GMC

GMC troubleshooting questions? Ask a mechanic for answers

Ask an Expert,
Get an Answer ASAP!

2005 Envoy Denali. Replaced Air Suspension Compressor with…

Customer Question
2005 Envoy Denali. Replaced Air...
2005 Envoy Denali. Replaced Air Suspension Compressor with identical part. Compressor turns on with manual inflation switch but does not pump up airbags when starting the vehicle. Power supply is good, ground is good, all fuses checked and are good. Doesn't seem to be sending any voltage to either leveling sensors. What am I missing?
Submitted: 2 years ago.Category: GMC
Show More
Show Less
Ask Your Own GMC Question
Answered in 6 hours by:
2/24/2016
GMC Mechanic: Christopher Trevino,
 replied 2 years ago
Christopher Trevino
Category: GMC
Satisfied Customers: 7
Experience: Field Service Technician at Crown Lift Trucks
Verified

Hello, I saw your question going unanswered and I wanted to assist you here. I've fixed a similar problem on a Cadillac Escallade, These systems tend to be similar, I wanted to see if I could help you here. Is your Denali giving you a "SERVICE RIDE CONTROL" or "SERVICE AIR RIDE" on the DIC display in the instrument cluster? If so you will need to use a certain type of scantool that will communicate with this ESC module to see what codes are active or stored in the module. The module closes the ground for the ALC relay circuit to power the compressor. If you can post the codes here , I can continue to assist you here. Thank you,

Ask Your Own GMC Question
Customer reply replied 2 years ago
No error messages on instrument panel regarding air ride system. I do have a "service airbag" message but I'm pretty sure it's referring to the actual SRS because the "bubble gum guy" light is on as well. Also, the air compressor manual switch has a light on it. If there are malfunction codes it's supposed to flash with 1 of 3 sequences depending on the code. It doesn't flash at all, so no codes. I just pulled the automatic sensor plugs and tested them. I'm getting 3 ohms of resistance coming in (sent from compressor) and nothing coming out, which to me would indicate the signal from the compressor is good. I had the same problem with the previous compressor which I thought the problem was but I'm having the same issue even after I replaced it with a new one. Ironically, from time to time that compressor would kick on and fill the airbags. After time, the truck would start to sag and the compressor would not be triggered. It's an intermittent problem. I removed and cleaned the ground to the vehicle frame because I suspected that could be the issue but not to my surprise it wasn't. I'm stumped.
GMC Mechanic: Christopher Trevino,
 replied 2 years ago

Ok got it , thank you for the details. take a look at the wiring diagrams I have posted here, If you can post the diagrams you have I'll compare the two. Here's what I got for an 04 Escallade ESV. If I cant help you here I'll re-submit your question so hopefully a GMC Tech can further assist you. I Just want to make sure you get taken care of first and foremost!

cf14cc74-5808-4fa7-8b03-...gifcf14cc7...gif9e8ce99c-5628-4616-99ce-...gif9e8ce99...gifaa1410f6-36db-4e50-a1f3-...gifaa1410f...gif
Ask Your Own GMC Question
GMC Mechanic: Christopher Trevino,
 replied 2 years ago

I got it , thank you. Have you tested resistance from the other side of the plugs from the level sensors. not the harness to the module , but the sensors themselves? I just wonder if they are open or shorted, 0.2 ohms would be shorted and OFL would be electrically open as I'm sure you already understand. Also, if you have the electrical pin breakdown for the compressor would help. If the exhaust solenoid fails , it shuts down the compressor as well. However manually closing the switch closes the ground to power up the compressor. You are pretty much doing what the module should be doing but it cant because its not getting the correct inputs from either the steering sensors (if applicable ), level sensors, exhaust solenoid ect. I"d like to see what codes are present , The SRS codes may also interfere with this operation. I would start ohm testig the level sensors and any component possible related to the compressor for opens or shorts, then if still inconclusive , scan all the codes present on the truck to see what the module is seeing and that should guide you in the right direction.

Ask Your Own GMC Question
Customer reply replied 2 years ago
In the schematic I sent you, there are 2 plugs. 1 has 8 pins labeled A-H and the other has 3 A-C. I haven't tested the resistance on the sensors themselves because if they were bad I'm supposed to get either the service air ride message and/or the blinking light on the manual air switch. Also, if one goes bad the vehicle reads off the working sensor for both sides, but then again, it's supposed to show a fault that a sensor is not relaying feedback. I've test the exhaust valve, it works. The end of the exhaust line is located next to the manual air switch and I can here it exhaust when I manually turn the switch off and on. What I'm trying now is, I jacked up the body to what is called "D Height" and am resetting the ecu to try to get it to recalibrate or learn the height to see if that works. Being that the vehicle is sagging very low I'm hoping that once I lower it, the recalibration will trigger the compressor and fill the bags.
GMC Mechanic: Christopher Trevino,
 replied 2 years ago

That sounds like a plan, next chance you get , with all the connectors plugged together , back probe points H and D you should get 12volts. and with the key in the run position, points G and D you should get 12 volts. By the way, you don't happen to be in any freezing weather conditions? Freezing temps seem to lock the compressors up. Usually below (25deg). Let me know how it goes, ill check back tomorrow. Best of luck!

