SPECIAL POLICY ADJ. - LINEAR EXHAUST GAS RECIRCULATION SYS.. GMC Truck GMC Suburban

SUBJECT: 96067(A) - SPECIAL POLICY ADJUSTMENT - LINEAR EXHAUST GAS RECIRCULATION SYSTEM

MODELS: 1992-94 S/T, MIL, AND 1993-94 C TRUCKS EQUIPPED WITH 4.3L ENGINE (L35 OR LB4) AND LINEAR EXHAUST GAS RECIRCULATION VALVE (LEGR)

THIS BULLETIN CANCELS AND REPLACES SPECIAL POLICY BULLETIN 96067 ISSUED FEBRUARY, 1997.

THE SPECIAL POLICY HAS BEEN EXTENDED TO COVER 1992 S/T AND M/L TRUCKS EQUIPPED WITH 4.3L (135) ENGINE. THIS REVISION ALSO CONTAINS CHANGES IN THE "SERVICE PROCEDURE" TO CLARIFY THAT ANY ADDITIONAL NECESSARY DIAGNOSIS AND REPAIRS, THAT ARE NOT RELATED TO THE LEGR CONDITION, ARE NOT COVERED BY THE SPECIAL POLICY. THE CUSTOMER SHOULD BE INFORMED THAT ANY FURTHER SERVICE THAT IS NOT COVERED BY NEW VEHICLE WARRANTY WILL NOT BE COVERED BY THIS POLICY. ALSO, THE "CLAIM INFORMATION" SECTION IS REVISED TO ADD LABOUR OPERATION T-2209 FOR PERFORMING A SYSTEM CHECK WHEN DETERMINING THAT THE LEGR SYSTEM IS NOT INVOLVED WITH A CUSTOMER COMPLAINT. THE CUSTOMER SHOULD NOT BE CHARGED FOR THIS SYSTEM CHECK.

This Special Policy Adjustment applies only to those vehicles that are equipped with Linear Exhaust Gas Recirculation Valves. Some vehicle lines equipped with 4.3L engines in a given model year were built with and without Linear Exhaust Gas Recirculation Valves due to the emission control requirements of various combinations. There are too many variables to describe in this bulletin. THE ONLY SURE METHOD TO DETERMINE IF A CERTAIN VEHICLE IS INVOLVED IS TO ACCESS THE VEHICLE SERVICE INFORMATION SCREEN ON DCS. THE VEHICLE WILL BE IDENTIFIED WITH A NOTE "REFER TO SPECIAL POLICY 96067- LINEAR EXHAUST GAS RECIRCULATION SYSTEM" AS WELL AS THE STANDARD WARRANTY VERBIAGE.

CONDITION

Some customers of 1992-94 model year S/T, M/L and 1993-94 model year C trucks may experience Linear EGR valve sticking, or foreign material holding the valve open/closed This will cause a DTC 32 to be set which may be accompanied by poor driveability conditions such as engine surge, engine knock, engine stall, rough idle, and/or hard starting.

CAUSE

Carbon deposits or foreign material affecting Linear EGR operation.

SPECIAL POLICY ADJUSTMENT

This special policy covers the condition described above for a period of seven years or 120,000 km (75,000 miles), whichever occurs first, from the date the vehicle was originally placed in service, regardless of ownership.

The repairs will be made at no charge to the owner. This special policy applies ONLY to repairs requiring Linear EGR system servicing.

VEHICLES INVOLVED

Involved are certain 1992 - 1994 S/T, MAL, and 1993 - 1994 C trucks equipped with 4.3L engines built within the following VIN breakpoints:.

