How to Reset the Service Engine Light on Gmc Cars

by Contributing WriterUpdated June 12, 2017

Your Gmc car has an onboard diagnostic computer that will store trouble codes when there is something wrong with the vehicle's emissions control system. The emissions system is important and if it is malfunctioning, it can dramatically affect the performance of the Gmc car engine. Once you've fixed the vehicle, you need to know how to reset the check engine light. To do this, you need a special tool available at most auto parts stores called an OBD scan tool. The scan tool will have a feature that allows you to erase all stored engine codes, which will reset the check engine light.

Under The Hood:

 How to Reset the Service Engine Light on a GMC

Open the fuse panel by pulling down on the panel under the steering column with your fingers.

Pull the fuse for the electronic control unit, ECU, using the fuse pullers in the fuse panel. Use the fuse diagram on the underside of the fuse panel to locate the fuse for the ECU.

Turn the ignition on but don't crank the engine.

Wait five minutes before replacing the ECU fuse. The "service engine soon" light on the dash will blink and then shut off. This will reset the light.

 How to Reset the Check Engine Light on a GMC Envoy

Read the instruction manual for the OBD II DTC reader and eraser. There are many varieties that feature different options and have different methods for reading and erasing codes. While very easy to operate, the instruction manual will direct you how to properly use the reader.

Open the GMC Envoy's driver-side door and look under the dashboard to locate the OBD II connector.

Place the plug of the reader into the connector. Because of its shape, you can only plug it in one way.

Place the key in the ignition and turn the key two clicks forward to the accessory power position. This will illuminate the lights on the instrument panel without starting the engine of the Envoy.

Turn the power button on the reader (if equipped; most will turn on when the ignition key is turned to the "on" position).

Follow the steps from the instruction manual to read and erase the DTC(s). It is advisable to write the codes on a piece of paper.

Wait for the reader to tell you from the onscreen menu that the diagnostic trouble code has been erased, then unplug it from the connector.

Start the engine of the Envoy and look at the instrument panel to ensure the check-engine light is out.

Items you will need

  • OBD II DTC reader and eraser with instruction manual

 How to Reset the Check Engine Light of a 2006 GMC Envoy

Locate the open OBD port to the left of the fuse panel in the driver's side foot well.

Plug the OBD scan tool into the open port.

Turn the ignition to the "II" position (the "on" position), but do not try to crank the engine.

Press "erase" on the scan tool to erase all computer codes and reset the check engine light.

Items you will need

  • OBD scan tool

 How to Reset the "Service Engine Soon" Light on a 1998 GMC

Open the hood of the GMC and loosen the retaining nut on the negative battery cable clamp.

Slide the cable clamp off the negative battery terminal.

Wait 15 minutes, then reconnect the cable clamp.

Start the engine and run it for 5 to 10 minutes to allow your GMC vehicle to relearn its idle procedure.

Items you will need

  • Socket wrench

  • Socket set

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