Top 20 2003 Hummer H2 Questions & Answers

cranks fast every time , starter motor cranks the engine fast , not slow, or dead starteror cranks fast, starts and stalls in 2 secondsand fast right foot actions can not prevent the stall?yes ,yes,, look at dash IP cluster see IMMO lampif IMMO lamp fails (security) then try the 2nd key Chevy gave you day 1 new. both keys fail>? oopsteeh guide is H2 ,free from Chevysecurity key called PASS_LOCK(tm)page 2-19 in the manualread it. https://experience.gm.com/bypass/pcf/gma-content-api/resources/sites/GMA/content/staging/MANUALS/0/MA358/en_US/2.0/2k03hummer.pdfDuring normal operation, the security light will turn offapproximately five seconds after the key is turned to RUN.beyond all that there are 50 things to make engine not run, GOT TOOLS> (lots of em)? Ill not guess all 50 and post them but can.

Blend Door Actuator Servos not working or Blend Doors off their mountings.

You replaced the fuel gauge stepper motor two times ? Did you do it correctly ? Fuel Gage The IPC displays the fuel level as determined by the PCM. The IPC receives a class 2 message from the PCM indicating the fuel level percent. The fuel gage defaults to empty if: • The PCM detects a malfunction in the fuel level sensor circuit. • The IPC detects a loss of class 2 communications with the PCM. When the fuel level is less than a pre-determined value, the low fuel indicator illuminates. Reviewing the fuel system description will further explain how the system functions. Refer to Fuel System Description . Did you try replacing the fuel level sensor ? Check for DTC'S diagnostic trouble codes ?

The crankshaft position sensor could be the cause , but without testing that would just be a guess . There are videos on youtube for testing GM ignition systems .

That means your horn and electrical to the horn are good. You may have a bad clock spring under the steering wheel, or a bad switch. Don't forget to check the horn fuse. It may have a different circuit than the FOB.

That's not how wiring diagrams are drawn. They're drawn by system, not location. See this post on how to get the diagram you're looking for

Do you have an air bag light lit on the instrument cluster ? Do you have C.C. button's on the steering wheel , do they work ? If the alarm fob (as u call it ) Can make the horns sound , the relay is sending B+ voltage to the horns Don't know how your testing. System Description The horn system consists of the following components: • Horn fuse • Horn relay • Horn switch • Horn(s) • Body Control Module (BCM) System Operation The vehicle horns are activated under the following conditions: • The horn switch is depressed. • The body control module (BCM) commands the horns on. The BCM commands the horns on under either of the following conditions: - When the content theft deterrent system detects a vehicle intrusion. For further information, refer to Content Theft Deterrent (CTD) Description and Operation in Theft Deterrent. - When the panic button is depressed on the remote control door lock transmitter. For further information, refer to Keyless Entry System Description and Operation in Keyless Entry. - When the OnStar® system is used to sound the horns, if equipped. For further information, refer to OnStar Description and Operation in Cellular Communications. - When the keyless entry system is used to lock the vehicle, a horn chirp may sound to notify the driver that the vehicle has been locked. The notification feature may be enabled or disabled through personalization. For further information, refer to Keyless Entry System Description and Operation in Keyless Entry. Circuit Operation Battery positive voltage is applied at all times to the horn relay coil and the horn relay switch. Pressing the horn switch applies ground to the horn relay control circuit. The body control module BCM may also apply ground to the horn relay control circuit as described above. When the horn relay control circuit is grounded, the horn relay is energized and battery positive voltage is applied to the horn(s) through the horn control circuit. The horn(s) sound as long as ground is applied to the horn relay control circuit.

Go to local dealer, parts department, ask staff to print an assembly diagram which includes all the parts and how they connected to the others, from it, you can see where the bolt/nut are, you can then remove and install a new one if it can be accessed, you decide to diy or hire mechanic for it.

Acceleration issue can point to many potential problem, from a tune-up to emission sensors.

2003 hummer If you have trouble in fixing your vehicles, try this link. Very helpful

Dear Gail, It is time to find out why you have an electrical problem, before it all gets worse. Please do not be surprised or discouraged when no one can find the problem. When you say "intermittent", you are right, but that makes it ever so hard for the mechanic to find, much less to fix. God bless your efforts. (Over the last 50 years, I have had to occasionally carry my own extra battery and jumper cables in the trunk of my car when no one could find the problem.)

Check if any mute function is not activated.

Wiring problem under the dash. Could be a ground issue as you said. You need to get under the dash and check the grounds.

Make sure the shift cable is properly moving the transmission into park.

A scan tool should be able to read the temp pids at operating temperature to see if they are "off" enough to cause problems . Check for fuel lines to close to heat sources as boiling of the fuel causing vapor lock may be happening after heat soaking .

The first thing should be to have it check for DTC'S - diagnostic trouble codes . Could have ignition switch problem , a shorted sensor bring down the class 2 data serial data network , the control modules all communicate on this data network . The starting system on this vehicle is controlled by the PCM - engine computer ! When you turn the key to start a voltage signal is sent to the PCM , if the PCM sees a voltage signal from the transmission range sensor and thier is no anti-theft system problems the PCM will energize the starter relay . 012 GM Class II Communications There is also a direct redundant class 2 serial data circuit between BCM and PCM. The following modules communicate on the class 2 serial data circuit: • splice pack - SP205 attaches to: • Air Suspension Module (ESC) • BCM • DDM • EBCM • FPDM • HVAC Control Module • IPC • PCM • Radio • TCSCM • splice pack - SP206 attaches to: • Audio Amplifier • RSA Control • VCIM • splice pack - SP207 attaches to MSM-Driver and SDM Hooking up a scan tool an checking scan data would be a first step . Testing electrical connections , B+ voltage at the fuse boxes ,main power feeds etc. Looking at wiring diagrams an power distribution diagrams . Using a voltmeter to test with. Electric Testing Techniques You Need to Know Free wiring diagrams here http://www.bbbind.com/free_tsb.html Enter vehicle info. year , make , model an engine ! Under system click power distribution then under subsystem click on power distribution . Click the search button then the blue link. Look at the power flow path an test with volt meter . Could be something simple but then again ! The complexity of the modern vehicle is well above most peoples scope .

large leak response normally means that the petrol cap has not been fitted correctly

check for faulty load leveler valves for the rear suspension the compressor should cut out when the pressure is attained and no suspension movement requires air

Any power source that is switched will work, so use a test light to find a fuse that is only powered when the key is turned to run.

well is that hummer that a 2 ton or 4 ton vehicle ? would take a lot of revs for first gear to make it roll from a standing start think it will be fitted with an 6 speed automatic transmission guessing only from my heavy vehicle driving experiences first should change below 3000 rpm if transmission was slipping in first gear you would know suggestion ring up the local hummer service division for the correct answer