GMC

GMC Troubleshooting Questions? Ask a Mechanic for Answers

Ask an Expert,
Get an Answer ASAP!

GMC

I have a 2004 GMC with a 6.6 Duramax diesel code p1404 egr 2

Customer Question
position error/egr- closed performance...
I have a 2004 GMC with a 6.6 Duramax diesel code p1404 egr 2 position error/egr- closed performance
Submitted: 1 year ago.Category: GMC
Ask Your Own GMC Question
Answered in 10 minutes by:
11/22/2016
GMC Mechanic: Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems replied 1 year ago
Chad Farhat
Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems
Category: GMC
Satisfied Customers: 4,600
Experience: Owner at Carolina Auto Service &Sales , 20 years Experience in Foreign & Domestic vehicles
Verified

Hi, I'm Chad. Welcome to JustAnswer. I'm reviewing your question and I will be posting your reply ASAP.

Ask Your Own GMC Question
GMC Mechanic: Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems replied 1 year ago

hey how are you

i sent you 4 diagrams showing the test needs done to determine is it : is it a stuck open egr vent solenoid ,restricted exhaust causing high pressure , egr vacuum control etc...

The content of this article/image reflects the changes identified in TSB:06_06_04_022 Dated 04/12/2006

DTC P1404 CIRCUIT DESCRIPTION The exhaust gas recirculation (EGR) valve is vacuum operated. Vacuum for the EGR valve control system is supplied by a belt driven vacuum pump. The EGR valve vacuum control solenoid and the EGR valve vacuum vent solenoid work together to control the position of the EGR valve. The engine control module (ECM) monitors the EGR vacuum sensor signal to determine the amount of vacuum that is applied to the EGR valve. The ECM uses the mass air flow (MAF) sensor to calculate the amount of exhaust gas that is consumed by the engine. When the EGR valve is opened, the MAF rate will decrease. If the EGR vacuum sensor signal is higher than desired and the MAF rate is lower than expected, it is assumed that the EGR valve is not closing due to a vacuum problem and DTC P1404 sets.

CONDITIONS FOR RUNNING THE DTC - DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0405, P0406, P0489, P0490, P0500, P0651, P2142, P2144, P2144, and P2145 are not set. - The EGR valve vacuum control solenoid has been commanded to more than 70 percent. - The PCM is not in the Reduced Engine Power mode. - The BARO parameter is more than 72 kPa. - The Engine Speed parameter is between 610-820 RPM and is steady within 50 RPM for more than 3 seconds. - The ECT Sensor parameter is between 60-100°C (140-212°F). - The Calculated Fuel Rate parameter is between 3-20 mm(3). - The power take off (PTO) is disabled, if equipped. - The IAT Sensor parameter is more than 0°C (32°F). - The APP Indicated Angle parameter is less than 1 percent. - The Ignition 1 Signal parameter is between 11-18 volts. - The Vehicle Speed Sensor parameter is less than 0.40 km/h (0.25 mph). - The Engine Run Time parameter is more than 5 seconds. - All of the above conditions are met for more than 3 seconds. CONDITIONS FOR SETTING THE DTC - The ECM detects a higher than desired EGR vacuum sensor signal and a lower than expected MAF rate. - The above conditions are met for more than 4 seconds.

ACTION TAKEN WHEN THE DTC SETS - The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. - The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. CONDITIONS FOR CLEARING THE MIL/DTC - The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. - A current DTC, Last Test Failed, clears when the diagnostic runs and passes. - A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. - Clear the MIL and the DTC with a scan tool.

DIAGNOSTIC AIDS Inspect for the following conditions: - A stuck open EGR vacuum vent solenoid. - A stuck open EGR valve vacuum control solenoid. - Proper vacuum line connections. - A restriction in the exhaust system causing high back pressure.

TEST DESCRIPTION

Zoom and Print Options

Steps 1-2

Zoom and Print Options

Steps 3-4

Zoom and Print Options

Steps 5-9

Zoom and Print Options

Steps 10-11

The numbers below refer to the step numbers on the diagnostic table.
3. The EGR vacuum vent solenoid is normally closed. When the EGR vacuum vent solenoid is closed, it will vent to atmosphere. Therefore it should not hold vacuum with this test.
4. The EGR valve vacuum control solenoid is normally closed. When vacuum is applied to the commanded open EGR vacuum vent solenoid it should hold vacuum. If the vacuum does not hold, then a stuck open EGR valve vacuum control solenoid is indicated.

