Fleetwood V8-5.7L VIN P (1994)
PROM - Programmable Read Only Memory: Customer Interest
AIR Pump - Hesitation on Acceleration/DTC 48 Set
File In Section: 06 - Engine/Propulsion System
Bulletin No.: 01-06-04-019
Date: March, 2001
TECHNICAL
Subject:
Water in AIR Pump and/or DTC 48
(Install AIR Pump Service Kit)
Models:
1994
Buick Roadmaster
1994
Cadillac Fleetwood
1994
Chevrolet Caprice
with 4.3 L or 5.7 L V8 Engine (VINS W, P - RPOs L99, LT1)
This bulletin is being revised to delete reference to 1995 and 1996 vehicles. Please discard Corporate Bulletin Number 77-65-13 (Section 6 - Engine).
Condition
Some customers may comment on a hesitation during heavy/full throttle acceleration. Some vehicles may also set a DTC 48. There will also be evidence
of water in the AIR Pump.
Cause
Under high engine speed and load conditions, hot exhaust gasses may leak past the AIR check valves. As the exhaust gasses in the air tube cool, water
vapors collect into the AIR Pump. When the vehicle is driven, condensation from the AIR Pump may come into contact with the mass air flow sensor.
This condition may cause a hesitation on acceleration and may also set the DTC.
Correction
Verify AIR Pump operation using a scan tool. Inspect the AIR Pump for traces of water. If the AIR Pump shows indication of water intrusion, install an
AIR Pump service kit.
Important:
Inspect the AIR check valves by using a hand vacuum pump. Apply 10 inches of vacuum to the AIR hose side of the check valve. Vacuum should
hold for at least 10 seconds. If not, replace the AIR check valves.
Parts Information
Parts are currently available from GMSPO.
The AIR Pump Service kit, P/N 12558522 includes as shown in the table.