2003 GMC Envoy

The 4.2L LL8 Atlas inline-6 engine develops severe timing chain stretch and guide failure. The primary and secondary timing chain guides crack, break apart, and send plastic debris into the oil pan. Symptoms include a loud rattling noise on startup that may persist, check engine lights with timing codes, and rough running. Complete guide disintegration can cause the chain to skip teeth, destroying the engine.

Replace all timing chains, tensioners, and guides as a complete set. This is a major repair requiring significant engine disassembly. Use updated GM guide parts with improved materials. Flush the oil pan and pickup tube screen to remove plastic debris. Maintain strict oil change intervals with quality synthetic oil to extend the life of the replacement parts.

The HVAC blend door actuators fail frequently on the GMT360 platform, producing a repetitive clicking or knocking noise from behind the dashboard. The actuator gears strip and the blend door gets stuck, causing the system to blow only hot or only cold air regardless of the temperature setting. The noise is particularly annoying as it occurs every time the ignition is turned on.

Replace the failed HVAC blend door actuator. The Envoy has multiple actuators controlling temperature, mode, and recirculation doors. The driver-side temperature actuator is the most common failure. Accessing the actuators requires partial dashboard disassembly. Use AC Delco replacement actuators for proper fit and function.

The Envoy is plagued by various electrical issues including intermittent gauge failures where the speedometer, tachometer, or fuel gauge stop working or read incorrectly. The instrument cluster stepper motors fail, causing the gauge needles to stick or read zero. Other electrical issues include power window failures, door lock malfunctions, and intermittent no-start conditions.

Replace or rebuild the instrument cluster. Cluster repair services are available that replace all stepper motors and re-solder the circuit board for $100-$200. For power window issues, replace the window regulator and motor assembly. For no-start conditions, inspect and clean the battery cables and ground connections, particularly the engine-to-chassis ground strap.

The engine cooling fan clutch fails, either locking up (causing excessive noise and drag) or freewheeling (causing overheating). A failed fan clutch that does not engage properly allows the engine to overheat in slow traffic and during towing. The 4.2L inline-6 runs hot under load, making a functioning fan clutch critical. Owners report overheating warnings during summer driving.

Replace the fan clutch assembly. A locked-up fan clutch will cause a loud roaring noise and reduced fuel economy. A freewheeling clutch will not cool adequately at idle or low speeds. Also inspect the radiator for clogging or corrosion, the thermostat for proper operation, and the coolant level and condition.

The front differential and transfer case develop fluid leaks from the output shaft seals, pinion seals, and case halves. Low fluid levels in either component can cause gear damage, bearing failure, and eventual loss of four-wheel drive function. Owners notice fluid spots under the front of the vehicle and may hear grinding or whining noises from the drivetrain when 4WD is engaged.

Replace the leaking seals and top off or replace the fluid in the front differential and transfer case. If the components have been run with low fluid, inspect the gears and bearings for damage. The transfer case encoder motor and front axle disconnect actuator should also be inspected, as they are common failure points on the GMT360 platform.

CERTAIN MAXZONE HEADLIGHT ASSEMBLIES, DEPO BRAND, P/NO 335-1120L-AS, SOLD FOR USE AS AFTERMARKET EQUIPMENT FOR THE ABOVE LISTED PASSENGER VEHICLES. DURING PRODUCTION THE LAMP HOUSING SHAPE DEFORMED DISTORTING THE ASSEMBLY ANGLE OF THE REFLECTOR AND INFLUENCED THE AIMING POSITION. THESE HEADLAMPS FAIL TO CONFORM TO THE REQUIREMENTS OF FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 108, LAMPS, REFLECTIVE DEVICES, AND ASSOCIATED EQUIPMENT.

DECREASED LIGHTING VISIBILITY MAY RESULT IN A VEHICLE CRASH.

MAXZONE WILL NOTIFY OWNERS AND OFFER REIMBURSEMENT FOR ANY NONCOMPLIANT HEADLIGHTS. THE RECALL BEGAN ON FEBRUARY 16, 2007. OWNERS MAY CONTACT MAXZONE AT 909-822-3288.

ON CERTAIN TRUCKS AND SPORT UTILITY VEHICLES, THE DRIVER WISHING TO SIGNAL A TURN BY MOVING THE DIRECTIONAL SIGNAL LEVER, (UP OR DOWN) MAY CAUSE THE FRONT MARKER/TURN LIGHTS AND REAR TURN LIGHTS TO FLASH IN A MANNER SIMILAR TO HAZARD WARNING, RATHER THAN FLASHING ON THE DESIRED SIDE ONLY.

