Trouble code solution P0625: decoding, causes, resetting, meaning

Contents

Technical description and explained code P0625
Symptoms of vehicle malfunctions
Factors that can cause this error code
How to fix or reset OBD-2 code P0625
Diagnose and repair of problems
Checking the wiring
Testing the alternator
On which vehicles does this problem occur most frequently
Video

Fault code P0625 is called “Generator Field “F” Terminal Circuit Low” 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 P0625

The OBD-II fault code P0625 is a generic fault code defined as “low signal level in the alternator field control terminal “F” circuit”. The letter “F” indicates that a low signal level has been detected in the field coil control circuit.

The alternator is designed to generate the current needed by the vehicle at a given time. This is accomplished by a circuit in the control module that estimates the total power consumption.

The excitation coil can be recognized by the winding, which is visible through the vents on most alternators. It surrounds the alternator armature and remains stationary in the housing.

The PCM normally monitors the continuity of the alternator field control circuit at all times when the engine is running. The alternator field coil is an integral part of running the alternator and maintaining the battery charge level.

Each time the ignition is turned on and power is applied to the PCM, several self-tests of the controller are performed. In addition to performing internal controller self-tests, the Controller Area Network (CAN) is used to compare signals from each individual module. To make sure that the different systems communicate properly.

If a low signal level is detected when monitoring the generator field control circuit, code P0625 will be stored and the malfunction indicator lamp (MIL) may illuminate. Depending on the perceived severity of the fault, it may take several failure cycles for the MIL to illuminate.

Symptoms of vehicle malfunctions

The main signal that an error P0625 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 memorized as a fault).
Other related fault codes may also be present.
Some gauges or sensors on the dashboard may be inactive.
The engine stalls or starts poorly.
Unintentional engine shutdown.
Reduced engine power.

Stored fault code P0625 can lead to a variety of drivability problems, including no starting or low battery. Therefore, internal control module errors should always be taken seriously.

Factors that can cause this error code

The error code P0625 can mean that one or more of the following problems have occurred:

Faulty alternator.
Faulty alternator control module.
Open or short circuit in wiring harness.
Faulty alternator warning lamp.
Loose or damaged connectors.
Poor grounding is a common cause.
Low charge level or fully discharged battery.
Voltage surges caused by improper starting procedures from an external source.
Sometimes the cause is a faulty PCM module or programming error.

How to fix or reset OBD-2 code P0625

Some suggested steps for troubleshooting and fix the error code P0625:

Read all stored data and error codes with an OBD-II scan tool. To find out when and under what circumstances error P0625 appeared.
Clear the error codes from the computer memory and test drive the vehicle to see if the fault reappears.
If the error code appears again, visually inspect the electrical wires and control module connector.
Take out and check the alternator warning light.
Visually inspect and test the alternator.
If necessary, repair or replace the alternator and any defective wires.
Check the voltage regulator and battery pack.
If there are no defects, check the PCM itself and its software part.

Diagnose and repair of problems

When a fault code P0625 occurs, other errors may sometimes be present as well. Associated codes usually refer to abnormal system voltages (high or low). And also to codes of performance range mismatch, which may refer to different sensors.

If there are no additional codes, the first thing to do is to check the battery to determine its state of charge and overall performance. If the battery is discharged or damaged, recharge or replace it.

Checking the wiring

After checking the battery, visually inspect all wiring associated with the alternator. If necessary, repair or replace to ensure effective load transfer.

If no visible signs of shorts or other damage are found, use a voltmeter to check the resistance and ground. Replace if necessary to ensure that all electrical values are within the limits specified by the manufacturer.

Also locate any fuses that are in any way connected to the charging system. After checking, replace any damaged or suspect fuses.

Testing the alternator

If all the wiring is checked, you need to test the alternator itself with a multimeter. In most cases, a faulty alternator is the cause of error P0625.

If the defect in the alternator is confirmed, replace it with a new or remanufactured alternator, as this is almost always more cost-effective than repairing it. However, make sure that the unit being replaced is identical to the original in all respects, including mounting brackets and specifications.

After replacement, start the engine and watch the indicator light on the dashboard to make sure the alternator is working properly. The warning light should go out within a few seconds.

If the charging lamp does not come on, it may be the cause of the error. Therefore, you need to test and troubleshoot the alternator check lamp.

You can also measure the system voltage, it should be between 14.2 and 14.8 volts. Allow the vehicle to run at least one full drive cycle before rescanning the system. Most likely there will be no P0625 error, but sometimes additional clearing with the scan tool is necessary.