For 1990-2009 cars

# Info on Utra Low Sulfur Diesel Fuel and Warning Labels on Fuel Station Pumps -This Info Applies to Diesel Engines w/RPOs LBZ, LB7, LH6, LLY, LMM, LL4, LQM, LQN, L49, L56, L57, L65, LG4, 1C3, 1C2, 1L5

Subject: | Information On Ultra Low Sulfur Diesel Fuel and Warning Labels Found On Fuel Station Pumps -- Applicable to All Light and Medium Duty Diesel Engines with RPO codes LBZ, LB7, LH6, LLY, LMM, LL4, LQM, LQN, L49, L56, L57, L65, LG4, 1C3, 1C2, 1L5

Models: | 1997-2007 GM Light Duty and Medium Duty Trucks

| with 6.6L V8 Diesel Engine (VINs D, 1, 2, 6 -- RPOs LBZ, LB7, LLY, LMM)

| with 6.5L V8 Diesel Engine (VINs F, P, S, T, Y -- RPOs LQM, LQN, L49, L56, L65, L57)

| with 6.2L V8 Diesel Engine (VINs C, J -- RPOs LH6, LL4)

| 1999-2007 Chevrolet W-Series Medium Duty Tilt Cab Models

| 1999-2007 GMC W-Series Medium Duty Tilt Cab Models

| 1999-2007 Isuzu N-Series Commercial Models

| with 4HE1 (4.75L), 4HK1 or 5.2L Diesel Engine (VINs 4, 5, 6 -- RPOs 1C3, 1C2, 1L5)

| 2003-2007 Chevrolet C and T Series Medium Duty Trucks

| 2003-2007 GMC C and T Series Medium Duty Trucks

| 2003-2007 Isuzu H and F Series Medium Duty Commercial Models

| with 7.8L Diesel Engine (VIN 3 -- RPO LG4)

Some fuel companies may be putting warning labels on their diesel fuel pumps. The warning labels will describe the sulfur content of the fuel. It will also advise customers not to use a 500 ppm sulfur fuel in a 2007 or later vehicle. Refer to the graphic illustration above.

At this time, customers may find more than one type No. 2 diesel fuel available:

• | LSD (low sulfur diesel fuel) is diesel fuel with 500 ppm sulfur content.

• | ULSD (ultra low sulfur diesel fuel) has a sulfur content of 15 ppm or lower.

• | Off Road Fuel with a 500 ppm or higher sulfur content

All fuel companies will start transitions to ULSD (15 ppm sulfur max) in mid-2006. Refineries in the U.S. and Canada are required to start producing ULSD on June 1. U.S. and Canadian supply terminals must be converted to ULSD by September 1 and retail stations must be converted by October 15.

In the U.S., both LSD (500 ppm sulfur) and ULSD (15 ppm sulfur) will be available. However, the EPA's own pre-compliance reports indicate that 95% of on-road diesel fuel will meet the 15 ppm standard on a nationwide basis. All LSD (500 ppm sulfur) and Off Road Fuels (greater than 500 ppm sulfur) must be segregated and clearly marked. In Canada, only 15 ppm on-road diesel fuel will be available nationwide by October 15th.

Below is a description of GM vehicles and proper fuel usage:

In January of 2007, a new 6.6L Duramax™ Diesel (RPO LMM-eighth digit of the VIN is a 6) will be released. This 6.6 LMM engine must use the ULSD (ultra low sulfur diesel) fuel. The 2007 "LMM" diesel equipped vehicles will require the use of ULSD for proper operation of the emission control system. These vehicles will be labeled "ULSD Required." The vehicles will be labeled in two locations (per regulation) near the fuel filler and on the IP. The Owner's Manual and diesel supplement will have several instances/sections that define proper fuel use.

Important:: Off Road Fuels should not be used in any General Motors highway use vehicles.

All other Light and Medium Duty 6.2L, 6.5L, and 6.6L RPO codes LB7, LBZ, and LLY diesel engines (including 2007 model year LBZ and LLY) can use either the LSF (low sulfur diesel) or ULSF (ultra low sulfur) diesel fuels.