[+Quick Fixing] P1222 Cummins Code: What Are The Common Symptoms?

Why do you see the P1222 Cummins Code? This code is usually displayed on Cummins engines because of defective fuel injectors, poor electrical connections, faulty injector wire harnesses, or abnormal fuel flow.

Anyway, this article will be a complete guideline on the P1222 error code for Cummins engine. Here, we have listed all possible reasons for this code and the symptoms and solutions. So, let’s get started with the main discussion without any further ado.

P1222 Cummins Code: 5 Reasons With Symptoms & Fixes

These are the most common reasons and symptoms for displaying the P1222 code in your Cummins engine:

Reasons for P1222 CodeCommon Symptoms
Dirty or defective fuel injectorsWarning light for ‘Engine Service Soon
Poor electrical connection on fuel injector circuitThe engine light is on
Shorted or open fuel injector wire harnessEngine misfiring
After reprogramming the Engine Control Module (ECM)The engine light is on
Abnormal return of fuel to the tankThe WTS light is always on

Don’t finish here. Continue your reading to know the most straightforward fixes for the P1222 trouble code.

Dirty Or Defective Fuel Injectors

Defective fuel injectors are the most common reason for displaying the P1222 code in your vehicle. It is most likely that your fuel injector is faulty if you receive an engine service alert. Before replacing or rebuilding a fuel injector, we recommend cleaning it first. Dirty fuel injectors are sometimes the cause of this error code.

Before cleaning the fuel injectors, disconnect the fuel pump. The fuel pump stops the flow of fuel when we start the Cummins engine. Next, remove the fuel line. Now we need an adapter, and it’s very easy to make.

Glue the hose to the straw that comes with a carp cleaner, then place it on your vehicle’s fuel rail. The carp cleaner pressure causes the skirt to be pushed downwards, so you need to use the hose clamped skirt. You also need to spray a few times to generate enough pressure to start a Cummins engine.

Now, the engine is running, and the fuel line is disconnected, so the engine is running on the cleaner. If the cleaner can’t provide enough pressure for the engine to run smoothly, it will shake, and the engine will shut down. And you need to wait for this to happen. After that, we are done.

Hopefully, the Dodge Cummins P1222 code will disappear after the fuel injectors have been cleaned. If it does not, you will have to replace or repair the defective fuel injectors.

Poor Electrical Connection On Fuel Injector Circuit

With this problem, the engine light will come on, and at the same time, you will receive the code P1222. We will show you a simple but effective test to identify the poor electrical connection on the fuel injector circuit.

To perform the test, you require a cheaper cheerful electrical tester. You will look at the upside-down horseshoe as ohms on your tester to check the injector’s electrical resistance on the inside. Now, set your test meter to ohms. However, the readings you’re looking for are anywhere between sort 160 to 180 or maybe 190.

So, all you do inside the tip of the injector, then you will see two electrical connectors. It doesn’t matter which way you check because you’re only checking Ohms reading. Just put them together and check the voltage reading. It should stay between 170 and 180, but there is a problem with the injector if it goes straight to zero.

To test if there is a fault with it, leave one of the connectors on one of the testers and touch it on the injector’s body. Still, suppose you don’t get any readings. In that case, you may have broken wires inside or the electromagnet inside, which would result in a bad electrical connection on the fuel injector circuit.

Shorted Or Open Fuel Injector Wire Harness

2005 Dodge Cummins P1222 codes may be displayed due to shortened or open fuel injector wire harnesses. In that case, first, check the connectors and wiring harnesses visually to locate the area. Then do a simple test in order to fix the problem.

Activate the Ohms setting on your multimeter. Connect your multimeter to the fuel injector plug terminal. Then analyze how much Ohms the fuel injector produces. Keep a record of the reading. Check the Ohm readings of all the fuel injectors and compare their values with each other.

The fuel injectors in operation should have the same Ohm value or very nearly so. Injectors with too little or too much resistance will have a different Ohm value than others. If an injector’s Ohm value is significantly different from other injectors, you have to replace it as early as possible to get rid of the P1222 code.

After Reprogramming The Engine Control Module (ECM)

In some cases, you can get the P1222 code in your Cummins engine because of reprogramming the ECM. ECM programming is a complex process that should not be attempted without a dealer’s assistance.

However, many of you attempt to reprogramme the ECM on your own and often fail to get the job done correctly. As a result, you may notice the trouble code P1222 in your vehicle with the symptoms of an engine light on.

Anyway, if you face this problem, it would be best if you spoke with a dealer for correct ECM reprogramming. And our advice is not to try to reprogramme an ECM yourself because most of the time, it ends with a mess.

Abnormal Return Of Fuel To The Tank

A Cummins engine that doesn’t start or run correctly can be attributed to an abnormal fuel return to the tank. That’s why make sure the fuel tank is sufficiently filled and run a diagnostic on the actual pressure of the pump to rule it out.

You also know that sufficient fuel is required to keep the engine running. So, the fuel tank breather should be checked for blockages as well as the supply pipes. In order for Cummins diesel engines to function correctly, the fuel quality needs to be high.

Also Read: P1693 Dodge Cummins: Why You See This Trouble Code?

A WTS light always appears if there is an abnormal fuel return to the tank. And also causes issues such as loss of fuel pressure, a drop in flow and delayed injection, sluggish operation, or a complete halt of the engine. The trouble code P1222 will be generated as a result. For that, it is necessary to replace the fuel injectors in order to restore normal fuel flow.

Frequently Asked Questions (FAQs)

What Does P1222 Code Mean?

P1222 code indicates a throttle circuit problem. Generally, when a leak occurs at idle PRV, the P1222 error code appears. The Engine Control Module cuts off the power to the throttle control motor if the P1222 error code is stored. In this way, it protects the expensive Cummins engine by preventing defective parts from being driven.

How To Fix Code P1222?

Check the wire harness and connectors visually. Ensure that the connectors are in good working order and that there are no broken, bent, pushed out, or corroded pins. Whenever any issue is detected with fuel injectors or wires, they need to be replaced as soon as possible.

Final Verdict

The P1222 Cummins code usually indicates a more severe and expensive problem. Take this code seriously, and use our guide to correctly diagnose it. If the fixing process looks difficult to you, then it is wise to visit a dealer.

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D Conroy

Meet our senior writer and content manager of Automasterx. He has worked in several mechanical garages and mastered different vehicle diagnoses and parts repair. He never stops until finding out the ultimate solutions for any vehicle fault code. However, ensuring the only solid solutions for each vehicle malfunction is his core part of the duty, alongside analyzing fault codes and signals.

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