What does it mean?
This is a generic diagnostic trouble code (DTC) and applies to many OBD-II vehicles (1996-newer). This may include, but is not limited to, vehicles from Chrysler, Ford, General Motors, Mercedes-Benz, Toyota, etc. Although generic, the exact repair steps may vary depending on the year, make, model, and powertrain configuration.
A stored P064B code means that the Powertrain Control Module (PCM) has detected a malfunction in the Power Take-Off (PTO) control module.
The PTO control module is responsible for initiating various PTO functions. These may include activating specified lighting, increasing engine speed (when the PTO is engaged), as well as disengaging the drive wheels (using the transfer case). In most cases, the PTO controller is integrated into the PCM, but it can also be a standalone module.
The power take-off is a function included on many hydraulically-operated service vehicles such as tow trucks and dump trucks. It allows a large hydraulic pump to be driven using engine power. With the vehicle stationary and the engine idling, a transfer case on the transmission output shaft allows the drive wheels to be disengaged and the pump to be engaged via an auxiliary drive shaft. This system is quite durable and provides abundant power for heavy functions such as lifting another vehicle (wrecker) or dumping heavy materials (dump truck). There are many specialized applications that use a power take-off system in addition to tow trucks and dump trucks.
Whenever the ignition is turned on and the PCM is powered, several controller self-tests are performed. By performing controller self-tests, the PCM can monitor serial data transmitted on the Controller Area Network (CAN) to ensure that the onboard controllers interface correctly.
If a problem is detected while monitoring the PTO control module, a P064B code will be stored and a Malfunction Indicator Lamp (MIL) may illuminate.
Code P064B
How severe is this DTC?
For safety reasons, power take-off control module codes should be taken seriously. A stored P064B code can result in a lack of PTO function and may pose serious safety risks.
What are some of the symptoms of the code?
Symptoms of a P064B trouble code may include:
- Inoperative power take-off
- Slow and labored engine cranking
- Engine locking up during starting
- Engine driveability issues
- Other stored codes
What are some common causes of the code?
Causes of this code may include:
- Faulty power take-off controller or PCM
- Open module control voltage supply circuit
- PCM programming error
- Open or shorted control circuit
What are the troubleshooting steps for P064B?
A diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information will be needed to diagnose a P064B code.
Consult your vehicle information source for Technical Service Bulletins (TSBs) that match the stored code, the vehicle (year, make, model, and engine), and the symptoms presented. If you find the relevant TSB, it may provide helpful diagnostic information.
Start by connecting the scanner to the vehicle’s diagnostic port and retrieving all stored codes and freeze frame data. You will want to note this information, in case the code proves to be intermittent. After recording all relevant information, clear the codes and test the vehicle (if possible) until the code resets or the PCM enters readiness mode.
If the PCM enters readiness mode, the code is intermittent and will be more difficult to diagnose. The condition that caused the P064B to be stored may need to worsen before an accurate diagnosis can be made. If the code resets, continue your diagnosis.
Use your vehicle information source to obtain connector face views, connector pinout diagrams, component locators, wiring schematics, and diagnostic flowcharts related to the code and the specific vehicle.
Check for battery voltage on the PTO control circuit using the appropriate wiring schematic and your DVOM. If not, check the system fuses and relays and replace faulty parts as needed.
If there is no voltage (and/or ground) on the PTO control circuit (and all fuses and relays appear to be functioning correctly), an inspection of the wiring and harnesses related to the controller is necessary. You will also want to check the chassis and engine ground junctions. Use your vehicle information source to obtain ground locations for the related circuits.
If there is voltage (and ground) on the PTO control circuit, inspect the system controllers for signs of water, heat, or collision damage. Any damaged controller (especially by water) should be considered faulty.
If the controller’s power and ground circuits are intact, suspect a faulty controller or a controller programming error. Replacing the controller will require reprogramming.
Test the integrity of the controller ground by connecting the DVOM’s negative test lead to ground and the positive lead to battery voltage.