Symptoms
Symptoms of a DTC P2182 code can range from nothing more than the illumination of the “check engine” light to one or more of the following:
- The MIL (Malfunction Indicator Lamp) will always illuminate
- The vehicle may be hard to start
- May blow a lot of black smoke and run extremely rich
- The engine may want to die or backfire through the exhaust pipe
- The engine may idle roughly and increased NOx emissions may be apparent (requires a gas analyzer)
- Cooling fans may run all the time when they shouldn’t, or not at all when they should
Causes
Usually, the cause can be attributed to a faulty ECT sensor, but this doesn’t rule out the following:
- Damaged wiring or connector to ECT sensor #2
- Open or short circuit in the reference or signal circuit
- Open or short circuit in the ECT #2 signal circuit
- Faulty PCM
Possible Solutions
1. Visually inspect ECT sensor #2 for any damage to the wiring or connector and repair if necessary. Then, if you have access to a scanner, determine what the engine temperature is. (If you don’t have access to a scan tool, using the dashboard temperature gauge may not be an effective way to determine coolant temperature. This is because code P2182 refers to ECT SENSOR #2, and the dashboard gauge is typically operated by a single-wire SENDER. Basically, a different sensor that the code does not refer to.)
2. If the engine temperature is abnormally high, around 280 degrees F, that’s abnormal. Disconnect the sensor from the engine and see if the signal drops to, say, negative 50 degrees. If it does, then it’s highly likely that the sensor is faulty, internally shorted, causing it to send a low-resistance signal to the PCM. However, if you want to be sure it’s the sensor and not the wiring, you can perform a few tests. With the ECT sensor disconnected, check that you have 5 volts on the reference circuit with KOEO (Key On Engine Off). You can also check the sensor’s resistance to ground using an ohmmeter. The resistance of a normal sensor to ground will vary somewhat by vehicle, but basically, if the engine temperature is around 200 degrees F, the resistance will be around 200 Ohms. If the temperature is around 0 degrees F, the resistance will be over 10,000 Ohms. With this test, you should be able to determine if the sensor’s resistance matches the engine temperature. If it’s not accurate based on your engine’s temperature, you likely have a faulty sensor.
3. Now, if the engine temperature according to the scanner is around 280 degrees F and disconnecting the sensor doesn’t cause the reading to drop to negative 50 degrees F, but it stays at the same high-temperature reading, then you’ll need to repair the short circuit on the signal circuit (ground) to the PCM. It’s shorted directly to ground somewhere.
4. If your engine temperature reading according to the scanner shows negative 50 degrees F or so, (and you don’t live in the Arctic!) disconnect the sensor and check for a 5V reference present at the sensor.
5. If there isn’t one, check at the PCM connector for the proper 5V reference. If it’s present at the PCM connector, repair the open or short in the 5V reference from the PCM. If there is no 5V reference present at the PCM connector, then you’ve completed your diagnosis and you may have a faulty PCM. 6. If the 5V reference circuit is intact, check the ground signal to the PCM using the previous ground resistance test. If the resistance isn’t normal for the engine temperature, measure the resistance of the ground signal wire to the PCM by removing the ground signal wire from the PCM connector. The wire should have no resistance when disconnected from the PCM to the sensor. If it does, repair the open signal to the PCM. If there’s no resistance on the ground signal wire and the sensor resistance test is normal, then suspect a faulty PCM.