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Discussion Starter #61
Scooter don't know if your Nitro has been out of use for awhile and a valve is just stuck or if you need to replace the expensive HYDRAULIC CONTROL UNIT. Could your braking system just be low on fluid? Not much help, but here are some facts about the ABS system. What would happen if you just jammed on your brakes, could it free up the system? May be better to have a quality Dealer inspect and give you an estimate! Good Luck, sorry not to be of any help, but please let us know how your important issue is resolved.



Electronic Control Modules / MODULE, Anti-Lock Brake System / Operation
OPERATION

The ABM voltage source is through the ignition switch in the RUN position. The ABM contains dual microprocessors. A logic block in each microprocessor receives identical sensor signals. These signals are processed and compared simultaneously. The ABM contains a self check program that illuminates the ABS warning light when a system fault is detected. Faults are stored in a diagnostic program memory and are accessible with the scan tool. ABS faults remain in memory until cleared, or until after the vehicle is started approximately 50 times. Stored faults are not erased if the battery is disconnected.

Brakes / Brakes, ABS / Standard Procedure

STANDARD PROCEDURE - ABS BRAKE BLEEDING

ABS system bleeding requires conventional bleeding methods plus use of a scan tool. The procedure involves performing a base brake bleeding, followed by use of the scan tool to cycle and bleed the HCU pump and solenoids. A second base brake bleeding procedure is then required to remove any air remaining in the system.




1. Perform base brake bleeding,

PRESSURE BLEEDING

Special Tools: Click to display a list of tools used in this procedure








Use Mopar brake fluid, or an equivalent quality fluid meeting SAE J1703-F and DOT 3 standards only. Use fresh, clean fluid from a sealed container at all times.

Do not pump the brake pedal at any time while bleeding. Air in the system will be compressed into small bubbles that are distributed throughout the hydraulic system. This will make additional bleeding operations necessary.

Do not allow the master cylinder to run out of fluid during bleed operations. An empty cylinder will allow additional air to be drawn into the system. Check the cylinder fluid level frequently and add fluid as needed.

Bleed only one brake component at a time in the following sequence:

•Master Cylinder
•Right Rear Wheel
•Left Rear Wheel
•Right Front Wheel
•Left Front Wheel

Follow the manufacturers instructions carefully when using pressure equipment. Do not exceed the tank manufacturers pressure recommendations. Generally, a tank pressure of 103-139 kPa (15-20 psi) is sufficient for bleeding.

Fill the bleeder tank with recommended fluid and purge air from the tank lines before bleeding.

Do not pressure bleed without a proper master cylinder adapter. The wrong adapter can lead to leakage, or drawing air back into the system. Use adapter provided with the equipment or Adapter 6921 .



2. Connect scan tool to the Data Link Connector.




3. Select ANTILOCK BRAKES, followed by MISCELLANEOUS, then ABS BRAKES. Follow the instructions displayed. When scan tool displays TEST COMPLETE, disconnect scan tool and proceed.




4. Perform base brake bleeding a second time,(Refer to 05 - Brakes - Standard Procedure) .




5. Top off master cylinder fluid level and verify proper brake operation before moving vehicle.



Brakes / Brakes, ABS / Hydraulic/Mechanical / HYDRAULIC CONTROL UNIT (HCU) / Operation
OPERATION
Accumulators in the valve body store extra fluid released to the system for ABS mode operation. The pump provides the fluid volume needed and is operated by a DC type motor. The motor is controlled by the ABM.

The valves modulate brake pressure during antilock braking and are controlled by the ABM.

The HCU provides four channel pressure control to the front and rear brakes. Two channels control the rear wheel brakes individually. The two remaining channels control the front wheel brakes individually.

During antilock braking, the solenoid valves are opened and closed as needed. The valves are not static. They are cycled rapidly and continuously to modulate pressure and control wheel slip and deceleration.

During normal braking, the HCU solenoid valves and pump are not activated. The master cylinder and power booster operate the same as a vehicle without an ABS brake system.

During antilock braking, solenoid valve pressure modulation occurs in three stages, pressure increase, pressure hold, and pressure decrease. The valves are all contained in the valve body portion of the HCU.


PRESSURE DECREASE

The outlet valve is opened and the inlet valve is closed during the pressure decrease cycle.

A pressure decrease cycle is initiated when speed sensor signals indicate high wheel slip at one or more wheels. At this point, the ABM closes the inlet then opens the outlet valve, which also opens the return circuit to the accumulators. Fluid pressure is allowed to bleed off (decrease) as needed to prevent wheel lock.

Once the period of high wheel slip has ended, the ABM closes the outlet valve and begins a pressure increase or hold cycle as needed.


PRESSURE HOLD

Both solenoid valves are closed in the pressure hold cycle. Fluid apply pressure in the control channel is maintained at a constant rate. The ABM maintains the hold cycle until sensor inputs indicate a pressure change is necessary.


PRESSURE INCREASE

The inlet valve is open and the outlet valve is closed during the pressure increase cycle. The pressure increase cycle is used to counteract unequal wheel speeds. This cycle controls re-application of fluid apply pressure due to changing road surfaces or wheel speed.
 

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Discussion Starter #62
Nitro ABS Brake Error Codes


Apr 20, 2015
 

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Turned out they found a broken hose on the top of the fuel tank so far so good lets hope it's fixed nothing more annoying than a check engine light.. Thanks for all the input...
 

