlate with ECT sensor #1.

What causes the P2184 code?

  • The engine control module (ECM) checks the ECT and ambient temperature sensors when the engine is first started cold to see if the sensors correlate with each other and with the ambient air temperature sensor.

  • The ECT sensor is not reading within a specified range and is too low when compared to the other sensors.

  • The ECT sensor is too low and is not correlating to the #1 ECT sensor reading and the ambient temperature sensor.

What are the symptoms of the P2184 code?

  • The Check Engine Light will be illuminated and the code is set in the ECM memory as a fault.

  • The ECM will ignore the ECT #2 sensor and will retest it each time the engine has a cold start to verify the failure is still active or not.

  • The engine should run normally as long as the #1 sensor is not having a problem and correlates to the ambient air temperature sensor.

  • The only symptom will be the Check Engine Light not being on as long as only one sensor is failing.

How does a mechanic diagnose the P2184 code?

  • Scans for codes and documents the code in the ECM and looks at the freeze frame data for failure

  • Scans the engine only after the engine has been sitting for at least 8 hours and the coolant is at ambient temperature

  • Scans the ECM and checks readings from the two ECT sensors and the ambient air temperature sensor to see if the ECT #2 sensor is reading a lower temperature than the other two sensors. All three should be within a few degrees of each other

  • Checks the #2 ECT sensor connector for problems like loose or corroded pins

  • Replaces the #2 ECT sensor if all wiring checks out okay and the Ohm's test shows that it is out of specifications

Common mistakes when diagnosing the P2184 code

  • Clearing ECM memory codes before checking the freeze frame data for the main failure problem, so the failure may be duplicated and repaired

  • Failing to clear the ECM codes after the codes are fixed so the ECM will be able to monitor the system like normal again

  • Failing to identify and repair any connector issues before replacing the ECT sensor

How serious is the P2184 code?

  • Code P2184 is a code indicating the number 2 ECT sensor does not match the #1 sensor, and if this sensor fails, then the engine will have running issues. This will fail the vehicle for emissions testing and cause the engine to run too rich during the failure.

What repairs can fix the P2184 code?

Additional comments for consideration regarding the P2184 code

Code P2184 is for the second ECT sensor. The engine has two sensors to back up each other in case of a failure to keep the engine running smoothly. This is so that one failure does not cause any running issues with the engine except for turning on the Check Engine Light.

Failure to fix the problem will keep the Check Engine Light on, and if another fault happens, you would not be alerted to an issue since the Check Engine Light would already be on. In addition, this failure will cause your vehicle to not pass your emission testing in most states and would need to be repaired before retaking the test.

Need help with a P2184 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

trouble codes
Check Engine Light

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P2184 code.

Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

YourMechanic Check Engine Light is on Inspection Service

Average Rating


Number of Reviews


Rating Summary


6 years of experience
18 reviews
6 years of experience
Jeep Grand Cherokee - Check Engine Light is on - Carmichael, California
Anthony was great! We are very happy that we chose to go with this company instead of the overpriced and slow service we get from the Jeep dealership. He was on time and did the job just as expected. He identified a couple of other things that need to be done before the problems get worse. We appreciate having a technician give us direct feedback regarding our vehicle, rather than a service advisor (salesperson) that we've had to deal with in the past at the dealership. We'll be booking the addtional services very soon and will definitely request Anthony again now that he is familiar with our vehicle!


37 years of experience
113 reviews
37 years of experience
Subaru Forester - Check Engine Light is on - Santa Fe Springs, California
Michael was punctual and courteous. He knows what he’s doing and I would absolutely recommend him to anyone.


6 years of experience
18 reviews
6 years of experience
BMW 740Li - Check Engine Light is on - Roseville, California
Very helpful in finding out the fault codes in my bmw 740 li. It was simple fix and that the two tube hose just had to be connected and my drive train malfunction went away. This saved me from having to go the an expensive dealership. Anthony has a good attitude about his work.


19 years of experience
613 reviews
19 years of experience
Ram 1500 - Check Engine Light is on - Houston, Texas
Breck did a great job working on my truck. Showed up on time, found any issues I had on my truck and explained everything to me so that I understood what was going on. Went above and beyond, definitely will book him for future appointments.

Related questions

Engine fan non-stop running until you turn the ignition key off

A P2184 code indicates temp sensor circuit low. That means the voltage that the ECU reads on the temp sensor is low. The ECU interprets this as a hot engine and turns on the fan. A short circuit in the...

More related articles

P0183 OBD-II Trouble Code: Fuel Temperature Sensor A Circuit High Input
P0183 code definition Fuel Temperature Sensor A Circuit High Input What the P0183 code means P0183 is a generic OBD-II code indicating...
P2089 OBD-II Trouble Code: A Camshaft Position Actuator Control Circuit High Bank1
P2089 P2089 code definition A Camshaft Position Actuator Control Circuit High Bank1 What the P2089 code means The P2089 code means that the A camshaft position actuator was found to have high voltage. The vehicle’s electronic control unit (ECU) detects...
P0740 OBD-II Trouble Code: Torque Converter Clutch Circuit Malfunction
P0740 P0740 Code Definition Torque converter clutch circuit malfunction is the technical definition of this trouble code What the P0740 code means What the P0740 code means is that the powertrain control module (PCM) has detected something unusual within the...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com