P070C A low transmission fluid level sensor circuit

P070C A low transmission fluid level sensor circuit

OBD-II DTC Datasheet

Low signal level in the transmission fluid level sensor circuit

What does this mean?

This Generic Transmission Diagnostic Trouble Code (DTC) usually applies to OBD-II equipped vehicles that have a transmission fluid level sensor. Vehicle brands may include, but are not limited to, GM, Chevrolet, Ford, Dodge, Ram, Toyota, Hyundai, etc. This code is not universally accepted.

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

When the liquid level is within the acceptable range, the switch is grounded. When the transmission fluid falls below a predetermined level, the switch opens and the instrument panel displays a low transmission fluid level warning.

TFL sensors receive a voltage reference from the PCM. The PCM monitors the circuit and, when it detects that the switch is open, triggers a low fluid level warning in the instrument cluster.

The P070C code is set when the PCM detects a low transmission fluid level sensor signal. This usually indicates a short circuit in the circuit. Associated codes include P070A, P070B, P070D, P070E, and P070F.

Code severity and 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, which, if left unattended, can damage the transmission. It is recommended to fix this code as soon as possible.

Symptoms of a P070C trouble code may include:

• Illuminated transmission fluid low warning light
• Check Engine Light
• Drivetrain performance issues

Common Causes of This DTC

Possible reasons for this code could include:

• Defective transmission fluid level sensor
• Low transmission fluid level
• Wiring problems
• Defective PCM

Diagnostic and repair procedures

Start by checking the level and condition of the transmission fluid according to the manufacturer's recommendations. Then inspect the transmission fluid level sensor and associated wiring. Look for loose connections, damaged wiring, etc. If damage is found, repair as needed, clear the code and see if it returns. Then check the technical service bulletins (TSBs) for the problem. If nothing is found, you will need to proceed to the step-by-step system diagnostics.

The following is a generalized procedure as the testing of this code differs from vehicle to vehicle. To accurately test the system, you need to refer to the manufacturer's diagnostic flowchart.

Check the wiring

Before proceeding, you need to consult the factory wiring diagrams to determine which wires are which. Autozone offers free online repair guides for many vehicles and ALLDATA offers a one-car subscription.

Check the reference voltage side of the circuit.

Ignition ON, use a DC voltage setting DMM to check the reference voltage (usually 5 or 12 volts) from the PCM. To do this, connect the Meter negative lead to ground and the Meter positive lead to the B + sensor terminal on the harness side of the connector. If there is no reference signal, connect a meter set to ohms (ignition off) between the TFL reference terminal and the PCM reference terminal. If the meter reading is out of tolerance (OL), there is an open circuit between the PCM and the sensor that needs to be located and repaired. If the counter reads a numeric value, there is continuity.

If everything is fine up to this point, you will want to check if power is coming out of the PCM. To do this, turn on the ignition and set the meter to constant voltage. Connect the meter positive lead to the PCM reference voltage terminal and the negative lead to ground. If there is no reference voltage from the PCM, the PCM is probably faulty. However, PCMs rarely fail, so it's a good idea to double check your work up to that point.

Check circuit ground

Ignition OFF, use a resistor DMM to check the continuity. Connect a meter between the transmission fluid level sensor ground terminal and chassis ground. If the counter reads a numeric value, there is continuity. If the meter reading is out of tolerance (OL), there is an open circuit between the PCM and the sensor that needs to be located and repaired.

Check the sensor

If everything goes well by this point, the sensor is probably faulty. To test this, turn off the ignition and set the multimeter to read in ohms. Remove the transmission fluid level sensor connector and connect the meter to the sensor terminals. If the meter reading is out of tolerance (OL), the sensor is open from the inside and must be replaced.

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