SPECIAL POLICY ADJ. - LINEAR EXHAUST GAS RECIRCULATION SYS.. Chevrolet S10 Pickup

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

MODELS: 1992-94 S/T,M/L,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 (L35) 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. ALSO, THE "CLAIM INFORMATION" SECTION IS REVISED TO ADD LABOR 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 requirments 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 interrogate VISS (under the heading VEHICLE WARRANTIES) or GMC ServiceNet (referring to the VEHICLE WARRANTY COVERAGE) to see if this special policy applies. Both VISS and GMC ServiceNet will display the following message for involved vehicles - "LINEAR EGR VALVE SPCL POLICY #96067".

CONDITION

Some customers of 1992-94 model year S/T, M/L and 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 75,000 miles (120,000 km), 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 1993 and 1994 S/T, M/L and C trucks equipped with 4.3L engines built within the following VIN breakpoints:

PLANT YEAR DIVISION MODEL PLANT CODE FROM THROUGH ---- --------- ----- ------------ ----- -------- -------- 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 "8" 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" RK500002 RK525999 1994 GMC C Fort Wayne "Z" RZ500200 RZ572002 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 VISS (Vehicle Information Service System) or ServiceNet (GMC only) prior to beginning repairs covered by this policy. [Not all vehicles within the above breakpoints may be involved]

PARTS INFORMATION

1992 L35 (4.3L) WITH LINEAR EGR VALVES ONLY

Body Usage New Memcal New Broadcast New PROM I.D. Style Part Number Code (Scan Tool) (PROM Label) ----- --------- ---------- ------------- ------------ 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/Utility NA5/NA6

S Pickup L35 16255728 CBJZ 5761 & NA5/NA6

S Pickup L35 16255730 CBKA 5771 & NB2

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

Body Usage Axle New Memcal New Broadcast New PROM I.D. Style Part Number Code (Scan Tool) (PROM 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 GU6 (3.42) 16239323 BUZD 9301 & NB2 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 GT6 (3.42)

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 (Scan Tool) (PROM 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 GU4 (3.73)

M-Van L35 GU6 (3.42) 16239408 BUZT 9315 & NB6 GU4 (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 will be notified of this special policy on their vehicles by General Motors (see copy of divisional customer letter(s) for 1992 model year vehicles included with this bulletin - new customer letters will not be sent for 1993 and 1994 model year vehicles).

CUSTOMER REIMBURSEMENT

Customer claims for reimbursement on previously paid repairs to service the LEGR system are to be submitted by March 1, 1998 (this time limitation may be longer depending on the law in some states, such as California, Connecticut, Virginia, and Wisconsin). Repairs must have occurred within seven years of the date the vehicle was originally placed in service, or 75,000 miles (120,000 km), whichever occurs first. Owners (and/or prior 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. CUSTOMERS FROM THE STATES OF CALIFORNIA, CONNECTICUT, VIRGINIA, AND WISCONSIN MUST SUBMIT REQUESTS FOR REIMBURSEMENT DIRECTLY TO (CHEVROLET/GMC/OLDSMOBILE) PER INSTRUCTIONS IN THE OWNER LETTER.

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, install 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 11, with transmission in park, and parking brake applied. 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 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

For vehicles repaired under warranty, submit a claim with the information indicated below: * Complaint Failure Parts Labor Code Code Repair Performed Allow Op Labor Hours --------- ------- ---------------------- ----- ----- ----------- System Check - No LEGR System Repair Needed PV 95 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

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

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

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

REIMBURSEMENT

Customer requests for reimbursement of previously paid repairs to correct the Linear Exhaust Gas Recirculation system are to be submitted prior to or by March 1, 1998 (this time limitation may be longer depending upon the law in your state).

When a customer requests reimbursement, they must provide the following:

- Proof of ownership at time of repair.

- Original paid receipt confirming the amount of unreimbursed repair expense(s), a description of the repair, and the person or entity performing the repair.

Claims for customer reimbursement on previously paid repairs are to be submitted as required by WINS.

NOTICE: Refer to the appropriate divisional service policies and procedures manual, section 1.6.1, for specific procedures regarding customer reimbursement verification.>

June, 1997

Dear <Division(s)> Customer:

As the owner of a 1992, 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.

Condition:

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This letter is intended to make you aware that some 1992, 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 state mandated emission tests.

Action:

-------

General Motors 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 75,000 miles (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.

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.

Reimbursement:

--------------

(Statement for all states except as shown below.)

If you have already paid for some or all of the cost to have your LEGR system repaired and your in service time and mileage was less than seven (7) years and 75,000 miles (120,000 km), you should contact your dealer to seek reimbursement. Please provide your retailer with your original paid receipts or invoices verifying the repair, the amount charged, proof of payment, the date of payment of those charges and proof of ownership of the vehicle at the time of the repair by March 1, 1998.

(Statement for California, Connecticut, Virginia and Wisconsin)

If you have already paid for some or all of the cost to have your LEGR system repaired and your in service time and mileage was less than seven (7) years and 75,000 miles (120,000 km), you should write (DIVISIONAL SPECIFIC ADDRESS) to seek reimbursement. Please provide your original paid receipts or invoices verifying the repair, the amount charged, proof of payment, the date of payment of those charges and proof of ownership of the vehicle at the time of the repair by March 1, 1998.

(Statement for California, Connecticut, Virginia and Wisconsin)

If you have already paid for some or all of the cost to have your LEGR system repaired and your in service time and mileage was less than seven (7) years and 75,000 miles (120,000 km), you should write (DIVISIONAL SPECIFIC ADDRESS) to seek reimbursement. Please provide your original paid receipts or invoices verifying the repair, the amount charged, proof of payment, the time of the repair This information must be provided within two (2) years after the date on which you paid for the repair.

Contacting Your Dealer:

Repairs and adjustments qualifying under this special coverage must be performed by a General Motors dealer. Repairs may be performed by any authorized GM dealer. You may want to call the service department at the dealer to find out how long they will need to have your vehicle so that you may schedule the review at the most convenient time for yourself. This will also allow your dealer to order parts if they are not already in stock. Keep this letter with your other important glovebox literature for future reference.

Should your dealer be unable to schedule a service date within a reasonable time, you should contact the appropriate Customer Assistance/Relations Center at the listed number below:

Deaf, Hearing Impaired Division Number or Speech Impaired* ---------- -------------- ---------------------- Chevrolet 1-800-222-1020 1-800-833-2438 GMC 1-800-462-8782 1-800-462-8583 Oldsmobile 1-800-442-6537 1-800-833-6537

* Utilizes Telecommunication Devices for the Deaf/Text Telephones (TDD/TTY)

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

<Division(s)> GENERAL MOTORS CORPORATION

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.