P0612 OBD-II Trouble Code: Fuel Injector Control Module Relay Control

P0612 code definition

The P0612 code represents that a problem has been detected within the relay control circuit of the fuel injector control module.

What the P0612 code means

The P0612 is usually triggered after the PCM detects that something isn’t working correctly with the fuel injector control module relay control circuit. One of the PCM’s supporting control modules may also detect this issue. Examples would be the body control module, the transmission control module, the instrument panel control module, the turbo control module, the fuel injection control module, the antilock brake control module, the cruise control module, the anti-theft module, proximity alert module, the traction control module, and the climate-control module.

In the event of a relay control error in the fuel injector control module, this code will be stored and a Check Engine Light will come on. However, for some models, this problem has to occur multiple times before the warning light is displayed.

What causes the P0612 code?

A number of issues could cause the P0612 code. The most common reasons would be:

• A bad fuel injection relay/fuse
• A malfunctioning fuel injector control module
• A poor electrical connection
• A loose control module strap or busted ground wire
  
• Corroded, shorted or open connectors or wiring in the CAN Bus harness
• A defective CAN bus

What are the symptoms of the P0612 code?

This code could produce a variety of symptoms. You will most likely notice some problems with drivability or difficulty shifting. Your vehicle’s engine may even stall on you or vibrate when you’re just sitting in idle. Poor acceleration is to be expected as well when something is wrong with a fuel injector.

Obviously, given the above, you will probably suffer from poor fuel economy until the problem gets fixed.

How does a mechanic diagnose the P0612 code?

Your mechanic will probably begin their diagnosis with an OBD-II scanner and a digital ohmmeter to ascertain all the codes stored in relation to this problem. Then they’ll carry out a visual inspection of every connection and wire.

It may also be necessary for them to disconnect and test every single one of the CAN bus pins, though this would take a lot of time.

Common mistakes when diagnosing the P0612 code

Codes like P0612 that have to do with communication failure are fairly easy to misdiagnose and, thus, perform an erroneous repair. One reason for this is that they’re so often accompanied by other problems.

In this case, P0612 is associated with some transmission and drivability codes, engine misfire codes, fuel injector codes, lead exhaust codes and many others. As a result, a mechanic may repair those issues and assume that the ones associated with the P0612 code.

Utilizing freeze frame data and addressing codes in the order in which they were stored will help a mechanic avoid this problem.

How serious is the P0612 code?

At the very least, as long as this code is present, your ability to drive your car is going to suffer. It’s not necessarily dangerous, but it could eventually evolve into something bigger and more expensive to fix. For instance, if you keep trying to force your vehicle to shift, it’s only going to be a matter of time before your gears become seriously damaged.

Of course, you’re also going to be wasting money at the pump because of the poor fuel economy related to this code.

What repairs can fix the P0612 code?

Your mechanic will carry out one or more of the following repairs:

• Replace or repair disconnected, damaged, corroded or shorted connectors, components and wiring
• Replace or repair the fuel injector
• Disconnecting the CAN bus pins

Additional comments for consideration regarding the P0612 code

Keep in mind that taking out all the pins from the CAN bus would take a very long time and not be very cost-effective, so every step should be taken to not take this step if possible.

Need help with a P0612 code?

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