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Jeremy
Jeremy, Certified Truck/Bus Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 2785
Experience:  ASE Med/HD Truck Technician, NATEF Diesel Engines and Electrical/Electronics Technician, EPA 608/609 HVAC Certified, Steering/Suspension and ABS/Brakes Technician
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I have a code on engine protect 71 and 83. Can you tell me

Customer Question

I have a code on engine protect 71 and 83. Can you tell me what those are for
Submitted: 10 months ago.
Category: Medium and Heavy Trucks
Expert:  Jeremy replied 10 months ago.

My name is ***** ***** I will assist you.

If you turn key on, does check engine light come on? If not, remove panel and chamge bulb. It is a mini bulb. Do that first. Then redo the code check and let me know what codes are yelliw and what codes are red. I kmow you have the 2 red active codes, but I want to rule out an imactive code because they both have multiple meanings depending on the inactive codes that you also have.

Expert:  Jeremy replied 10 months ago.

I see you viewed this and this is still showing as a open question due to no positive (3 stars or more) rating.

Did you still need assistance with this?

Customer: replied 10 months ago.
I replaced bulb the check engine gives me codes 87, 77, 39, 83, 81 engine protect gives me 25
Customer: replied 10 months ago.
I had an injector put in also before replacing bulb. Can u help with codes
Expert:  Jeremy replied 10 months ago.

Code 25 means there is no active codes. The rest are inactive that were never cleared or intermittent issue that is coming and going, not being active. If the check engine light is not on, then the codes are stored. If it is on, then there is something going on and it will need to be investigated more.

39 - there is no 39.

77 - Fuel temp high

81 - Exhaust temp voltage high

83 - Exhaust temp or external pump pressure high

87 - External Pump pressure sensor input voltage low

On all the 80 series codes, a laptop is needed for those are on the dpf and EGR system. The software will be needed to monitor that more deeply.

The fuel temp too high could be that you are running the tanks low often or from the bad injector that you replaced or a fuel pump issue. Most likely it is from the fuel injector you replaced and it is a stored code. I see them when I have bad injectors and I replace them.

Expert:  Jeremy replied 10 months ago.

CLICK HERE for code reference.

Customer: replied 10 months ago.
Okay, much check engine light comes on if I idle but once I go down the road maybe 15 minutes the light cuts off. Should I worry. The mechanic put the computer to it but he said it has no problems.
Expert:  Jeremy replied 10 months ago.

Most likely that is from the fuel temp sensor

I agree, I wouldn't worry about it at this time unless it is on all the time. The sensor os probably reading wrong which I wouldn't worry about until the oil change. This way you can have the truck down for it and the sensor as a scheduled instead of losing money for more sitting.

Customer: replied 10 months ago.
I just did my oil change this past weekend and did all the lubing. Would u be able to tell me where the fuel temp sensor is at? I would like to change it myself if possible. I usually get a couple of days off a week and I like doing most of the stuff myself
Expert:  Jeremy replied 10 months ago.

It is easy to change. It is on top of the fuel filter housing.

CLICK HERE

Customer: replied 10 months ago.
Good deal. Tomorrow I will go buy it and replace it. My truck has the filter that screws in on the bot***** *****ke an oil filter. I will hunt for it just hoping it's not to expensive. Thank you Jeremy
Expert:  Jeremy replied 10 months ago.

It should be fairly cheap. It will be one if the least priced sensors. I think I paid $24 for the last one I did. That is with tax.

Customer: replied 10 months ago.
Here at freighter and the guy said they only sell a sensor that is oil fuel and temp sensor that goes under fuel pump
Expert:  Jeremy replied 10 months ago.

The sensor is on top of the fuel filter housing. They could call it a fuel pressure sensor for they do the 2 different jobs. Show him the pic I sent earlier.

Customer: replied 10 months ago.
Okay, I just checked my truck and it only has two hoses. No sensor. There is one behind fuel pump that I bought it is under the tail if u want to call it that of the fuel pump. I noticed my check engine stayed on and I drove 80 miles today
Customer: replied 10 months ago.
Better picm
Customer: replied 10 months ago.
This is housing
Customer: replied 10 months ago.
That is fuel pump
Expert:  Jeremy replied 10 months ago.

What codes do you have for the check engine light?

Customer: replied 10 months ago.
Engine protect flashed a 27 first then never again. 77 39 83 81. Engine protect 87
Customer: replied 10 months ago.
I kept checking and it kept giving me 77 39 83 81. And 87 for engine protect which I believe is an active code
Expert:  Jeremy replied 10 months ago.

When the computer was on the truck, were these codes cleared and reset? You have all the original same codes. When you get multiple codes that come back after they have been reset that indicates a power issue to the ECM, a engine harness issue, or the ECM is starting to fail. That is not comfortable to read that the same codes keep re-appearing.

There is one sensor on the truck that can cause all these codes to keep coming back and that it the barometric pressure sensor. If it is dirty or readin bad, it will affect each on of those sensors and cause the codes to all come up intermittent. It is very simple to change. It is on the driver side on the intake manifold. You unplug it, use a crescent wrnech, pliers, or a fixed wrench and remove it. It unscrews. You then screw it back in and plug it in. Turn the key on, but do not start the truck. Cycle the key 4 times and then wait a minutes and cycle 6 times. This will get the ECM to calibrate to the sensor without a computer, then start teh truck to see if you get the codes. I bet that sensor is plugged up or reading wrong causing all these other codes. It is what tells the ECM on how to get everything else on the engine to perform and if it is reading wrong, it will cause most sensors to act up and the check engine light to do what it is doing.

CLICK HERE and look for sensor 13. That is where it is.

Expert:  Jeremy replied 10 months ago.

I can almost bet on that baro sensor acting up and that is causing the other issues. I'm guessing you went through different elevations on your travels today as well.

Customer: replied 10 months ago.
Should I try buying this sensor or should I try resetting it first?? Would u happen to know how much it is??
Customer: replied 10 months ago.
Mechanic said he cleared codes but they keep coming back
Expert:  Jeremy replied 10 months ago.

With the codes coming back, I would change the sensor. It will be around $40 for that one. It goes out often and Freightliner likes to take advantage on the price of it.

Customer: replied 10 months ago.
Will give a shot in the morning and see what it does. I have to turn key 4 times wait a minute and then do it six times then turn the truck on to synchronize right??
Expert:  Jeremy replied 10 months ago.

Correct. 4 times tells the ECM to activate all sensors for testing. 6 times tells the ECM to reset all active faults and parameters for stored running data. Then when you turn the key back to on, then start, it will then relearn the pressures.

You are basically getting rid of the stored data that the CM holds for how the truck is driven and resets all the sensors back to normal parameters for relearn mode. It is a way to get around using the computer to delete the driver data.

Customer: replied 10 months ago.
Cool deal. I will go get sensor in the morning and give it a shot.
Expert:  Jeremy replied 10 months ago.

Let me know how it does.

Thanks.

Customer: replied 10 months ago.
Will let u know tomorrow. Thanks
Expert:  Jeremy replied 10 months ago.

You're welcome.

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