GMC Answered Questions & Fixed Issues

wow no year car told. now that is a Hard row to hoe.. 2007 to NOW. no engine told and cats are designed for engine and smog ,in one countries laws. reset the all DTC errors via button on scan tool; then drive see if P0420 comes back, first not buy $400 cat on a whim./ I roll the dice, see 10, 2010 and answer. and LY7 engine V6 (there are others) DTC P0420: Catalyst System Low Efficiency Bank 1 DTC P0430: Catalyst System Low Efficiency Bank 2 bank 1 means , that bank that contains cylinder #1 where is cylinder #1 it on all V engines, that cylinder that is MOST forward. all cyl 1 are offset front never post about cars and no year or engine told or post #8th digit of VIN this is engine code, so answer and be correct. (USA answer me only)

Have you looked over there?

If it has a distributor you will want to make sure that it is in time. If the ECU cant find the cam signal it doesn't know when to fire the coil. I have ran into this more tha once on that year truck.

no year car told, no engine told and is a pure engine/EFI question. a minute not 10second and dies, the dash IMMO lamp must not be unhappy or the engine is immoblizeds in 1 to 10 seconds. most cars or dead totally others. well , there are 50 causes or stalls on all engines we do up to 20 test using 10 or more tools to find real cause. guessing 50 times , no shop does that . can take the line and put in a can of gas it will run????????? HUH? this means test fuel works? sprayed into the intake and runs means it runs for 3seconds on test fueL and stalls/ we cant see your acts there, Impossible. too. here is the order (pure physics Otto cycle gas engine) ASE rules( books/training) engine must be good. (compressing tests pass and test fuel works.) spark must be good. if is test fuel works and and runs for 3 second is all a good sign then last is fuel all above ok testing fuel pressure must be at spec, no car told SO can not look that up. sierra what is it and year. Chevrolet C/K C1500 pickup or k = 4wd or ) what engine, lots of engine, Chevrolet Silverado Chevrolet Suburban top fix any car engine learn what is under hood first the RPO codes tell that. and VIN . by year

My guess would be something inside the transfer case.

Question edited for clarity. Question moved to model category. https://www.google.com/search?q=2019+GMC+Savana+FSCM+Diagram Fusebox information https://www.google.com/search?q=2019+gmc+savana+fusebox+wiring+diagram ECM https://www.google.com/search?q=2019+gmc+savana+ECM+wiring+diagram ..

In the engine compartment fuse box, it's the one labeled LIGHTING

Is the check engine light on, or yellow wrench light symbol? Hook up a professional grade scan tool an check for DTC'S - diagnostic trouble codes . No throttle response , problem with electric throttle control . Two position sensors in gas pedal assembly - two position sensors in the electronic throttle body - plus a DC motor to control throttle plate position. Other poster has no clue. Dirty throttle body would not cause no throttle response, rough or unstable idle for sure. If this answer helps you, please donate whatever you can. Thank you! paypal.me/TesfayHaile rip-off

I would look for harness damage under the bed since the brake and tails are seperate circuits.

Q1: REVERSE IS DEAD TOO?> no VIN told or if transmission is automatic. or manual no engine told of 3 and tranny size matches engine power 4L60-e transmission is on 5.0L gm engine. I think most Envoy are A/T boxes. USA, shows this . PRNDL. Reverse. Drive and Low fail? say those words is east,. the transmission needs service, vast problems possible they are complex. causes, top:(SCAN THE PCM IS WISE SEE IF IT SEES A HUGE PROBLEM THERE.) BUT REVERSE DEAD IS A VERY BAD SIGN. SCAN THE PCM FOR SOLENOID ERRORS!

1. ATF oil leaked out of box and now dry, diP stick it? ATF smells burnt or looks like TAG is bad news. or metal flakes in the ATF DRIPPED TO A SHEET OF PAPER.
2. fuses blown but most time reverse still works.!!!
3. transmission shift linkage failed. (the service manual covers the steps to check that, Read the SM?)
4. transmission shift solenoids bad. (reverse? has none)
5. transmission is bad. (means removal time)

NOW IF REVERSE FAILS ALL THESE THINGS HAPPEN TO ATTAIN IT. you asked so here is a complex answer, (not all) AND LOTS MORE TO FAIL. http://67-72chevytrucks.com/vboard/showthread.php?t=447470

1st step torque 22ft lb, 2nd step tighten an additional 155 degrees per haynes manual sequence.

hot or cold engine High and how high is RPM not told. no it is not evap failing to cause RPM failures. 2 problems sure, but not THE problem well gas cap loose or bad is first. simple fix that is costs nothing, and cap good or cap bad $10 fix.but not RPM off. then purge solenoid. RPM high is the best clue here. for sure mine fails every 50k miles it seems and pull the valve and flex the valve inside while spraying silicon oil spray inside it and it goes 50k more miles costing me 50 cents lube. 497 Evaporative Emission (EVAP) System No Flow During Purge the test in the service manual are extensive example

• A loose, missing, or damaged fuel fill cap can cause this DTC to set.
• A stuck closed, blocked, or restricted EVAP canister purge solenoid valve, can cause this DTC to set.
• A blockage or restriction in the EVAP canister purge solenoid valve vacuum supply hose, EVAP canister purge solenoid valve purge pipe, EVAP canister, or vapor pipe, can cause this DTC to set.
• A temporary blockage in the EVAP canister purge solenoid valve, purge pipe or EVAP canister could cause an intermittent condition. Inspect and repair any restriction in the EVAP system.
• To help locate intermittent leaks, use the J 41413-200 Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light. Introducing smoke in 15 second intervals will allow less pressure into the EVAP system. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
• To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT .
• Observe the Freeze Frame/Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set. This may assist in diagnosing the condition.

the valve is here "P" #10 if it leaks running, stuck open rpm can go wild or the hose to it is cracked

well the harness there in most cars/trucks are sold new with 5 to 10 radios. and are not the same harnesses. or read the service manual https://eautorepair.net/Marketing/Default.asp

anon turn off the key (wrong) or turn off the wiper switch (good0 or both, not told.' here it is, as you can see , it all loses power key off, as in ALL DEAD. BUT IF YOU TURN just THE WIPER TO OFF. AT ITS SWITCH IT MUST TURN OFF. AND AUTO PARK (switch not bad) THAT MAGIC HAPPENS BY THE YELLOW WIRE BELOW RIGHT SIDE. so yellow wire busted.(mice eat it, IDK) or wiper guts bad( the internal so called PULSE board) marked control logic below. THIS MODULE IS SOLD HERE. https://www.rockauto.com/en/catalog/gmc,2002,sierra+1500,6.0l+v8,3300378,wiper+&+washer,wiper+motor+module,17720

check for jumped timing --

Question edited for clarity. Question moved to model category. The first obvious thing to do it check for lights left on, dome light, hood and trunk lights. This is how you test for what is causing the parasitic drain. https://www.fixya.com/cars/r29903527-parasitic_draw_car_batteries ..

Question edited for clarity. Question moved to model category. General information and videos https://studentlesson.com/airbag-sensors-functions-symptoms-location-testing/

There are 6 varieties of Sierra and hundreds on factory connector plugs on each one. Here are a few https://www.google.com/search?q=2010+GMC+Sierra.+What+are+the+colors+on+my+factory+plug and videos of items with plugs and colors ..

What year motor Does it have a distributer or what

Info in the link and in general in the videos https://www.google.com/search?q=1991+GMC+Safari.+compression+test