Please let me know if you need anything else on it, just reply back and we will continue

If you are good, Please Kindly Rate Me.

A 5 Star Rating is much Appreciated

If you feel I have not been helpful Please DO NOT RATE ME BAD OR POOR (1 or 2 stars) ,You can always ask me again or I can opt out of your question & open it for another expert ,that will provide you with more or better assistance on this issue

Please keep in mind that when you rate me , it does not end our conversation.

you can always come back to this conversation and ask me any follow up question you may have on this issue

(you can copy this link page & paste it in your browser when ready and it will open up our conversation again)

Thank You
Chad Farhat
ASE Certified Technician

6e8268d9-9b3d-48bc-a826-...gif6e8268d...gifb4a4376a-e6fc-4c3c-92cc-...gifb4a4376...gif975aede9-ae9f-4708-bdb9-...gif975aede...giff34c3040-31a2-477c-8b7f-...giff34c304...gif
Ask Your Own GMC Question
Customer reply replied 1 year ago
I changed the the egr- it is vacuum operated and it came with actuator when I control it with my scanner It Moves In and Out
GMC Mechanic: Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems replied 1 year ago

1-ok, that is good on egr ,so that is functioning when commanded ?

2-but is functioning when it needs to function? is the pcm controlling the solenoid when needed ? I sent you the EGR circuit digarma and the connection to the PCM

if you confident the egr system is working move to the exhaust restriction inspection

3- i sent you egr vacuum routing and components , check if routed correctly ,

4- this the EGR system description operation , please review

EXHAUST GAS RECIRCULATION (EGR) SYSTEM DESCRIPTION The exhaust gas recirculation (EGR) system is used to reduce the amount of nitrogen oxide (NOx) emission levels caused by combustion temperatures exceeding 816°C (1,500°F). It does this by introducing small amounts of exhaust gas back into the combustion chamber. The exhaust gas absorbs a portion of the thermal energy produced by the combustion process and thus decreases combustion temperature. The EGR system will only operate under specific temperature, barometric pressure and engine load conditions in order to prevent driveability concerns and to increase engine performance. The EGR system consists of the following components: EGR Valve The EGR valve is vacuum operated. The EGR valve is used to transmit exhaust gases from the exhaust system to the intake manifold to be recirculated into the combustion process. Vacuum Pump Vacuum for the EGR vacuum control system is created by a belt driven mechanical pump called a vacuum pump. When the engine is running, the vacuum pump is operating at all times. EGR Valve Vacuum Control Solenoid The EGR valve vacuum control solenoid is located in the EGR vacuum control system between the vacuum pump and the EGR vacuum vent solenoid. The ECM pulse width modulates (PWM) the ground path of the EGR valve vacuum control solenoid allowing metered vacuum from the vacuum pump to open the EGR valve to the desired position. The EGR valve vacuum control solenoid is supplied ignition voltage through the ignition 1 voltage circuit from the Fuel HT fuse. The EGR valve vacuum control solenoid is normally closed. EGR Vacuum Vent Solenoid The EGR vacuum vent solenoid is located between the EGR valve vacuum control solenoid and the EGR vacuum sensor. The ECM opens the EGR vacuum vent solenoid, allowing vacuum from the vacuum pump to build in the EGR vacuum control system. When the EGR vacuum vent solenoid is commanded closed, the EGR vacuum control system is vented to atmosphere which will cause the EGR valve to close very fast. The ECM controls the EGR vacuum vent solenoid by switching the ground path ON and OFF. Ignition voltage is supplied through the ignition 1 voltage circuit from the Fuel HT fuse. The EGR vacuum vent solenoid is normally closed. EGR Throttle Valve Vacuum Control Solenoid The EGR throttle valve vacuum control solenoid is located in the EGR vacuum control system between the vacuum pump and the EGR throttle valve. The ECM opens the EGR throttle valve vacuum control solenoid, allowing vacuum from the vacuum pump to close the EGR throttle valve. Diesel engines do not create enough engine vacuum on their own to allow the EGR gases into the combustion process. The EGR throttle valve, when closed, creates a restriction of incoming fresh air to the engine in order to create engine vacuum. When the ECM commands the EGR valve to open, the EGR throttle valve will be commanded closed. The ECM controls the EGR throttle valve vacuum control solenoid by switching the ground path ON and OFF. Ignition voltage is supplied through the ignition 1 voltage circuit from the Fuel HT fuse. The EGR throttle valve vacuum control solenoid is normally closed. EGR Vacuum Sensor The EGR vacuum sensor is located in the EGR vacuum control system between the EGR vacuum vent solenoid and the EGR valve. The ECM uses the EGR vacuum sensor to monitor the amount of vacuum that is available to the EGR valve. The ECM will make adjustments to the EGR vacuum control system in order to obtain the vacuum level necessary to achieve the proper EGR valve position. The EGR vacuum sensor is interfaced with the ECM by a 5-volt reference circuit, a low reference circuit and a signal circuit. MAF Sensor The MAF sensor is located in the air intake system between the air filter and the EGR valve out-take port. The ECM monitors the Mass Air Flow (MAF) sensor signal to calculate the actual amount of EGR flow into the intake manifold. When the EGR valve is opened, the MAF rate will decrease. When the EGR valve vacuum control solenoid is operated at 50-70 percent duty cycle, the MAF rate should drop at least 4 g/s. EGR Valve Cooler The EGR valve cooler is mounted on the right intake manifold, between the EGR valve and the exhaust pipe. Engine coolant flows through the EGR valve cooler in order to lower the exhaust gas temperatures before it enters the EGR valve and intake manifold. ECM The PCM calculates the amount of EGR needed based on the following inputs: - The accelerator pedal position (APP) sensor - The barometric pressure (BARO) sensor - The boost sensor - The engine coolant temperature (ECT) sensor - The exhaust gas recirculation (EGR) vacuum sensor - The intake air temperature (IAT) sensor - The mass airflow (MAF) sensor - The vehicle speed sensor (VSS) - The engine speed