YEAR DIVISION MODEL PLANT PLANT FROM THROUGH CODE

1992 Chevrolet M/L Baltimore "B" NB100005 NB234001 1992 Chevrolet S/T Pontiac West "0" N0100005 N0164189 1992 Chevrolet S/T Moraine "2" N2100046 N2226380 1992 Chevrolet S/T Shreveport "8" N8100006 N8100012 1993 Chevrolet M/L Baltimore "B" PB100001 PB225266 1993 Chevrolet S/T Pontiac West "0" P0100002 P0196990 1993 Chevrolet S/T Moraine "2" P2100001 P2218436 1993 Chevrolet S/T Shreveport "8" P8100003 P8100009 1993 Chevrolet C Fort Wayne "Z" PZ100018 PZ259079 1993 Chevrolet C Pontiac East "E" PE100006 PE254274 1994 Chevrolet M/L Baltimore "B" RB100000 RB248996 1994 Chevrolet S/T Pontiac West "0" R0100001 R0184858 1994 Chevrolet S/T Moraine "2" R2100001 R2179415 1994 Chevrolet S/T Shreveport "8" R8100009 R8242802 1994 Chevrolet S/T Linden "K" RK100003 RK183995 1994 Chevrolet C Fort Wayne "Z" RZ100013 RZ288038 1992 GMC M/L Baltimore "B" NB500005 NB551338 1992 GMC S/T Pontiac West "0" N0500004 N0820806 1992 GMC S/T Moraine "2" N2500002 N2539169 1992 GMC S/T Shreveport "8" N8515462 N8529232 1993 GMC M/L Baltimore "B" PB500002 PB552969 1993 GMC S/T Pontiac West "0" P0500002 P0528018 1993 GMC S/T Moraine "2" P2500005 P2543251 1993 GMC S/T Shreveport "S" P8500001 P8524622 1993 GMC C Fort Wayne "Z" PZ505129 PZ552871 1993 GMC C Pontiac East "E" PE506261 PE565548 1994 GMC M/L Baltimore "B" RB500000 RB558700 1994 GMC S/T Pontiac West "0" R0500001 R0535325 1994 GMC S/T Moraine "2" R2500001 R2527917 1994 GMC S/T Shreveport "8" R8500040 R8533970 1994 GMC S/T Linden "K" RKS00002 RK525999 1994 GMC C Fort Wayne "Z" RZ500200 RZ572002 1992 Oldsmobile T Moraine "2" N2700001 N2711870 1993 Oldsmobile T Moraine "2" P2700001 P2709695 1994 Oldsmobile T Moraine "2" R2700001 R2707710 1994 Oldsmobile T Pontiac West "0" R0700001 R0709971

NOTICE: Dealers should confirm vehicle eligibility through DCS on the Vehicle Owner Name and Address Warranty Coverage screen.

PARTS INFORMATION

1992 L35 (4.3L) WITH LINEAR EGR VALVES ONLY

Body Style Usage New Memcal New Broadcast Code New PROM I.D. Part Number (PROM Label) (Scan Tool)

M-Van L35 16255717 CBJU 5721 & NA5/NA6

M-Van L35 16255723 CBJX 5741 & NB2

L-Van L35 16255719 CBJW 5731 & NA5/NA6

L-Van L35 16255726 CBJY 5751 & NB2

S/T Utility L35 & 16255728 CBJZ 5761 & T Pickup NA5/NA6/NB2 Utility

S Pickup L35 16255728 CBJZ 5761 & NA5/NA6

S Pickup L35 16211730 CBKA 5771 & NB2

1993 LB4/L35 (4.3L) WITH LINEAR EGR VALVES ONLY

Body Style Usage Axle New Memcal New Broadcast New PROM I.D. Part Number Code (PROM (Scan Tool) Label)

C-Pickup LB4 GU4 (3.08) 16239290 BUZA 9271 & NRQ GU6 (3.42)

M-Van L35 GU6 (3.42) 16239362 BUZJ 9331 & NA5/NA6 GT4 (3.73)

M-Van L35 GU6 (3.42) 16239338 BUZF 9311 & NB2 GT4 (3.73)

M-Van LB4 GU5 (3.23) 16239394 BUZP 9285 & NB2 GU6 (3.42)

M-Van LB4 GT4 (3.73) 16239379 BUZN 9275 & NB2

L-Van L35 GU6 (3.42) 16239347 BUZH 9321 & NA5/NA6 GT4 (3.73)

L-Van L35 & NB2 GU6 (3.42) 16239323 BUZD 9301 GT4 (3.73)

S/T Pickup L35 GU4 (3.08) 16239400 BUZM 9361 & S/T & NA5/NA6 GU6 (3.42) Utility GT4 (3.73)

T Pickup L35 GU4 (3.08) 16239376 BUZK 9341 & S/T & NB2 GU6 (3.42) Utility GT4 (3.73)

S-Pickup L35 GU4 (3.08) 16239397 BUZL 9351 & NB2 GU6 (3.42)

PARTS INFORMATION (CONT'D.)

1994 LB4/L35 (4.3L) WITH LINEAR EGR VALVES ONLY

Body Style Usage Axle New Memcal New Broadcast New PROM I.D. Part Number Code (PROM (Scan Tool) Label)

C-Pickup LB4 GU4 (3.08) 16239432 BWAB 9385 & NB6 GU6 (3.42)

M-Van L35 GU6 (3.42) 16239423 BUZY 9355 & NA5/NA6 GT4 (3.73)

M-Van L35 GU6 (3.42) 16239408 BUZT 9315 & NB6 GT4 (3.73)

M-Van LB4 GU5 (3.23) 16239429 BWAA 9375 GU6 (3.42)

M-Van LB4 GT4 (3.73) 16239427 BUZZ 9365

L-Van L35 GU6 (3.42) 16239410 BUZU 9325 & NA5/NA6 GT4 (3.73)

