Engine Controls - Service A/C Telltale & Codes F46/F47

89cadillac06

Bulletin No. T-89-95
File in Group 1
Number 62
Corp. Ref. No. 911201
Date April, 1989

SUBJECT: SERVICE AIR CONDITIONING TELLTALE ACCOMPANIED BY CODES F46 AND/OR F47

MODELS AFFECTED: 1988-1989 DE VILLES AND FLEETWOODS


Some 1988-1989 DeVilles and Fleetwoods that have sufficient air conditioning performance may experience a "Service Air Conditioning" telltale light with a false code F46 and/or F47 (A/C refrigerant system condition) that sets in ambient temperatures of 55-65~ F. The F46 and/or F47 code(s) are designed to set when a "low refrigerant" condition exists to protect the compressor.

This condition may be caused by a BCM PROM with an I.D. of:

I.D. Model Year

22 or 23 1988 DeVille/Fleetwood
30 1989 DeVille/Fleetwood

The BCM PROM I.D. can be checked by entering diagnostics and selecting BCM parameter P.3.1 as described in Section 8D of the appropriate Cadillac Service Information Manual.

To repair this condition, replace the BCM PROM with the appropriate part number listed below:

Model Service Broadcast PROM
Year Part Number Code I.D.

1988 (all except commercial chassis) 16122026 NAU 24
1988 (commercial chassis) 16122030 ANAW 224
1989 16138772 ARZT 31

Part number 16138772 is currently available from GMSPO. Part numbers 16122026 and 16122030 are expected to be available on April 3, 1989. Until then, normal part orders will not be accepted by GMSPO. Only verifiable emergency VIP orders will be accepted. SPO will make every effort to obtain parts. All parts will be placed on 400 control to waive VIP surcharges. However, the part will be shipped premium transportation at dealer's expense. All other order types will be cancelled as incorrectly ordered while the 400 control is in place.

IMPORTANT: The above PROM's also contain a purge feature that directs airflow to floor ducts at a high fan speed for 4.5 seconds when ignition is first turned on and A/C is required.

If replacing the BCM PROM does not repair this condition, perform a leak check on the refrigerant system. When checking for refrigerant leaks, the use of an electronic leak detector, J-29547 or equivalent, is recommended. When using the leak detector, check the bottom of the fittings at all connections because refrigerant is heavier than air.

Two system areas that should be checked thoroughly are the hose assembly at the compressor (any signs of oil leakage) and that all Schrader valve caps are tight because the cap O-ring is the primary seal.

If no leaks are found, discharge the refrigerant system as described in the appropriate Cadillac Service Information Manual, then check the orifice tube for debris and proper installation. The flow indication arrow on the orifice tube should point toward the evaporator.

Recharge system and check for leaks using an electronic leak detector.


WARRANTY INFORMATION VEHICLE SERIES
Operation
Operation Description Number C D E J K V

Computer (Control), Body - Replace PROM N4801 .4


Policy: E