6000 V6-173 2.8L (1988)
PROM - Programmable Read Only Memory: Customer Interest
Engine Controls - Driveability/Codes 23, 25, 33 or 34
Bulletin Number:
88-6-98D
Reference Number:
936518R
Publish Date:
5/90
Subject:
DRIVEABILITY CONDITIONS - 2.8L AND/OR STORED ENGINE CODES 23, 25, 33 OR 34, (PROCEDURE AND PROM)
Models
Affected:
1987-88 6000 and 1988 GRAND PRIX MODELS
This bulletin has been revised to add additional steps to clean the throttle body under 3C and information under 3I. This bulletin cancels and replaced
bulletin 88-6-98C.
Some customers with an engine/vehicle combination listed below
1988 Grand Prix Models - With a 2.8L Engine (Vin Code W) 1987-88 6000 Models With a 2.8L Engine (Vin Code W) may comment that they have
experienced one or more of the following conditions:
A cold start stall or sag, A decel stall
A tip-in hesitation
A check engine light with stored Codes 23, 25, 33, 34 or
An engine speed flare during a declutch operation with a manual transmission equipped vehicle.
These conditions may be attributed to a number of components/interactions. In the interest of simplifying diagnosis and repair, the following procedure
has been developed to reduce system sensitivity, thereby addressing a variety of potential causes simultaneously.
If a customer comment concerning an occasional engine stall or a drive hesitation is received, and/or a stored Code 33 or 34 is found, then complete the
following procedure:
1.
Perform diagnostic procedures per Section 6E of the Service Manual, and correct any faults except for Codes 33, 34, 23 or 25. If the
diagnostics indicate the Mass Air Flow (MAF) is to be replaced or a Code 33 or 34 is present, DO NOT REPLACE THE MAF SENSOR!
Proceed to Step # 3. If a Code 23 or 25 is present, go to Step # 2 below. PROCEED TO STEP # 3 ONLY IF NORMAL DIAGNOSTIC
CHECKS DID NOT IDENTIFY A CAUSE FOR THE CUSTOMER CONCERN.
2.
If a Code 23 or 25 is stored, perform the model year diagnostics for the Manifold Air Temperature Sensor (MAT). If the diagnostics indicate
that the MAT is faulty and replacement is required, replace the combination MAT/MAF sensor. Proceed to Step # 3.