This vehicle does not enter closed loop

MALLYBOY

MEMBER
2004 DODGE CARAVAN
3.3L
V6
2WD
AUTOMATIC
95,000 MILES

This vehicle does not enter closed instead when I start it in the morning and connect scanner and check fuel system statue, it says open loop due to insufficient engine temperature. When it warms up to normal engine temperature and it says open loop due to engine load. What is the cause of that engine load, while the A/C is not on and vehicle in park?
I attached the screenshot below to see what I am saying.

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7 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning,

What is the actual code that is set?

The low temperature is most likely from the thermostat opening too fast or stuck open. I would replace it with a 195 thermostat.

https://www.2carpros.com/articles/replace-thermostat

https://www.2carpros.com/articles/coolant-flush-and-refill-all-cars

It is common for cars to go into the open loop at idle under no load. As soon as you start driving it should go into a closed loop. Right now, you need to get the temperature up.

Let me know if you have any other questions.

Roy

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Sunday, March 6th, 2022 AT 5:12 AM

MALLYBOY

MEMBER
300 POSTS

Here are the codes:
1. P0201
2. P0480
3. P0499
There is no thermostat on the engine, I removed it since the fan control circuit from ECM fail, so I ground the line to fuel pump control relay. And sometimes the vehicle will rise temperature under Air condition.

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Monday, March 14th, 2022 AT 2:47 PM

ASEMASTER6371

MECHANIC
52,797 POSTS

Okay, first if you continue driving without a thermostat, you will damage the motor. It is required to be there for circulation of the coolant to the entire motor.

https://www.2carpros.com/articles/how-an-engine-thermostat-works

https://www.2carpros.com/articles/replace-thermostat

The code guides I attached below are for you. 201 is for number one injector. You need to verify battery voltage to the injector with the key on. Then you need a Noid light to be sure the ECM is commanding fuel from the injector.

The 480 is for the relay for cooling fans. I attached a wiring diagram of the cooling fans for you.

The 499 is an emissions code. You need to have the system smoke tested to find the source of the leak.

Roy

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Tuesday, March 15th, 2022 AT 1:52 AM

MALLYBOY

MEMBER
300 POSTS

The ECM is not commanding the injector, so I feed the Injector number 1 from cylinder 3, the ECM is not commanding the fan on, so I feed the control circuit from ECM to ground. I want to know why it doesn't enter closed loop or cause of engine load.

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Tuesday, March 15th, 2022 AT 5:53 AM

ASEMASTER6371

MECHANIC
52,797 POSTS

It may be the ECM itself. Under no-load conditions, it could go back to the open loop.

Try raising the RPM to 1200 and see if it switches to closed loop on your scan tool.

Roy