Fault code P064D – internal control module O2 sensor processor performance (Bank 1)

Fault code P064D is called “Internal Control Module O2 Sensor Processor Performance (Bank 1)” 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 P064D

This Diagnostic Trouble Code (DTC) is a generic code. Error P064D is considered a generic code because it applies to all makes and models of vehicles. Although the specific repair steps may vary slightly depending on the model.

When OBD-II code P064D is saved, the transmission control module (PCM) detects an internal processor performance error with oxygen sensor circuit O₂. Bank 1 identifies the engine group that contains cylinder 1.

The oxygen sensors are designed with a zirconium dioxide sensing element. Which is protected by a specially designed vented steel housing. An electrical signal is sent to the PCM according to the percentage of oxygen particles in the engine exhaust gases. It is compared with the oxygen content of the ambient air.

Deviations between the concentration of oxygen molecules in the ambient air and the concentration of oxygen ions in the exhaust gases cause That the heated oxygen ions inside the O2 sensor move very quickly between the platinum layers.

These voltage changes are identified by the PCM as changes in the oxygen concentration in the exhaust gas. Which indicate that the engine is running on a lean or rich mixture.

Each time the ignition is turned on and voltage is applied to the PCM, a self-test of the HO₂S sensor is initiated. In addition to performing the self-test of the internal module. The Controller Area Network (CAN) also compares the signals from each individual module to ensure that each controller is operating properly.

If the PCM detects an internal mismatch in the HO₂S sensor functionality, code P064D will be stored and the malfunction indicator lamp (MIL) may illuminate. In addition, if the PCM detects a problem between any of the on-board controllers. Which indicates an internal HO2S sensor error, code P064D will also be stored.

It may take several failure cycles for the MIL check lamp to turn on, depending on the perceived severity of the fault.

Symptoms of vehicle malfunctions

The main signal that an error P064D has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.

It can also be warning signs such as:

1. The “Check engine” control lamp on the control panel will light up (the code will be stored as a fault).
2. Other related fault codes may also be present.
3. Various symptoms related to engine responsiveness.
4. Reduced engine power output.
5. Increased fuel consumption.

Codes related to internal module processor control should be categorized as serious. Stored code P064D can lead to various drivability problems as well as reduced fuel efficiency.

Factors that can cause this error code

The error code P064D can mean that one or more of the following problems have occurred:

• The oxygen sensor O₂ may be defective.
• There may be damage in the electrical circuit of the oxygen sensor O₂.
• High resistance or break in the oxygen sensor signal circuit O₂.
• Clogged catalytic converter.
• Engine exhaust leakage.
• Defective controller power relay or blown fuse.
• Improper grounding of control module.
• Faulty controller or programming error.

How to fix or reset OBD-2 code P064D

Some suggested steps for troubleshooting and fix the error code P064D:

1. Read all stored data and error codes with an OBD-II scan tool.
2. Clear the trouble codes from the computer memory and test-drive the vehicle to find out if error P064D appears again.
3. Observe the oxygen sensor data in real time using the scan tool. To find out if the voltage drops below 0.2 volts when the vehicle slows down.
4. Check the oxygen sensor for contamination due to coolant or engine oil leakage. Replace the oxygen sensor O₂ if necessary.
5. Inspect the electrical wires related to the oxygen sensor for moisture or mechanical damage. Repair any faults found.

Diagnose and repair of problems

Check that the oil level is at the proper level, that it is not diluted with fuel or coolant, and that it is not of a thick, tarry consistency. If necessary, refill or replace the oil before proceeding with further diagnosis.

Perform a thorough visual inspection of the wiring to look for damaged, burned, disconnected, shorted, or corroded wires and connectors. If necessary, repair, clear code P064D and re-scan the system to see if the code returns.

Check the wiring with a multimeter

Make sure that all other codes are diagnosed and repaired before dealing with the error. Prepare some tools such as a diagnostic scanner, digital voltmeter. As well as a source of information about the vehicle.

Visually inspect the system’s wiring harnesses and connectors. Pay particular attention to the harnesses near the hot exhaust pipes and manifolds. Also, those routed near sharp edges of parts.

Then connect the scan tool to the vehicle’s diagnostic port and read any stored trouble codes. This information can be useful if the error turns out to be floating, so write it down for later. Now clear the codes and see if code P064D has been reset.

Check the sensor

After that, start the engine, wait for normal operating temperature and let it idle. If the engine is running efficiently, the O₂ sensor data should fluctuate regularly between 1 and 9 millivolts. If the voltage fluctuation is slower than expected, P064D will be stored.

Connect the voltmeter test leads to the sensor ground and signal leads to monitor the data from the O₂ sensor in real time. Check the resistance as well as the voltage and ground signals.

To prevent damage to the control module, disconnect the appropriate controllers before testing the system circuit resistance with a voltmeter.

Controller diagnostics

Check all fuses and relays associated with the controller to ensure they are working properly. Check chassis and motor grounding, use a multimeter to check for continuity.

Visually inspect the system controllers for signs of water, heat, or collision damage. Any controller that is damaged, especially by water, is considered faulty.

If the power and ground circuits of the controller are intact, a faulty controller or programming error may be the cause. Replacing the controller will correct error P064D, but will most likely require reprogramming it beforehand.

On which vehicles does this problem occur most frequently

Fault code P064D can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:

• Dodge (RAM)
• Ford
• Land Rover
• Mazda (CX-7)
• Mercedes-Benz
• Opel
• Smart

Fault code P064D can sometimes be found with other errors. The most common are the following: P064E, P2297, P2298.

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