Fault code P0612 is called “Fuel Injector Control Module Relay Circuit Malfunction” 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 P0612
OBD-II fault code P0612 is a generic fault code, which is defined as a “fault in the fuel injector control module relay circuit”. The fault is related to the part of the control module (PCM) that controls the operation of the fuel injectors.
In some cases, the fuel injector controller may be a separate control unit. But more often it is integrated into the PCM, which saves space, time and money for automakers.
When the ignition is turned on and voltage is applied to the PCM, several self-tests of the controller are performed. In addition to performing internal controller self-tests, a controller network (CAN) is tested. Which is used to compare signals from each individual module to make sure that the different controllers are communicating properly.
If the PCM detects that the fuel injector relay control cannot be controlled effectively, code P062F will be stored. Also, if the PCM detects a mismatch between any of the onboard controllers. Which indicates an internal fuel injector relay control error, this code 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 P0612 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.
- The engine does not accelerate well.
- Floating revolutions, as well as attempts to stall at idle.
- Decreased power output of the engine.
- Increased fuel consumption.
Trouble related to an internal module should be categorized as a serious code. A stored error P0612 can suddenly and without warning lead to serious driving problems.
Factors that can cause this error code
The error code P0612 can mean that one or more of the following problems have occurred:
- Controller power relay is defective or fuse is blown.
- Faulty fuel injector control module.
- Damage by water or overheating.
- Open or short circuit in wiring harness.
- Corroded electrical connector.
- CAN bus may be faulty and shorted to ground or wire breakage.
- Insufficient grounding of the control module.
- Sometimes the cause is the PCM itself.
How to fix or reset OBD-2 code P0612
Some suggested steps for troubleshooting and fix the error code P0612:
- Read all stored data and error codes with an OBD-II scan tool. To find out when and under what circumstances error P0612 appeared.
- Clear the error codes from the computer memory and test-drive the vehicle to find out if the fault appears again.
- Check the relay and fuel injector control module.
- If the error code appears again, visually inspect the control module (PCM) electrical wiring and connector.
- Measure battery voltage and compare it to the value specified in the manufacturer’s specifications.
- Check the continuity of the PCM power and ground circuits with a multimeter.
- Evaluate the Control Module (PCM) operation following the vehicle manufacturer’s procedure.
- Clear the error code from the computer memory again, and test drive the vehicle to determine if the problem has been resolved.
Diagnose and repair of problems
If ECM/PCM power codes are present, they must be cleared before attempting to diagnose error P0612.
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, error P0612 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 P0612 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Chevrolet
- Dodge (RAM)
- GMC
- Mazda
- Skoda
Fault code P0612 can sometimes be found with other errors. The most common are the following: P060A, P060B, P060C, P060D, P060E, P060F, P0610, P0611.