Ask Your Own GMC Question
Was this answer helpful?
Ask Gm Tech (Cam) Your Own Question
Gm Tech (Cam)
Gm Tech (Cam)
Gm Tech (Cam), GMC Mechanic
Category: GMC
Satisfied Customers: 1,780
1,780 Satisfied Customers
Experience: GM Grand Master Technician 2007. 14 year experience.

Gm Tech (Cam) 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

1,780 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
GM 3500 hd: 2013 gmc 3500hd, reductant tank heater went out,
2013 gmc 3500hd, reductant tank heater went out, replaced it no has service exhaust fluid see owners manual on dash. ???… read more
Michael Moore
Michael Moore
Team leader, bumper to bumper tech.
Associate Degree
1,323 satisfied customers
EGR valve location / removal for 2007 GMC Duramax
EGR valve location / removal for 2007 GMC Duramax… read more
Dave Nova
Dave Nova
GMC Technician
Associate Degree
929 satisfied customers
I have a brand new 2016 Yukon Denali. There is a rattle in
I have a brand new 2016 Yukon Denali. There is a rattle in back that sounds like it's coming from the 3rd row. Are you familiar with this issue? It's driving me crazy.… read more
Chris (aka-Moose)
Chris (aka-Moose)
GMC Technician
Vocational, Technical or Trade School
583 satisfied customers
Service exhaust fluid light came on read the code and it
Service exhaust fluid light came on read the code and it said reluctant heater we replaced that but do not know how to reset the system, engine is limited to 4 mph. … read more
Jerry Newton
Jerry Newton
Vocational, Technical or Trade Scho
2,066 satisfied customers
Exhaust valve on #6 will not hold compression 62000 miles on
Exhaust valve on #6 will not hold compression 62000 miles on car … read more
Gary
Gary
ASE Certified Technician
Vocational, Technical or Trade Scho
1,557 satisfied customers
Exhaust gas temp. sensor #1 where is it? Egr has been
yes egr has been replaced and clogged, engine code from dealer said exhaust gas temperature sensor #1 … read more
Todd Audette
Todd Audette
Automotive Technician
Vocational, Technical or Trade School
362 satisfied customers
I have a 2015 GMC Denaili 2500hd the exhaust fluid is
Second opinion] I have a 2015 GMC Denaili 2500hd the exhaust fluid is showing 42 miles before dropping to 4 mph what can I do… read more
Gm Tech (Cam)
Gm Tech (Cam)
GMC Mechanic
1,780 satisfied customers
I have a 2015 GMC Denaili 2500hd the exhaust fluid is
I have a 2015 GMC Denaili 2500hd the exhaust fluid is showing 42 miles before dropping to 4 mph what can I do … read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 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
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
446 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
1,949 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
I have a 2015 GMC 2500 HD. My message was exhaust fluid
I have a 2015 GMC 2500 HD. My message was exhaust fluid system loss of power so I filled the DEF. It's been 2 days and it still won't reset even when I did everything according to the manuel. Can I re… read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
GMC Sierra 2500 HD: my 2003 duramax has lost fuel economy from
my 2003 duramax has lost fuel economy from 19 mpg to 14.5 mpg. two dealerships have analyzed it and said injectors are ok. you can see lots of fumes when taking off and black smoking bad when pulling … read more
Gm Tech (Cam)
Gm Tech (Cam)
GMC Mechanic
1,780 satisfied customers
Working on a 2012 2500 GMC with the 6.6 duramax got a # 4
Working on a 2012 2500 GMC with the 6.6 duramax got a # 4 exhaust sensor reading 1832 degrees well the others are reading from 120 to 201 is this reading way to high and it is setting a P20B9 code and… read more
Chris (aka-Moose)
Chris (aka-Moose)
GMC Technician
Vocational, Technical or Trade School
583 satisfied customers
GMC 2015 Duramax LML V8 6.6L - DIC message SERVICE EXHAUST
GMC 2015 Duramax LML V8 6.6L - DIC message SERVICE EXHAUST FLUID SYSTEM - SEE OWNERS MANUAL . Filled DEF reservoir. Was not empty. Drove 60 miles still did not reset. Warning that it will reduce MPH t… read more
BOBBYSS
BOBBYSS
TECHNICIAN/ADVISOR
Associate Degree
8,343 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
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