THE DRIVER MAY NOT BE ABLE TO CLEARLY SIGNAL THEIR INTENTIONS TO TURN, CHANGE TRAVEL LANES, OR POTENTIALLY WARN OTHERS OF AN IMPAIRED VEHICLE OPERATING CONDITION INCREASING THE RISK OF A CRASH.

DEALERS WILL REPLACE THE SUSPECT FLASHER MODULES WITH A NEW FLASHER MODULE DESIGNED WITH SEALED RELAYS AND MORE DURABLE CONTACT MATERIAL INSIDE OF THE RELAYS FREE OF CHARGE. THE RECALL BEGAN ON AUGUST 4, 2005. ISUZU BEGAN MAILING OWNER LETTERS ON AUGUST 4, 2005. OWNERS MAY CONTACT CHEVROLET AT 1-800-630-2438, GMC AT 1-866-996-9463, ISUZU AT 1-800-255-6727, BUICK AT 1-866-608-8080, AND OLDSMOBILE AT 1-800-630-6537.

CERTAIN SPORT UTILITY VEHICLES HAVE WINDSHIELD WIPER SYSTEMS THAT WILL NOT TURN ON, CEASE OPERATION WHILE IN USE, FAIL TO TURN OFF/ON BY THEMSELVES (MOISTURE SENSITIVE WIPER SYSTEM), OR HAVE CONTINUOUS WINDSHIELD WASHER PUMP OPERATION BECAUSE THE PRESENCE OF WATER WITHIN THE WIPER MODULES CAN EITHER CAUSE A SHORT CIRCUIT OR CAN LEAD TO THE CORROSION OF COMPONENTS WITHIN THE MODULE.

DEPENDING ON THE OCCURRENCE AND WEATHER SITUATION, DRIVER VISIBILITY COULD BE REDUCED, WHICH COULD RESULT IN A CRASH.

DEALERS WILL COVER THE WINDSHIELD WIPER MODULE VENT HOLE WITH A PATCH. ALSO, THE WIPER MOTOR, CIRCUIT BOARD, AND ELECTRICAL CONNECTOR WILL BE INSPECTED TO SIGNS OF WATER INTRUSION AND/OR CORROSION AND BE REPLACED AS REQUIRED. THE RECALL BEGAN JULY 6, 2004. OWNERS SHOULD CONTACT CHEVROLET AT 1-800-630-2438; OLDSMOBILE AT 1-800-630-6537; OR GMC AT 1-866-996-9463.

CERTAIN MINIVANS, PASSENGER AND SPORT UTILITY VEHICLES FAIL TO COMPLY WITH THE REQUIREMENTS OF FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 225, "CHILD RESTRAINT ANCHORAGE SYSTEM." THE OWNER'S MANUAL DOES NOT EXPLAIN THE MEANING OF THE LOCATION SYMBOLS FOR THE CHILD RESTRAINT LOWER UNIVERSAL ANCHORAGE SYSTEM.

THIS DOES NOT MEET THE REQUIREMENTS OF THE STANDARD.

OWNERS WILL BE PROVIDED WITH A SUPPLEMENT FOR THEIR OWNER'S MANUAL. THIS SUPPLEMENT DESCRIBES AND SHOWS THE LOCATION SYMBOLS FOR THE CHILD RESTRAINT ANCHORS THAT ARE LOCATED IN THE VEHICLE AND ON THE CHILD RESTRAINT OR BOOSTER CUSHION. OWNER NOTIFICATION BEGAN AUGUST 18, 2003. OWNERS SHOULD CONTACT BUICK AT 1-866-608-8080, CADILLAC AT 1-866-982-2339, CHEVROLET AT 1-800-630-2438, GMC AT 1-866-996-9463, PONTIAC AT 1-800-620-7668, OR OLDSMOBILE AT 1-800-630-6537.

CERTAIN SPORT UTILITY VEHICLES WERE BUILT WITH A LEFT-FRONT BRAKE PIPE WITH A CIRCUMFERENTIAL SCORE AT A RANDOM LOCATION ALONG THE LENGTH OF THE PIPE AS THE RESULT OF THE MANUFACTURING PROCESS. IF THE BRAKE PIPE PARTIALLY OR FULLY FRACTURED, BRAKE PEDAL TRAVEL WOULD IMMEDIATELY INCREASE AND FRONT BRAKE PERFORMANCE WOULD BE REDUCED.

IF BRAKING PERFORMANCE IS REDUCED, A CRASH COULD OCCUR.

