Technical Description of OBD-II Trouble Code
The circuit for Sensor Reference Voltage “D” is open.
What does that mean?
This diagnostic trouble code (DTC) is a generic powertrain code that applies to vehicles equipped with OBD-II. While it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
When a stored P06A3 code is found, it indicates that the powertrain control module (PCM) has detected an open circuit for a specific sensor, designated as “D” in this case. In the context of OBD-II codes, “open” can be used interchangeably with “absent”.
The sensor in question is typically associated with the automatic transmission, transfer case, or one of the differentials. This code is usually accompanied by a more specific sensor code. The P06A3 code indicates that the circuit is open. To determine the location and function of the sensor specific to your vehicle, consult a reliable vehicle information source such as All Data DIY. If the P06A3 code is stored alone, it is possible that a PCM programming error has occurred. However, it is important to diagnose and repair any other sensor codes before addressing the P06A3 code, while keeping the open “D” circuit in mind.
A reference voltage, typically five volts, is applied to the sensor via a switched circuit that is energized with the key on. There should also be a ground signal. The sensor is likely of the variable resistance or electromagnetic type and completes a specific circuit. As pressure, temperature, or speed changes, the sensor resistance decreases or increases, providing the PCM with an input voltage signal. If the PCM does not receive this input voltage signal, the circuit is considered open and a P06A3 code is stored.
A malfunction indicator lamp (MIL) may also illuminate, but it is important to note that some vehicles require multiple drive cycles with a failure for the MIL to illuminate. Therefore, it is advisable to allow the PCM to enter readiness mode before considering a repair successful. After performing the necessary repairs, clear the code and drive the vehicle normally. If the PCM enters readiness mode, the repair was successful. If the code is reset, the PCM will not enter readiness mode, indicating that a problem still exists.
Severity & Symptoms
The severity of a stored P06A3 code depends on which sensor circuit is experiencing an open condition. It is necessary to consider other stored codes before determining the severity.
Symptoms of a P06A3 code may include:
Causes
Possible causes for this engine code include:
Diagnostic and Repair Procedures
To diagnose a stored code P06A3, you will need access to a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable vehicle information source such as All Data DIY. A portable oscilloscope may also be helpful in certain situations.
Use your vehicle information source to determine the location and function of the sensor specific to your vehicle. Check system fuses and fusible links with the circuit under a full load, as fuses that appear normal under low load conditions may fail when the circuit is fully loaded. Replace blown fuses, keeping in mind that a shorted circuit is likely the cause of the blown fuse.
Perform a visual inspection of the wiring harnesses and connectors related to the sensor system. Repair or replace any damaged or burned wiring, connectors, and components as necessary.
Next, connect the scanner to the vehicle diagnostic connector and retrieve all stored trouble codes. Write them down, along with any related freeze frame data, as this information may be helpful if the code is intermittent. Clear the code and test drive the vehicle to see if it is immediately reset.
If all system fuses are intact and the code is immediately reset, use the DVOM to test the reference voltage and ground signals at the sensor. Typically, you should expect to find five volts and a common ground at the sensor connector.
If the voltage and ground signals are present at the sensor connector, continue by testing the sensor resistance and continuity levels. Refer to your vehicle information source for testing specifications and compare your actual findings to them. Sensors that do not comply with these specifications should be replaced.
Before testing resistance with the DVOM, disconnect all related controllers from the system circuits. If there is no reference voltage signal at the sensor, disconnect all related controllers and use the DVOM to check circuit resistance and continuity between the sensor and the PCM. Replace any open or shorted circuits as necessary. If an electromagnetic sensor is used with a reciprocating signal, use the oscilloscope to monitor live data, paying particular attention to glitches and completely open circuits.
Additional diagnostic notes:
