Fault code P06B8 is called “Internal Control Module Non-Volatile Random Access Memory (NVRAM) Error” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P06B8
A stored code P06B8 means that the control module (PCM) has detected an internal processor performance error with non-volatile access memory. Other controllers may also detect an internal PCM performance error (with NVRAM) and cause this fault to be stored.
The internal control module monitoring processors are responsible for various self-diagnostic functions of the controller. They are also responsible for the overall check of the internal control module operation.
NVRAM input and output signals are self-tested and constantly monitored by the PCM as well as other controllers. The Transmission Control Module (TCM), Traction Control Module (TCSM), and other controllers also communicate with NVRAM.
When the ignition is turned on and voltage is applied to the PCM, the NVRAM self-test is initiated. In addition to performing internal controller self-tests, the controller network (CAN) also compares signals from each individual module.
This is done to ensure that each controller is functioning properly. All of these tests are performed simultaneously.
If the PCM detects an internal mismatch in the NVRAM processor memory, code P06B8 will be stored and the malfunction indicator lamp (MIL) may illuminate. It may take several fault cycles for the MIL to illuminate, depending on the perceived severity of the fault.
Symptoms of vehicle malfunctions
The main signal that an error P06B8 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- The “Check engine” control lamp on the control panel will light up (the code will be stored as a fault).
- Other related fault codes may also be present.
- Various symptoms related to engine operability.
The internal control unit processor codes are categorized as serious. A stored code P06B8 can lead to various driving problems with the vehicle.
Factors that can cause this error code
The error code P06B8 can mean that one or more of the following problems have occurred:
- Open or short in the CAN bus circuit or connectors.
- Poor grounding of the control unit.
- Sometimes a faulty PCM module is the cause.
How to fix or reset OBD-2 code P06B8
Some suggested steps for troubleshooting and fix the error code P06B8:
- Read all stored data and error codes with an OBD-II scan tool.
- Clear the error codes from the computer memory.
- Test-drive the vehicle to find out if fault P06B8 appears again.
- Visually inspect the CAN bus wires and connectors.
- Check the grounding of the control module.
- If the error persists, check the PCM module.
Diagnose and repair of problems
If ECM/PCM power codes are present, they must be cleared before attempting to diagnose fault P06B8.
Next, connect the scan tool to the vehicle’s diagnostic port and retrieve any stored codes and data. Make a note of this information in case the code turns out to be intermittent.
After recording all the necessary information, clear the codes and test drive the vehicle until the code is cleared or the PCM goes into standby mode. If the PCM goes into standby mode, the code is intermittent and will be more difficult to diagnose.
Check the controller and electrical parts
Use a multimeter to check the fuses and power relays on the controller. Check and replace blown fuses if necessary. Fuses should be checked with the circuit loaded.
If all fuses and relays are working as they should, a visual inspection of the controller wiring and harnesses should be performed. Chassis and motor grounding should also be checked.
Visually inspect the system controllers for signs of water, temperature, or collision damage. Any controller that is damaged, especially by water, should be considered faulty.
If the power and ground circuits of the controller are intact, it is likely that the controller itself is defective or that a programming error exists. Reprogramming the control module will be necessary to replace it.
Unlike most other codes, fault P06B8 is most likely caused by a faulty controller or its programming error.
Some aftermarket PCM manufacturers offer preprogrammed controllers for certain models. Contact your auto parts supplier with the vehicle serial number, mileage, and other pertinent information.
On which vehicles does this problem occur most frequently
Fault code P06B8 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Ford (Escape, Explorer, F-150, Focus, Fusion)
- Mazda (3)
- Peugeot
Fault code P06B8 can sometimes be found with other errors. The most common are the following: P06B6, P06B7, P2832.