L-Van L35 GU6 (3.42) 16239412 BUZW 9335 & NB6 GT4 (3.73)

T-Pickup LB4 GU4 (3.08) 16204006 BKZN 4015 & M30 & NB6 GU6 (3.42) GT4 (3.73)

S/T-Pickup L35 GU4 (3.08) 16239406 BUZS 9305 GU6 (3.42) GT4 (3.73)

S/T-Utility L35 GU4 (3.08) 16239420 BUZX 9345 (Except CTF) GU6 (3.42) GT4 (3.73)

S/T-Utility L35 GU6 (3.42) 16239403 BUZR 9295 & CTF GT4 (3.73)

Due to the low number of vehicles involved and the limited availability of these parts, dealers should not order the following part numbers for use as shelf stock.

16239338 16239394 16239379 16239323 16239376 16239397

16239432 16239408 16239427 16239412 16204006 16255717

16255723 16255719 16255726 16255730

CUSTOMER NOTIFICATION

Customers of 1992 model year vehicles will be notified of the Special Policy by General Motors of Canada Limited. Customers of 1993-1994 vehicles were notified in February 1997. (See copies of customer letters included with this bulletin.)

CUSTOMER REIMBURSEMENT

Customer claims for reimbursement on previously paid repairs to clean or replace the EGR valve are to be submitted by February 28, 1998. Repairs must have occurred within seven years of the date the vehicle was originally placed in service, or 120,000 km, whichever occurs first. Owners must submit original documentation which reasonably confirms the amount of unreimbursed repair expense(s), a description of the repair, date of the repair, and the person or entity performing the repair. Claims for customer reimbursement of previously paid repairs are to be submitted as a Net Item Dollar Amount following instructions under Claim Information.

If the work was done by someone other than a GM dealership the amount of reimbursement may be limited to the amount the repair would have cost GM to have it completed by a GM dealership. Dealers must receive paid receipts or invoices verifying the repair, the amount charged, proof of payment, and the date of payment of those charges by February 28, 1998.

SERVICE PROCEDURE

System Check: Check for Diagnostic Test Code (DTC) 32 with Tech I or Tech II. If DTC 32 is not present, perform LEGR Debris Purge and Function Test (listed below) to verify normal operation of the LEGR Valve. If the LEGR system is operating properly, inform the customer that their vehicle does not have the condition listed in the owner letter. If poor driveability conditions persist, inform the customer that any further diagnosis and repairs will be at their expense if vehicle is outside the parameters of the new vehicle warranty.

Correction: If DTC is present, WMI new Memcal from the PARTS INFORMATION tables listed in this bulletin. After installing the new Memcal, perform the LEGR Debris Purge and Function Check listed below.

LEGR Debris Purge and Function Check: Using a Tech I or Tech II, with transmission in park, and parking brake applied, and with engine at 1,500 RPM, command the LEGR valve to 100% position. Then command the LEGR valve to 0% position while monitoring actual and desired LEGR position. This procedure is intended to clear any foreign material from the valve.

Did the LEGR valve desired position agree with the actual position? If yes, the LEGR valve is functioning normally. If not, repeat the debris purge test. If the desired and actual valve positions still do not agree, refer to DTC 32 section of the Driveability and Emissions manual.

Vehicle (LEGR) Road Test: If the engine is operating normally after the Memcal replacement and/or LEGR valve replacement (if necessary after referring to DTC 32 section of the Driveability and Emissions manual), a road test should be performed. During vehicle road test, after installing the new Memcal, the technician may notice increased LEGR valve activity during light throttle maneuvers. This increased activity is due to the LEGR valve stroking during which time the actual position will momentarily exceed the desired position. This is normal LEGR function with this calibration. Road test the vehicle for reported driveability concerns and verify LEGR function. Have any noted problems been corrected? If yes, system is OK: return vehicle to customer. If not, refer to appropriate section of the Driveability and Emissions manual.

CLAIM INFORMATION

Submit a Product Campaign Claim with the information indicated below:

Complaint Failure Code Code Repair Performed Parts Labour 0p Labour Hours Allow

System Check - No LEGR System Repair PV 95 Needed 1) C-Truck T-2209 0.3 HRS 2) S/T Truck/Utility 0.3 HRS 3) M/L Van 0.3 HRS

Install New PROM PV 95 1) C-Truck T-2210 0.6 HRS 2) S/T Truck/Utility 0.6 HRS 3) M/L Van 0.6 HRS

Install New LEGR Valve PV 95 1) C-Truck T-2211 0.3 BRS 2) S/T Truck/Utility 0.3 BRS 3) M/L Van 4.3L (L35) 0.3 HRS 4) KVL Van 4.3L (LB4) 0.4 HRS

Reimbursement for T-2212 0.2 hr previous repairs to Administrative PV 95 the Linear EGR system Labour Allowance

* The "Parts Allowance" should be the sum total of the current GMSPO Dealer Net price plus 30% (for 1992 and 1993 vehicles) or 40% (for 1994 vehicles) for parts required to complete the repair.

