Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET1991R 30 P/U 2WD V8-454 7.4LREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSVEHICLE SPEED SENSORTECHNICAL SERVICE BULLETINSDIGITAL RATIO ADAPTER/CONTROLLER (DRAC) - SERVICE
1991 Chevrolet R 30 P/U 2WD V8-454 7.4L
Digital Ratio Adapter/Controller (DRAC) - Service
1991 Chevrolet R 30 P/U 2WD V8-454 7.4LSECTION Digital Ratio Adapter/Controller (DRAC) - Service
Group Ref.: 8 - Chassis/Body Electrical
Bulletin No.: 448301
Date: August, 1994
INFORMATION
SUBJECT:
NEW PROCEDURE FOR OBTAINING SERVICE DRACS
(DIGITAL RATIO ADAPTOR/CONTROLLER)
MODELS:
1989-94 CHEVROLET AND GMC TRUCK M/L VANS, S/T MODELS
1990-94 CHEVROLET AND GMC TRUCK G VANS, R/V MODELS
1992-94 CHEVROLET AND GMC TRUCK C/K MODELS
1991-94 OLDSMOBILE BRAVADA
If a dealer is contacted about or is in need of a service DRAC (Digital Ratio Adaptor/Controller) for any of the following reasons:
1. Radio interference (EMI).
2. Speedometer fluctuation or flaring.
3. Erratic/surging cruise control operation.
4. Different tire size.
5. Defective part.
The dealer must contact an AC-Delco Service Center authorized to repair electronic instrument clusters for a new service DRAC, P/N 16202915.
NOTE:
This part is a service part and has to be programmed for the vehicle. It cannot be used until this procedure has been done by the authorized Service Center.
The dealer will need the P/N and the broadcast code (the 3 bold letters located on the printed label of the old DRAC). The Service Center will program the DRAC according to this information.
If the customer is changing the tire size, the Service Center will need the axle ratio and tire sized in order to program the DRAC to the new tire specifications. The AC-Delco Service Center will send the programmed DRAC via common carrier to the dealership.
For further information, consult the AC-Delco authorized Service Center Manual WA-2 (September 1990 or later). AC-Delco centers are subject to change.
Bulletin No.: 448301
Date: August, 1994
INFORMATION
SUBJECT:
NEW PROCEDURE FOR OBTAINING SERVICE DRACS
(DIGITAL RATIO ADAPTOR/CONTROLLER)
MODELS:
1989-94 CHEVROLET AND GMC TRUCK M/L VANS, S/T MODELS
1990-94 CHEVROLET AND GMC TRUCK G VANS, R/V MODELS
1992-94 CHEVROLET AND GMC TRUCK C/K MODELS
1991-94 OLDSMOBILE BRAVADA
If a dealer is contacted about or is in need of a service DRAC (Digital Ratio Adaptor/Controller) for any of the following reasons:
1. Radio interference (EMI).
2. Speedometer fluctuation or flaring.
3. Erratic/surging cruise control operation.
4. Different tire size.
5. Defective part.
The dealer must contact an AC-Delco Service Center authorized to repair electronic instrument clusters for a new service DRAC, P/N 16202915.
NOTE:
This part is a service part and has to be programmed for the vehicle. It cannot be used until this procedure has been done by the authorized Service Center.
The dealer will need the P/N and the broadcast code (the 3 bold letters located on the printed label of the old DRAC). The Service Center will program the DRAC according to this information.
If the customer is changing the tire size, the Service Center will need the axle ratio and tire sized in order to program the DRAC to the new tire specifications. The AC-Delco Service Center will send the programmed DRAC via common carrier to the dealership.
For further information, consult the AC-Delco authorized Service Center Manual WA-2 (September 1990 or later). AC-Delco centers are subject to change.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.