DEALERS WILL REPLACE THE LEFT-FRONT BRAKE PIPE. OWNER NOTIFICATION BEGAN ON MAY 29, 2003. OWNERS WHO TAKE THEIR VEHICLES TO AN AUTHORIZED DEALER ON AN AGREED UPON SERVICE DATE AND DO NOT RECEIVE THE FREE REMEDY WITHIN A REASONABLE TIME SHOULD CONTACT CHEVROLET AT 1-800-222-1020, GMC AT 1-800-462-8782, OR OLDSMOBILE AT 1-800-442-8006.

CERTAIN SPORT UTILITY VEHICLES FAIL TO COMPLY WITH THE REQUIREMENTS OF FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 114, "THEFT PROTECTION." THESE VEHICLES ARE EQUIPPED WITH A MECHANICAL OVERRIDE THAT COULD ALLOW THE IGNITION KEY TO BE REMOVED WITH THE SHIFT LEVER IN A POSITION OTHER THAN PARK. IN ADDITION, THESE VEHICLES HAVE AN OVERRIDE THAT CAN ALLOW THE TRANSMISSION TO BE SHIFTED OUT OF PARK WITH THE IGNITION IN THE OFF POSITION.

THESE OVERRIDES ARE NOT PERMITTED UNLESS THE VEHICLE HAS A LOCKING STEERING COLUMN.

DEALERS WILL ELIMINATE THESE CONDITIONS BY DISABLING THE OVERRIDES. OWNER NOTIFICATION BEGAN ON MAY 29, 2003. OWNERS WHO TAKE THEIR VEHICLES TO AN AUTHORIZED DEALER ON AN AGREED UPON SERVICE DATE AND DO NOT RECEIVE THE FREE REMEDY WITHIN A REASONABLE TIME SHOULD CONTACT CHEVROLET AT 1-800-222-1020, GMC AT 1-800-462-8782, OLDSMOBILE AT 1-800-442-6537, OR HUMMER AT 1-866-486-6376.

ON CERTAIN MINI VANS, PASSENGER AND SPORT UTILITY VEHICLES, SOME OF THESE VEHICLES HAVE A DRIVER'S SIDE AIR BAG THAT MAY NOT DEPLOY AS DESIGNED. IN ADDITION, THE AIR BAG INFLATOR COULD RUPTURE.

THIS COULD RESULT IN REDUCED CAPABILITY OF THE AIR BAG TO PROTECT THE DRIVER. ALSO IF THE AIR BAG INFLATOR RUPTURED, PIECES OF THE INFLATOR COULD STRIKE AND INJURE THE VEHICLE OCCUPANTS.

DEALERS WILL INSPECT, AND IF NECESSARY, INSTALL A NEW DRIVER'S AIR BAG. OWNER NOTIFICATION BEGAN ON MARCH 11, 2003. OWNERS WHO TAKE THEIR VEHICLES TO AN AUTHORIZED DEALER ON AN AGREED UPON SERVICE DATE AND DO NOT RECEIVE THE FREE REMEDY WITHIN A REASONABLE TIME SHOULD CONTACT BUICK AT 1-800-521-7300, CADILLAC AT 1-800-458-8006, CHEVROLET AT 1-800-222-1020, GMC AT 1-800-462-8782, OR PONTIAC AT 1-800-762-2737.

CERTAIN PASSENGER, MINI VANS, AND SPORT UTILITY VEHICLES HAVE AN AIR BAG INFLATOR ON THE DRIVER'S SIDE THAT COULD FRACTURE AT A WELD DURING A DEPLOYMENT.

PIECES OF THE INFLATOR COULD STRIKE AND INJURE VEHICLE OCCUPANTS AND THE AIR BAG CUSHION WOULD NOT INFLATE FULLY, REDUCING THE CAPABILITY OF THE BAG TO PROTECT THE DRIVER.

DEALERS WILL INSPECT, AND REPLACE, IF NECESSARY, THE AIR BAG MODULE ASSEMBLY ON THE DRIVER'S SIDE. OWNER NOTIFICATION BEGAN AUGUST 15, 2002. OWNERS WHO TAKE THEIR VEHICLES TO AN AUTHORIZED DEALER ON AN AGREED UPON SERVICE DATE AND DO NOT RECEIVE THE FREE REMEDY WITHIN A REASONABLE TIME SHOULD CONTACT BUICK AT 1-800-521-7300, CADILLAC AT 1-800-458-8006, CHEVROLET AT 1-800-222-1020, GMC AT 1-800-462-8782, OLDSMOBILE AT 1-800-442-6537, OR PONTIAC AT 1-800-762-2737.