February 1997

Dear General Motors Customer:

As the owner of a 1993 or 1994 S/T, M/L or C truck equipped with a 4.3L engine, your satisfaction with our product is of utmost concern to us. Your vehicle was provided with a new vehicle warranty which covers certain parts of your vehicle for a specified period. These warranties are of considerable value to you if you should experience problems with your vehicle.

This letter is intended to make you aware that some 1993 and 1994 S/T, M/L and C truck models equipped with 4.3L engines may experience a condition where the Linear Exhaust Gas Recirculation (LEGR) valve sticks, or foreign material holds the valve open or closed. This will cause a Malfunction Indicator Light illumination ("Service Engine Soon"), which may be accompanied by poor driveability such as engine surge, engine knock, engine stall, rough idle, and/or hard starting. A vehicle with this condition may be more likely to fail province mandated emission tests.

General Motors of Canada Limited is therefore taking the following action. We are providing owners with special warranty coverage. If the above mentioned condition occurs within seven (7) years of the date your vehicle was originally placed in service or 120,000 km (75,000 miles), whichever occurs first, the condition will be repaired for you at no charge.

This is not a recall campaign. Do not take your vehicle to your GM dealer as a result of this letter unless you believe that your vehicle has the condition as described above. Keep this letter with your other important glovebox literature for future reference.

If you have already paid for some or all of the cost to have your LEGR valve cleaned or replaced and your in-service time and mileage was less than seven (7) years and 120,000 km (75,000 miles), you may wish to contact your GM dealer to seek reimbursement. You may be eligible for partial or complete reimbursement of costs if genuine GM parts were used in the repair. If the work was done by someone other than a GM dealership the amount of reimbursement may be limited to the amount the repair would have cost GM to have it completed by a GM dealership. Please provide your dealer with your original paid receipts or invoices verifying the repair, the amount charged, proof of payment, and the date of payment of those charges by February 28, 1998.

Repairs and adjustments qualifying under this special coverage must be performed by a General Motors dealer.

If parts are required, ask your dealer for details regarding their availability. If parts are not in stock, they can be ordered before scheduling your service date.

We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products.

Customer Support Department General Motors of Canada Limited 96067

July 1997

Dear General Motors Customer:

As the owner of a 1992 S/T or NM truck equipped with a 4.3L engine, your satisfaction with our product is of utmost concern to us. Your vehicle was provided with a new vehicle warranty which covers certain parts of your vehicle for a specified period. These warranties are of considerable value to you if you should experience problems with your vehicle.

This letter is intended to make you aware that some 1992 S/T and M/L truck models equipped with 4.3L engines may experience a condition where the Linear Exhaust Gas Recirculation (LEGR) valve sticks, or foreign material holds the valve open or closed. This will cause a Malfunction Indicator Light illumination ("Service Engine Soon"), which may be accompanied by poor driveability such as engine surge, engine knock, engine stall, rough idle, and/or hard starting. A vehicle with this condition may be more likely to fail province mandated emission tests.

General Motors of Canada Limited is therefore taking the following action. We are providing owners with special warranty coverage. If the above mentioned LEGR condition occurs within seven (7) years of the date your vehicle was originally placed in service or 120,000 km, whichever occurs first, the condition will be repaired for you at no charge. Other conditions that may cause similar or different driveability complaints, or cause a Malfunction Indicator Light illumination, that are not a result of the LEGR condition, are not covered by this special warranty coverage. Any repairs that would be necessary due to other conditions would be, your responsibility, if you elect to have your dealer provide the service.

If you have already paid for some or all of the cost to have your LEGR valve cleaned or replaced and your in-service time and mileage was less than seven (7) years and 120,000 km, you may wish to contact your GM dealer to seek reimbursement. You may be eligible for partial or complete reimbursement of costs if genuine GM parts were used in the repair. If the work was done by someone other than a GM dealership the amount of reimbursement may be limited to the amount the repair would have cost GM to have it completed by a GM dewership. Please provide your dealer with your original paid receipts or invoices verifying the repair, the amount charged, proof of payment, and the date of payment of those charges by February 28, 1998.

Repairs and adjustments qualifying under this special coverage must be performed by a General Motors dealer.

If parts are required, ask your dealer for details regarding their availability. If parts are not in stock, they can be ordered before scheduling your service date.

We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products.

Customer Support Department General Motors of Canada Limited 96067A

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.