What Does It Mean?
Diagnostic Trouble Code (DTC)
This diagnostic trouble code (DTC) is a generic powertrain code, meaning it applies to OBD-II equipped vehicles. This may include, but is not limited to, vehicles from Ford, Chevrolet, Honda, etc. Although generic, specific repair steps may vary by make/model.
Meaning of Code P06A7
If your OBD-II vehicle has a stored P06A7 code, it means the Powertrain Control Module (PCM) has detected an out-of-range reference voltage signal or a performance issue with a specific sensor designated as “B”. The sensor in question is typically associated with the automatic transmission, transfer case, or one of the differentials.
A more specific sensor code will almost always accompany this code. P06A7 adds that the sensor’s reference circuit voltage is out of range or not performing as expected.
To determine the location and function of the “B” sensor for the vehicle in question, consult a reliable vehicle information source (e.g., AllDataDIY). Consider a PCM programming error if P06A7 is stored alone. You’ll need to diagnose and repair any other sensor codes before addressing P06A7 – but keep in mind the reference voltage range/performance condition.
Operation of Sensor “B”
The sensor in question is supplied with reference voltage (typically 5 volts) through a switched circuit (powered with the ignition on). There will also be a ground signal.
The sensor will be of variable resistance or electromagnetic type and will complete the circuit. The sensor’s resistance should decrease as pressure, temperature, or speed increases and vice versa. When the sensor’s resistance changes (under varying conditions), it provides the PCM with an input voltage signal.
Symptoms of Code P06A7
The severity of this DTC depends on which sensor circuit is experiencing the abnormal voltage situation. Other stored codes must be considered before determining severity.
Possible Symptoms:
- Transmission fails to switch between sport and economy modes
- Transmission shifting malfunctions
- Delayed (or no) transmission engagement
- Transmission fails to switch between four-wheel drive and two-wheel drive modes
- Transfer case fails to shift from low to high range
- No front differential engagement
- No front hub engagement
- Erratic or inoperative speedometer/odometer
Possible Causes
Factors That Can Trigger Code P06A7
- Faulty sensor
- Defective or blown fuses and/or fuse links
- Faulty system power relay
- Open circuits and/or connectors
Diagnostic and Repair Procedures
Required Tools
A diagnostic scanner, digital volt/ohmmeter (DVOM), and reliable vehicle information source (such as AllDataDIY) will be needed to diagnose a stored P06A7 code. A portable oscilloscope may also prove useful in your diagnosis.
Diagnostic Steps
- Consult Information Sources: Determine the location and function of the sensor in question for your vehicle.
- Visual Inspection: Examine wiring harnesses and connectors related to the sensor system. Replace damaged components.
- Retrieving Error Codes: Connect an OBD-II scanner to the vehicle’s diagnostic port.
- Clearing Codes: Clear stored codes and test drive the vehicle.
- Checking Voltages: Use the DVOM to test reference voltage and ground signals.
- Sensor Testing: If voltage and ground signals are present, test sensor resistance and continuity.
- Circuit Check: If reference voltage is low, test circuit resistance and continuity between sensor and PCM.
Additional Diagnostic Notes
- This type of code is typically provided as support for a more specific code.
- A stored P06A7 code is normally associated with the transmission.
By following these steps, you’ll be able to effectively diagnose and repair a stored P06A7 code on your vehicle.