What Does It Mean?
This is a generic diagnostic trouble code (DTC) for the powertrain and generally applies to OBD-II vehicles. This may include, but is not limited to, vehicles from Ford, GMC, Chevy, Mercedes Benz, Buick, Land Rover, Mazda, Nissan, Citroen, Maserati, etc. Although generic, the exact repair steps may vary depending on the year, make, model, and powertrain configuration.
When a P062B code is stored, it means that the Powertrain Control Module (PCM) has detected an internal performance error with the fuel injection control system. Other controllers may also detect an internal PCM performance error (in the fuel injection control system) and result in the storage of a P062B.
The internal control module monitoring processors are responsible for various controller self-test tasks and the overall responsibility of the internal control module. The input and output signals of the fuel injection control system are subjected to self-test and are continuously monitored by the PCM and other associated controllers. The Transmission Control Module (TCM), Traction Control System Module (TCSM), and other controllers are subject to interaction with the fuel injection control system.
Typically, the fuel injector controller is integrated into the PCM. At least one fuel injector per cylinder is used to deliver a precise amount of fuel to the cylinder at the exact moment it is needed to maximize performance and efficiency.
You might think of each fuel injector as a type of solenoid opened or closed using battery voltage. When the ignition is turned on, a constant battery voltage is supplied to each fuel injector. To complete the circuit and cause each fuel injector to spray a precise amount of fuel at the appropriate time, the PCM provides a momentary ground pulse.
The PCM uses input signals from the Crankshaft Position Sensor (CKP), Camshaft Position Sensor (CMP), oxygen sensors, Mass Air Flow Sensor (MAF), and Throttle Position Sensor (TPS) to monitor the performance of the fuel injector controller.
Whenever the ignition is turned on and the PCM is powered up, self-tests of the fuel injection control system are initiated. In addition to performing internal controller self-tests, the Controller Area Network (CAN) also compares the signals from each individual module to ensure that each controller is functioning correctly. These tests are performed simultaneously.
If the PCM detects anomalies in the internal fuel injector control system, a P062B code will be stored, and a Malfunction Indicator Lamp (MIL) may be illuminated. Furthermore, if the PCM detects a discrepancy between any of the onboard controllers, which would indicate an internal fuel injector controller error, a P062B code will be stored, and a Malfunction Indicator Lamp (MIL) may be illuminated. Multiple failure cycles may be required for the MIL to illuminate, depending on the perceived severity of the malfunction.
Photo of a PCM with the cover removed:
Powertrain Control Module PCM
How Severe Is This DTC?
Internal control module processor codes should be classified as severe. A stored P062B code could lead to serious driving problems, suddenly and without warning.
What Are Some of the Symptoms of the Code?
Symptoms of a P062B trouble code may include:
- Engine misfires
- Excessively lean or rich exhaust
- Hesitation during acceleration
- Stored misfire codes
What Are Some of the Common Causes of the Code?
Causes of this P062B trouble code may include:
- Open or shorted circuits or connectors in the CAN bus
- Insufficient control module ground
- Faulty fuel injector(s)
- Faulty controller or programming error
- Open or shorted circuits between the fuel injector and the PCM
What Are the Troubleshooting Steps for P062B?
Even for the most experienced and well-equipped professional technician, diagnosing a P062B code can be very challenging. There is also the issue of reprogramming. Without the necessary reprogramming equipment, it will be impossible to replace a faulty controller and perform a successful repair.
If ECM/PCM power codes are present, they will obviously need to be addressed before attempting to diagnose a P062B. Additionally, if there are individual fuel injector codes or fuel injector circuit codes, these should be diagnosed and repaired first.
Several preliminary tests can be performed before declaring an individual controller faulty. A diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable vehicle information source will be necessary. A fuel injector noid light will also prove useful when testing fuel injector circuits.
Connect the scanner to the vehicle’s diagnostic port and retrieve all stored codes and freeze frame data. You will want to note this information, just in case the code turns out to be intermittent. After recording all relevant information, clear the codes and test-drive the vehicle 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 P062B to be stored may even need to worsen before a diagnosis can be made. If the code resets, continue with this short list of preliminary tests.
When trying to diagnose a P062B, information can be your best tool. Check your vehicle information source for Technical Service Bulletins (TSBs) that correlate the stored code, the vehicle (year, make, model, and engine), and the symptoms presented. If you find the right TSB, it may provide diagnostic information that will assist you significantly.
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.
Use the noid light to test individual fuel injector circuits and perform necessary repairs. Use the DVOM to test fuel injectors following the manufacturer’s specifications and procedures. If all fuel injectors and fuel injector circuits appear to be functioning as expected, proceed to test the controller’s power and ground.
Use the DVOM to test the controller’s power fuses and relays. Test and replace blown fuses as needed. Fuses should be tested under load.
If all fuses and relays appear to be functioning as expected, a visual 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. Use the DVOM to test ground integrity.
Visually 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. In some cases, you can purchase pre-programmed controllers from aftermarket sources. Other vehicles/controllers will require onboard reprogramming that can only be performed by a dealership or another qualified source.
Unlike most other codes, P062B is likely caused by a faulty controller or a controller programming error
Test the system ground integrity by connecting the DVOM’s negative test lead to ground and the positive test lead to battery voltage