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Discussion Starter #64
Turned out they found a broken hose on the top of the fuel tank so far so good lets hope it's fixed nothing more annoying than a check engine light.. Thanks for all the input...
Thanks for your update, may help others!
 

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Thank you for getting back to us and posting your fix. So many times, people ask a question, and never get to the forum to post the outcome.

:cool:
 

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02 Sensors

I have replaced all 4 of the 02 sensors on ,my 07 Nitro,3.7ltr. put the CEL out, stayed off for about 5 minutes and came back on with the same (2) codes, P0038/P0038 P/d. If there is any help on this problem out there, it would be appreciated.
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Welcome rmadd!

From the codes we have listed it is a Heater Circuit High right? So are you looking for a heater control issue? Have you reset your system by disconnecting your battery and do you still have that error code?
 

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I have erased the codes with a scanner, CEL still on, Have disconnected the -battery cable for over an hour, CEL still on. I have replaced all the o2 sensors front and back on the exhaust system. Have checked the connection's all are tight. The code P0038 is for Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2. Is there a fuse for these sensors? Some post say there is some not, I can't find anything in the owners manual on this. Thanks for your reply. Your help is appreciated.
 

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I am having another type of problem, a new TPM sensor, the OEM sensor broke and I replaced it with an after market sensor. It was installed and it displays the corect PSI , but, every time I start My 07 Nitro, the display tells Me there is a problem with My TPMS????

any ideas??

Thanks
Rick
 

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Discussion Starter #71
I have erased the codes with a scanner, CEL still on, Have disconnected the -battery cable for over an hour, CEL still on. I have replaced all the o2 sensors front and back on the exhaust system. Have checked the connection's all are tight. The code P0038 is for Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2. Is there a fuse for these sensors? Some post say there is some not, I can't find anything in the owners manual on this. Thanks for your reply. Your help is appreciated.
Well I have looked everywhere, as I'm sure you have with no resolve. Guess you could have a defective sensor or a bad pigtail hookup, but doubtful. I even thought you might have 4.0 engine sensors instead of 3.7 engine ones, but at least here in the U.S. they appear to be the same. Only other thing I found was this issue can be caused by a dirty air filter. Guess not, right?
 

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Discussion Starter #72

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Cylinder #3 misfire P0303 error

I have a 2011 Nitro Heat 4x2 4.0L with 39,000 miles. Throwing code P0303. Battery checks out fine, alternator good, replaced all plugs with factory plugs, seafoamed the fuel, replaced coil pack at cylinder #3 with an autozone coil pack which is identical. Still getting error code on same cylinder after replacing.

My question is, did I put the new coil pack in the right place? where is cylinder #3? is it on the passenger side or the driver side? is it the one in the center on either side? or is it in front or towards back? is it the red one like shown on my image? (small image added for clarity)

any help in this matter is highly appreciated.

signed,
desperate
 

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Have you thought of taking the coil you took out and put it at the blue location?
 

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yes. I initially put it in the red location then moved it to the blue location but still getting P0303. I'm afraid i might have to try all of them but time is not on my side. Or is there a way of testing coils with the manifold and intake out the vehicle?
 

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Discussion Starter #76
yes. I initially put it in the red location then moved it to the blue location but still getting P0303. I'm afraid i might have to try all of them but time is not on my side. Or is there a way of testing coils with the manifold and intake out the vehicle?
Have you tried to reset your computer by disconnecting the battery to reset the error code?
 

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yes. I have reset the pcm by unplugging the battery everytime. How do i test each coil pack by unplugging one at a time to see which one is faulty? is this possible on a 4.0L?
 

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No, this is not possible on the 4.0 as you have to remove the plastic intake manifold to gain access. :(

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2009 Nitro - ANOTHER Cylinder #3 misfire - 3.7L V6

I noticed another guy in this forum posting about a cylinder 3 misfire, but mine is a little different than his.

I have the 3.7L V6 and mine is a 2009. I have the dual coil packs that control 2 spark plugs and no engine manifold cover.

I changed all the spark plugs and the dual coil pack on cylinder 3, and it seemed to make the problem worse. Bad idling issues, and it causes my transmission light to flash (probably because it's confused it's not getting the right amount of HP). I read the other message thread and disconnected the battery for 10 minutes, and it worked GREAT! I took it on the highway, revved the engine, and TRIED to get the check engine light to come back on, but I could not. Now I went to start it today and it went right back to it's old ways of misfiring and check engine lights just like after I changed the plugs and coil pack.

Do the wires connected to the coil pack go faulty often? Am I better off buying one at a dealership? How hard are they to change on your own?

Also does the Dodge Dealership have a specific diagnostic they can run that will tell them more than just a cylinder 3 misfire? Maybe I have a faulty fuel injector? If so they why did it run perfectly when I unhooked the battery?

Sorry thats a lot of questions, but I need HELP!!

Thanks SO much everyone!

- Nick in Oklahoma
 

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cranks continous no start any one have this issue?

I have an early build 2007 nitro with 3.7l v-6. my issue is it will crank w/no start. The problem seems to be very intermittent. only after a 40 min or more drive cycle. (going into a store) when I come back out 15-mins later is when the problem occurs. I keep a hand held scanner in the car, no pcm dtc's . I also keep a fuel pressure gauge in the car also I am trying to pin point the issue, but have not had any luck. as I go to check fuel pressure it starts immeadtly after connecting the gauge. The problem only occurs a couple times a month. I am suspecting the fuel pump, but have not ruled out a Tpim issue??? any one have similar issues???:confused:
 
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