P2184 ECT Sensor # 2 Circuit Low Input
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P2184 ECT Sensor # 2 Circuit Low Input
OBD-II DTC Datasheet
Low input signal in the sensor circuit No. 2 engine coolant temperature (ECT)
What does this mean?
This Diagnostic Trouble Code (DTC) is a generic transmission code, which means it applies to all vehicles since 1996 (Honda, Toyota, Volkswagen VW, Mazda, Dodge, Ford, BW, etc.). Although general in nature, the specific repair steps may differ depending on the brand / model.
The ECT (engine coolant temperature) sensor is a thermistor located in the engine block or other coolant passage. It changes resistance as the temperature of the coolant it comes in contact with changes. Usually this is a two-wire sensor. One wire is the 5V reference from the PCM (Powertrain Control Module) and the other is the ground from the PCM.
When the coolant temperature changes, the resistance of the sensor changes. When the engine is cold, the resistance is great. When the engine is warm, the resistance is low. If the PCM detects that the signal voltage is lower than the normal operating range of the sensor, then a code P2184 will be set.
Example of an ECT engine coolant temperature sensor
Note. This DTC is basically the same as P0117, however the difference with this DTC is that it relates to ECT # 2 sensor circuit. Therefore, vehicles with this code mean they have two ECT sensors. Make sure you are diagnosing the correct sensor circuit.
symptoms
Possible symptoms include:
- MIL Illumination (Malfunction Indicator)
- Poor fuel economy
- Poor handling
- The engine may run intermittently or emit black smoke from the exhaust pipe.
- Can't stand idle
- Can start and then die
reasons
Possible causes of a P2184 code include:
- Defective sensor # 2 ECT
- Short to ground in ECT signal circuit # 2
- Defective or damaged connectors
- Damaged wire harness
- Loose terminals on ECT or PCM
- POSSIBLY overheated engine
- Bad PCM
Possible solutions
Because this code is for an abnormally low PCM signal from ECT sensor # 2, the PCM has detected an excessively hot condition in the engine coolant. This could be due to a faulty ECT sensor or wiring, but possibly due to engine overheating. Therefore, if your engine is overheated, diagnose it first. Having said that, here are the possible solutions:
Using a scan tool with KOEO (Engine Off Key), check the ECT sensor # 2 reading on the display. On a cold engine, the ECT reading should match the IAT (Intake Air Temperature) sensor. If not, replace the # 2 ECT sensor.
1. If the ECT reading shows an excessively high temperature, for example, more than 260 degrees. F, then disconnect the coolant temperature sensor. This should cause the ECT reading to drop to extremely low values (about -30 degrees Fahrenheit or so). If so, replace the sensor because it is shorted internally. If this does not change the reading, check for a short to ground in the ECT wiring signal circuit. It is possible that the two ECT wires are shorted to each other. Look for frayed or melted wiring. Repair if necessary.
A. If you can't find any wiring problems and the ECT reading doesn't drop to its lowest readings when unplugged, then check for voltage coming out of the PCM at the signal wire pin on the PCM connector. If there is no voltage or it is low, the PCM may be faulty. NOTE. On some models, a temporary short circuit of the 5 Volt reference signal is possible. This can happen if the motor sensor internally shorts the 5V reference. Since the 5V reference is a "common" circuit on many models, this will cause it to be abnormally low. This is usually accompanied by several other sensor codes. If you suspect this may be the case, unplug each sensor until the 5 volt reference voltage reappears. The last sensor disabled is the fault sensor. Replace and recheck signal wire from PCM connector
2. If the scan tool ECT reading appears normal at this time, the problem may be intermittent. Use the wiggle test to manipulate the harness and connectors while observing the scan tool ECT reading. Repair any wiring or connectors that are loose or corroded. You can check freeze frame data if your scan tool has this function. When it fails, it will show ECT reading. If it shows the reading is at its highest level, replace the ECT sensor and see if the code reappears.
Corresponding ECT sensor circuit codes: P0115, P0116, P0117, P0118, P0119, P0125, P0128, P2182, P2183, P2185, P2186
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