2- Next Check the exhaust system ,did you check for restriction ?

Ask Your Own GMC Question
GMC Mechanic: Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems replied 1 year ago

hey ,just checking on you & see if you need additional help on it

Please let me know if you need anything else on it, just reply back and we will continue
A 5 Star Rating is much Appreciated
Please keep in mind that when you rate me , it does not end our conversation.
you can always come back to this conversation and ask me any follow up question you may have on this issue
(you can copy this link page & paste it in your browser when ready and it will open up our conversation again)
Thank You
Chad Farhat
ASE Certified Technician

Ask Your Own GMC Question
Ask Chad Farhat Your Own Question
Chad Farhat
Chad Farhat
Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems
Category: GMC
Satisfied Customers: 4,600
4,600 Satisfied Customers
Experience: Owner at Carolina Auto Service &Sales , 20 years Experience in Foreign & Domestic vehicles

Chad Farhat is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

He answered my question promptly and gave me accurate, detailed information. If all of your experts are half as good, you have a great thing going here.

DianeDallas, TX

< Previous | Next >

Meet the Experts:

Gm Tech (Cam)

Gm Tech (Cam)

GMC Mechanic

1,696 satisfied customers

GM Grand Master Technician 2007. 14 year experience.

Gary

Gary

ASE Certified Technician

1,557 satisfied customers

GCM master tech over 25 years

Dave Nova

Dave Nova

GMC Technician

929 satisfied customers

ASE Master Certification. GM World Class Certification

Chris (aka-Moose)

Chris (aka-Moose)

GMC Technician

583 satisfied customers

16 years of experience

Ron Z.

Ron Z.

- GMC Tech -

259 satisfied customers

18+yrs experience. State Inspector & GMC Diagnostics/Repair

George H.

George H.

