Unnecessary Catalytic Converter Replacements (18 01 99)

Publication date: 1999-09-01
Reference number: 18 01 99

UNNECESSARY CATALYTIC CONVERTER REPLACEMENTS

TECHNICAL SERVICE BULLETIN

Reference Number(s): 18 01 99, Date of Issue: September, 1999
Superceded Bulletin(s): 18 01 99, Date of Issue: August, 1999

UNNECESSARY CATALYTIC CONVERTER REPLACEMENTS

Model(s): 1995-1997 BMW 850Ci

1995-on BMW 750iL

1996-1997 BMW 318is, 318iC, 840Ci

1996-1998 BMW 318i

1996-1999 BMW 318ti, 328is, 328iC, M3

1996-on BMW 328i, Z3, 740iL

1997-on BMW 528i, 540i, 740i

1998-1999 BMW 323is, 323iC

1999-on BMW 323i, 528iT, 540i, M

2000-on BMW 323Ci, 328Ci

Group: 18 - Exhaust System

Bulletin No.: 18 01 99

Date: September, 1999

NOTE: This bulletin supersedes Service Information Bulletin 18 01 99 dated August, 1999.

MODELS AFFECTED

E36 with M44 engine from 1/96 prod.
Z3 with M44 engine from 10/96 prod.
E36 with M52, S52 engines from 10/95 prod.
E46 with M52 engine from 6/98 prod.
E39 with M52 engine from 3/96 prod.
Z3 with M52, S52 engines from 1/96 prod.
E38, E39, E31 with M62 engine from 1/96 prod.
E38, E31 with M73 engine from 1/95 prod.

SITUATION

Analysis of returned catalytic converters has proven that some converters are not defective and are replaced unnecessarily.

The reason for unnecessary converter replacements may be due to the misfire fault code(s) in conjunction with the statement "catalyst damaging" being stored in the Engine Control Module (ECM/DME).

Example: Fault Codes 63 - 70: "Cylinder misfire detected - catalyst damaging"

If a vehicle is found with the "Check Engine" lamp on and one or more misfire faults are stored in the engine control module, the fault code description "cylinder X misfire detected - catalyst damaging" will be displayed on the diagnosis fault survey of the DIS or MoDiC.

The qualifier "catalyst damaging" is a reminder that this type of fault (cylinder misfire) may over time cause damage to the catalytic converter if it is not repaired.

Troubleshooting cylinder faults should be carried out using the DIS or MoDiC i.e. check secondary ignition system, etc.

A catalytic converter should not be replaced automatically when a "... - catalyst damaging" fault code is stored in the Engine Control Module.

A catalytic converter replacement is only necessary if fault codes 40, 45 or 233 (E9 hex), 234 (EA hex) are stored in the Engine Control Module which are catalytic converter efficiency or conversion faults and/or if a customer complaint of an audible rattle noise coming from the converter is verified.

WARRANTY INFORMATION

Information only.