Top 20 2008 GMC Envoy Denali Questions & Answers

Did you override the security system with security module if not you will have to do that it is a separate module that you will need

Not sure about some of the codes you have but looks like you may have traction control / stability control issues. The C code is a chassis code and they are really unusual. You may want to have those codes done again because my machine does not list body codes for some of those numbers. P codes yes, B codes no. But just a comment. If you ran this vehicle with all the wheels off the ground (on a lift) you will get every kind of weird code and light you can imagine. The traction control and stability control computers are very sensitive to issues that don't make sense to them. Running with all four wheels off the ground makes them really confused.

Under the drivers seat.

rough guess is that there is a connection that is not properly connected

Your problem is probably your actuator switch in the front differntial. it is an electronic switch and they sometimes stick or burn out .1A auto parts .com shows how to remove it on u tube . you remove an elector connector and than the switch un screws. sometimes easy but I have had to heat them with a torch to get them out. Go to google type in how to remove actuator switch chevrolet . it should bring up the video. I beleve this will solve your problem if this was helpful please leave good feed back

Turn signal switch or the bulb. Check both

well if they were replacesd not that long ago . take back to garage and see if they need to treak it a bit . sometimes they need adjusted or treaked a bit . you more than likly drove enough to have them seated but might be 1 or 2 lifters that just need that extra turn now . this is what it sounds like hopefully it is just this and not the crankshaft or pistons and bearings . . let me know how it goes .

I am guessing it is still under the factory warranty. Take it to the dealership and have them fix it for free.

look goto autozone they have a all in connector for towing so much me easer about 40 dollars you go back to driver side rear harnes when you unplug it the pig tail joins all connectors to geather along with your traller pig tail no mus no fus

Google your question. About 280,000 results (0.61 seconds) https://www.autozone.com/repairguides/S-T-Series-Blazer-Bravada-Envoy-Jimmy-Rainier-Trailblazer-Xtreme/Component-Locations/Secondary-Air-Injection-AIR-Pump-Relays/_/P-0996b43f80cb36eb

Picture would be perfect.

Your drive train may be in limp mode, which indicates something seriously wrong with it (engine or transmission). Check for trouble codes with a code reader.

located in the back . It's called the LGM fuse #2 (Lift Gate Module) The Lift Gate Module controls the defroster grid circuit.

Look for black wire. Check it by using an omh meter and testing it to a ground.

Have you checked the fusible links running off the starter connection at the starter?

Check youtube for video

I'm pretty sure that there is a video on you tube on how to reset GM speedometers. Give it a shot.

threw a po128 ??? Doesn't throw code's ,it stores code's . P0128 code does not tell you to replace the sensor either . With every code comes a diagnostic test procedure listed in a factory info. manual . DTC P0128: Engine Coolant Temperature (ECT) Below Thermostat Regulating Temperature The purpose of this diagnostic is to analyze the performance of the thermostat, by using the ECT sensor to determine if the engine coolant will increase at the correct rate, and also meet the calibrated target temperatures under various operating conditions. The ECM uses the start-up ECT and the start-up intake air temperature (IAT) to begin the diagnostic calculation. The air flow into the engine is accumulated, and vehicle speed, distance, and engine run time are also factored in to determine if the ECT does increase normally and reach the calibrated target temperatures. Diagnostic Aids ?€¢ DTC P0128 occurring with insufficient vehicle interior heating is an indication of improper thermostat operation.

?€¢ Corrosion in the ECT sensor terminals or the ECT harness connector results in a greater voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a colder ECT.

?€¢ A slight to moderate resistance in the ECT sensor signal circuit or low reference circuit will affect this diagnostic. This condition results in a greater voltage on the ECT sensor signal circuit, which is interpreted by the ECM as a colder ECT.

Circuit/System Verification

1. Ignition OFF, inspect the cooling system surge tank for the proper coolant level. Refer to Cooling System Leak Testing and Cooling System Draining and Filling .
2. Ignition OFF for 8 hours or greater.
3. Ignition ON, observe the scan tool ECT Sensor and IAT Sensor parameters. The ECT, IAT and ambient temperatures should be within 15?°C (27?°F) of each other.
Important: A critical analysis of the operation of the thermostat is necessary to properly diagnose this DTC.
4. Verify the proper heat range, and the operation of the thermostat. Refer to Thermostat Diagnosis .
5. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the ECT sensor.
2. Ignition OFF for 90 seconds, test for less than 5 ohms between the low reference circuit terminal B and ground.
?‡' If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, verify the scan tool ECT Sensor parameter is colder than -39?°C (-38?°F).
?‡' If warmer than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the ECM.
4. Install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool ECT Sensor parameter is warmer than 149?°C (300?°F).
?‡' If colder than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
5. If the circuits test normal, test or replace the ECT sensor.

Check that brake switch has not become displaced or somehow loose. Its likely the switch is failing and needs replaced.

Get underneath, locate the starter, there should be a positive wire that leads back to the battery. Uncapp it connect your positive external source to it, then negative to the body..this should allow you to unlock the doors and by extension your bonnet....all the best..