ASE MasterTechnician

227 satisfied customers

15+ Years ASE Master Technician with Level 1 Certification

Don - Mo Lurch

Don - Mo Lurch

ASE Certified Technician

218 satisfied customers

GM, GMC, Chevrolet Cert., Heavy Line Mech, Race Shop Owner, Mobile Electronics

< Previous | Next >

Related GMC Questions
03 envoy, 4.2 L engine, dealer replaced the thermostat
03 envoy, 4.2 L engine, dealer replaced the thermostat housing then told me that a freeze plug has blown out. does this block have freeze plugs? … read more
Todd M
Todd M
Owner
ASE Certification
1,492 satisfied customers
The check engine light came on and when I plugged in my
The check engine light came on and when I plugged in my INNOVA tester it showed a code that was either POIFO or PO1FO and I was trying to see what that code was for … read more
David Craig
David Craig
OWNER/MECHANIC
Associates
4,429 satisfied customers
Check engine light is on. Message: engine reduced power
check engine light is on. Message : engine reduced power loss, gmc Yukon denali 2007 … read more
Ron Z.
Ron Z.
- GMC Tech -
Vocational, Technical or Trade Scho
259 satisfied customers
Coolant leaking around right bank second from front
Coolant leaking around right bank second from front injector, we pulled the injector and we see coolant at the bottom of the hole, please advise? … read more
TIM MOHR
TIM MOHR
SHOP OWNER
Master's Degree
8,037 satisfied customers
Diesel exhaust system service? speed limited to 4mph and i
diesel exhaust system service? speed limited to 4mph and i am 20 miles from town … read more
Chris (aka-Moose)
Chris (aka-Moose)
GMC Technician
Vocational, Technical or Trade School
583 satisfied customers
2013 gmc duramax diesel: service exhaust fluid system
2013 gmc duramax diesel: service exhaust fluid system warning light and states will reduce speed. Filled DEF tank, warning persists … read more
Chris (aka-Moose)
Chris (aka-Moose)
GMC Technician
Vocational, Technical or Trade School
583 satisfied customers
I have a 2006 gmc sierra with 5.3 engine is it normal for
I have a 2006 gmc sierra with 5.3 engine is it normal for the coolant fans to kick on when temp is over 210 with a.c. off … read more
Eric
Eric
Retired
N/A
14,436 satisfied customers
Getting a service message on my exhaust fluid system and is
getting a service message on my exhaust fluid system and is transitioning to 65mph … read more
Gabriel Grey
Gabriel Grey
Master Service Technician
Associates
378 satisfied customers
I have a 2011 diesel 6.6 it's wasting coolant and the oil
I have a 2011 diesel 6.6 it's wasting coolant and the oil seems with water, also the pression coolant reservoir is black and oily. can you tel me if the problem is in the heads or in the engine block?… read more
Eric
Eric
Retired
N/A
14,436 satisfied customers
How much does it cost to replace a timing solenoid exhaust.
how much does it cost to replace a timing solenoid exhaust … read more
Gunvir Singh
Gunvir Singh
1,817 satisfied customers
2006 GMC savana 3500 6.6 low coolant light res was replaced
2006 GMC savana 3500 6.6 low coolant light res was replaced varified sensor open and closes replaces connector (broken wire) check resisdence on ground good and green wire to pcm replaced pcm and flas… read more
Jerry Newton
Jerry Newton
Vocational, Technical or Trade Scho
2,066 satisfied customers
Need to know how to reset diesel exhaust fluid system, Yes
Need to know how to reset diesel exhaust fluid system … read more
dustin barnhardt
dustin barnhardt
6 satisfied customers
Need an exhaust pressure differential pipe for a 2013 GMC
need an exhaust pressure differential pipe for a 2013 GMC 3500HD... … read more
Chris (aka-Moose)
Chris (aka-Moose)
GMC Technician
Vocational, Technical or Trade School
583 satisfied customers
09 buick enclave 3.6, code P000D exhaust camshaft position
09 buick enclave 3.6, code P000D exhaust camshaft position slow response bank 2, per autozone scanner. Could this be fixed by replacing sensor and if so where is it located? … read more
Ron Z.
Ron Z.
- GMC Tech -
Vocational, Technical or Trade Scho
259 satisfied customers
I'm replacing my coolant hoses. How do remove the surge tank
I'm replacing my coolant hoses. How do remove the surge tank to access the hose connected to the bottom of it? … read more
tim37857
tim37857
Mechanic
High School or GED
71 satisfied customers
I have 2011 2500 with Duramax. DIC display "Exhaust Fluid
I have 2011 2500 with Duramax. DIC display "Exhaust Fluid Empty Refill Now-Speed Limited to 55". I have added DEF fluid and ran the truck for about 50 miles. Have turned it off and restarted it severa… read more
Chris (aka-Moose)
Chris (aka-Moose)
GMC Technician
Vocational, Technical or Trade School
583 satisfied customers
My 2010 Duramax flashed the Clean Exhaust Filter message but
My 2010 Duramax flashed the Clean Exhaust Filter message but then within seconds it went into Reduced power Mode. I was on my way home from work so I drove about 25 miles at highways speeds and the Re… read more
Gm Tech (Cam)
Gm Tech (Cam)
GMC Mechanic
Vocational, Technical or Trade Scho
1,696 satisfied customers
My truck is turn on exhaust fluid quality por and my truck
My truck is turn on exhaust fluid quality por and my truck only can move by 6km ?h onlpls help. thanks sorry my English not very good … read more
sprinkles08
sprinkles08
Technician
High School or GED
11 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x