Technical Description of OBD-II Trouble Code
The circuit for the transmission fluid level sensor is experiencing low voltage.
What does that mean?
This particular diagnostic trouble code (DTC) is applicable to vehicles equipped with OBD-II that have a transmission fluid level sensor. Various vehicle makes, including but not limited to GM, Chevrolet, Ford, Dodge, Ram, Toyota, Hyundai, etc., may have this code, although it is not common.
The transmission fluid level (TFL) sensor is responsible for activating a warning light on the dashboard when the fluid level is low.
When the fluid level is within an acceptable range, the switch is connected to the ground. However, when the transmission fluid drops below a predetermined level, the switch opens and triggers a warning message of “low transmission fluid level” on the dashboard.
TFL sensors receive a reference voltage from the PCM. The PCM monitors the circuit and when it detects that the switch has opened, it activates the low fluid warning on the instrument cluster.
Code P070C is set when the PCM detects a low transmission fluid level sensor signal. This usually indicates a short circuit in the circuit. Other related codes include P070A, P070B, P070D, P070E, and P070F.
Code Severity & Symptoms
The severity of this transmission code ranges from moderate to severe. In some cases, this and related codes can indicate a low transmission fluid level, which, if not addressed promptly, can lead to transmission damage. It is advisable to address this code as soon as possible.
Symptoms of a P070C trouble code may include:
Common Causes Of This DTC Code
Possible causes for this code may include:
Diagnostic and Repair Procedures
Begin by checking the transmission fluid level and condition according to the manufacturer’s recommendations. Next, inspect the transmission fluid level sensor and its corresponding wiring. Look for loose connections, damaged wiring, etc. If any damage is found, repair it as necessary, clear the code, and observe if it reappears. Next, check for any technical service bulletins (TSBs) related to this issue. If no relevant information is found, you will need to proceed with a step-by-step diagnosis of the system.
The following is a general procedure, as the testing for this code may vary between vehicles. To accurately test the system, it is recommended to refer to the manufacturer’s diagnostic flow chart.
Check The Wiring
Prior to proceeding, consult the factory wiring diagrams to determine the identification of the wires. Autozone offers free online repair manuals for many vehicles, and ALLDATA offers single vehicle subscriptions.
Check the reference voltage side of the circuit
With the ignition on, use a digital multimeter set to DC volts to check for the presence of reference voltage (usually 5 or 12 volts) from the PCM. To do this, connect the negative meter lead to ground and the positive meter lead to the sensor B+ terminal on the harness side of the connector. If no reference signal is present, connect the meter set to ohms (with the ignition off) between the reference voltage pin on the TFL and the reference voltage pin on the PCM. If the meter reads “out of limits” (OL), there is an open circuit between the PCM and sensor that needs to be located and repaired. If the meter reads a numeric value, there is continuity in the circuit.
If everything is functioning properly up to this point, check that there is power coming out of the PCM. To do this, turn the ignition on and set the meter to DC volts. Connect the positive meter lead to the reference voltage terminal on the PCM and the negative lead to ground. If there is no reference voltage from the PCM, the PCM is likely faulty. However, PCM failures are rare, so it is advisable to double-check the previous steps.
Check The Ground Side Of The Circuit
With the ignition off, use a digital multimeter set to ohms to check for continuity. Connect the meter between the transmission fluid level sensor ground terminal and chassis ground. If the meter reads a numeric value, there is continuity in the circuit. If the meter reads “out of limits” (OL), there is an open circuit between the PCM and sensor that needs to be located and repaired.
Check The Sensor
If everything checks out up to this point, it is likely that the sensor itself is faulty. To check this, turn the ignition off and set your multimeter to read ohms. Remove the transmission fluid level sensor connector and connect the meter to the sensor terminals. If the meter reads “out of limits” (OL), the sensor is internally open and should be replaced.
