P070B Transmission Fluid Level Sensor Circuit Range/Performance

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P070B Transmission Fluid Level Sensor Circuit Range/Performance

OBD-II Trouble Code Technical Description

Transmission Fluid Level Sensor Circuit Range/Performance

What does that mean?

This generic powertrain diagnostic trouble code (DTC) typically applies to OBD-II equipped vehicles that have a transmission fluid level sensor. Makes of vehicles may include but are not limited to GM, Chevrolet, Ford, Dodge, Ram, Toyota, Hyundai, etc. This code is uncommon.

The transmission fluid level (TFL) sensor is used to illuminate a warning light on the dash in the case of low fluid level.

When the fluid level is within an acceptable range, the switch is grounded. When the transmission fluid drops below a predetermined level, the switch opens and a "low transmission fluid level" warning is displayed on the dash.

TFL sensors receive a reference voltage from the PCM. The PCM monitors the circuit and when it recognizes the switch has opened, it turns on the low fluid warning on the instrument cluster.

Code P070B is set when the PCM detects a malfunction in the range or performance of the transmission fluid level sensor. Related codes include P070A, P070C, P070D, P070E, and P070F.

Code Severity & Symptoms

The severity of this transmission code is moderate to severe. In some cases, this and related codes can indicate a low transmission fluid level, that when left unattended to, can result in transmission damage. It’s a good idea to address this code as soon as possible.

Symptoms of a P070B trouble code may include:

  • Illuminated low transmission fluid warning light
  • Illuminated check engine light
  • Transmission performance problems
  • Common Causes Of This DTC Code

    Possible causes for this code may include:

  • Faulty transmission fluid level sensor
  • Low transmission fluid level
  • Wiring problems
  • Faulty PCM
  • Diagnostic and Repair Procedures

    Begin by checking the transmission fluid level and condition in accordance with the manufacturer recommendations. Next, inspect the transmission fluid level sensor and the corresponding wiring. Look for loose connections, damaged wiring, etc. If damage is found, repair as necessary, clear the code and see if it returns. Next, check for technical service bulletins (TSBs) regarding the issue. If nothing is found, you will need to move forward to step by step diagnosis of the system.

    The following is a generalized procedure, as testing for this code varies between vehicles. To accurately test the system, you’ll want to refer to the manufacture’s diagnostic flow chart.

    Check The Wiring

    Before proceeding, you’ll want to consult the factory wiring diagrams to determine which wires are which. 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 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 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 will need to be located and repaired. If the meter reads a numeric value, there is continuity.

    If everything is good up to this point, you’ll want to 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 not a reference voltage from the PCM, the PCM is probably faulty. However, PCMs rarely go bad, so it’s a good idea to double check your work up to this point.

    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. If the meter reads out of limits (OL) there is an open circuit between the PCM and sensor that will need to be located and repaired.

    Check The Sensor

    If everything checks out to this point, the sensor is probably 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 open internally and should be replaced.

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    "Delete Error Code Permanently, Disable DTC Error Code Function for p070b in the ECU"

    In extreme cases, we even have the option to permanently remove the specific DTC p070b and disable the function of the specific error code in the ECU. All other fault code functions will then continue to work to protect the engine. This is different from clearing an error code with a diagnostic device. We have the option to permanently remove the function of the specific error code, so that it never comes back. Also emergency running that occurs on the specific error code can be solved in most cases.

    Of course we prefer to first try to solve the cause of the error code, but sometimes the only solution is to permanently disable the DTC function of p070b.

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