P2742 OBD Error Code: Problem & Solutions

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Error code P2742 flashing? Well, this is how you can diagnose the error code P2742. This OBD-II code transmission may not shift properly is also referred to as a transmission fluid temperature sensor "B" circuit low. The engine control module (ECM) is informed by the transmission fluid temperature sensor about the temperature of the fluid in the transmission. The PCM sets the code as soon as it detects a wrong signal from the transmission temperature sensor

In order to determine the shift points, line pressure and torque converter clutch control (TCC) the transmission fluid temperature sensor (TFT) sensor creates a signal that is utilized by the powertrain control module (PCM). Often, this sensor can be found in the transmission oil pan. The PCM supplies the TFT sensor a reference voltage (usually 5 volts). For sending a return voltage signal to the PCM, it changes its internal resistance in relation to transmission fluid temperature. It should be noted that the TFT sensors are a kind of negative temperature coefficient (NTC). The internal resistance of the sensor shares an inverse relation to the oil temperature. So, when the TFT sensor signal voltage falls down, the transmission fluid temperature tends to rise and vice versa.

What causes this problem with the Transmission Fluid Temperature Sensor "B" Circuit Low?

• Malfunctioning transmission fluid temperature sensor
• Transmission defects
• Wiring issues
• Failed PCM

1. Transmission Fluid Temperature Sensor - Erratic shifting? An inoperative transmission? All this is caused due to your malfunctioning transmission fluid temperature sensor. Tune into Parts Avatar if you want all these problems to end.
2. Powertrain Control Module - A failed PCM? Do you have any idea about the extent to which it can damage your system? A faulty powertrain control module brings along issues like a malfunction in the functioning of the entire engine, also the sparks and ignition timing from the spark plugs are controlled and received by the PCM. Tune into Parts Avatar if you want to get your error code fixed.
3. Transmission Control Module - An error in this essential unit can lead to a big loss. It not only triggers the error code P2742 but also problems like engine stalls and a rough idle. Now get your TCM changed or repaired with Parts Avatar. Tune in now!
4. Engine Control Module - Having problems with you ECM? Well, this can stimulate problems like harsh or delayed shifting too. Repair or replace now in order to avoid further problems caused by the error code P2742.
5. Diagnostic Tools - Do you know for a fact that how essential it is to have an access to premium quality diagnostic tools as they help greatly while performing the diagnosis procedure? So, to get your hands on some of them, log into Parts Avatar for your premium quality tools.

If you are facing OBD error code P2742, then there are significant common symptoms that can be felt or observed. We have worked out a list here to help you out in understanding this problem better:

Common Symptoms

• The check engine light flashing
• Bad torque converter clutch operations
• Harsh or delayed shifting may be observed
• Limp-mode on

Have a look at some ways with which you can correct the P2742 code:

• Make sure you repair or replace all the transmission defects present in the system
• Mend or restore a malfunctioning powertrain control module
• A damaged transmission fluid temperature sensor should be replaced or repaired right away
• All the wiring problems should be mended or restored

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If you want to easily diagnose this fault code, then all you have to do is to follow the steps which are mentioned below:

It can be observed that the automatic transmission has one or more temperature sensors (usually two-wire variable resistance sensors) that perform the function of providing the PCM with data. This sensor has a voltage wire (generally it is a 5-volt reference signal) and a ground wire. This reference voltage wire is used by the PCM to control the transmission temperature. The sensor resistance decreases and reference voltage increases as soon as the transmission temperature increases. Also, when the sensor resistance is high and the transmission is cool, the driving reference voltage to the PCM is down. The PCM reacts in accordance to the input reference voltage readings as transmission temperature. A code is set and a service engine soon light is illuminated when the transmission temperature is excessive. A low or substandard transmission fluid condition should be suspected if the transmission over temp code is set and the engine is not overheating.

Perform a thorough diagnosis. All the transmission leaks should be restored and the transmission should be filled with the correct amount and type of fluid (if in case, the fluid has a "burnt" odor, and you are experienced and trained enough to identify it, you may go ahead and blame the transmission). Then operate and recheck the transmission. Although, it should be noted that the leaks that start from the front seal (behind the torque converter) most likely need complete removal of the transmission. At such times, you may want to consider a transmission restoration, if the mileage dictates. Also, if the transmission functions well and doesn't overheat, a failed transmission temperature sensor should be suspected. Numerous tools are instrumental in successfully diagnosing the conditions that contribute to this code being stored. Start with using a suitable OBD-II scanner (or code reader) and a digital volt/ohmmeter to perform a successful diagnosis. Acquire a manufacturer's wiring schematic as this will also prove to be important to successfully diagnose this code. Then, a careful visual inspection should be performed of all the PCM wiring and connectors. Then mend or restore all the defective, loose, shorted, or corroded wiring, connectors and parts. Also, we advise you to always retest the system after repairs have been performed to ensure success. Then, if all the system wiring, connectors and parts (including fuses) are functioning in order, the scanner (or code reader) should be connected to the diagnostic connector for recording all stored codes and freeze frame data. Store this information as it can be extremely helpful in diagnosing intermittent conditions that may have added to this code being stored. Then, continue by clearing the codes. Operate the vehicle to see if the code returns. This is extremely helpful to determine whether or not the error is intermittent. Test drive the vehicle to see if the code returns, after the repairs have been made. If the code fails to return, you may have an intermittent condition. These intermittent conditions often prove to be quite tough to diagnose and in extreme cases may have to be allowed to worsen before a precise diagnosis can be [performed. Next, unplug the electrical connector from the transmission temperature sensor for testing the reference voltage. Generally, this is a 5-volts but refer to the manufacturer's service manual for assurance. If in case, there is a 5-volt signal present with the ignition turned to the run position, check the sensor ground wire immediately. Probe the sensor resistance using the manufacturer's temperature to resistance chart, if both the reference signal and the ground signal are present. Lastly, analyses your findings to the manufacturer's specifications. Replace the sensor if it fails to match. Disconnect the PCM electrical connector and test circuit continuity and resistance between the sensor and the PCM, if the sensor and voltage at the sensor are within required specifications. Retest the system after all the required repairs of the circuitry and parts have been performed. If all of it is working in order, suspect a defective PCM (although, PCM failure is rare and PCM replacement will require reprogramming).

Common Mistakes When Diagnosing The P2742 Code

Here we have listed a few common mistakes that should be avoided:

• A failed powertrain control module (PCM)
• Faulty transmission control module (TCM)
• Malfunctioning transmission temperature sensor
• Wiring issues