Operation CHARM: Car repair manuals for everyone.

MIL ON, Engine Misfire DTC's Set: Overview

NO: 18-22-98

GROUP: Vehicle Performance

DATE: Jun. 12, 1998

SUBJECT:

OBD II Misfire Monitor

THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 18-31-97, WITH EFFECTIVE DATE OF JAN. 30, 1998 WHICH SHOULD BE REMOVED FROM YOUR FILES AND NOTED IN THE 1997 TECHNICAL SERVICE BULLETIN MANUAL (PUBLICATION NO. 81-699-98004). THE DECARBONIZING PROCEDURE HAS BEEN REVISED ALONG WITH THE LABOR OPERATION TIME ALLOWANCE. ALL REVISIONS ARE HIGHLIGHTED WITH **ASTERISKS**.

MODELS:

1997 - 1998 (TJ) Wrangler
1996 - 1998 (XJ) Cherokee
1996 - 1998 (ZJ) Grand Cherokee

NOTE:
THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH THE 4.0L ENGINE.

SYMPTOM/CONDITION:

Malfunction Indicator Lamp (MIL) illuminated with either a Multiple Misfire or individual Cylinder (1-6) Misfire Diagnostic Trouble Code (DTC) recorded in the Powenrain Control Module's (PCM) memory. The MIL illumination may be accompanied by engine vibration.

DIAGNOSIS:

Refer to the 1998 2.5L/4.0L/5.2L/5.9L SF1 Jeep Powertrain Diagnostic Procedures Manual (Publication No. 81-699-97019), test TC-106A for the Multiple Cylinder Misfire DTC or test TC-107A for the Cylinder # (1-6) Misfire DTC. For any future reference, record and document Freeze Frame data.

NOTE:
BOTH TEST TC-106A AND TC-107A ARE REVISED WITH TECHNICAL SERVICE BULLETIN 26-12-97 RELEASED DECEMBER 1997. DO NOT USE THE PROCEDURE LISTED IN THE DIAGNOSTIC PROCEDURE MANUAL UNLESS THE REVISED PAGES HAVE BEEN INSERTED.

Perform the repair procedure identified in the Powertrain Diagnostic Procedures Manual unless your diagnosis identifies that an engine mechanical problem could be causing the OBD II Misfire DTC. If the Powertrain Diagnostic Procedures Manual identifies a possible engine mechanical problem, perform the Repair Procedure.

PARTS REQUIRED:

12 53010388 Springs, Valve
1 04318001 Mopar Combustion Cleaner

POLICY: Reimbursable within the provisions of the warranty.

TIME ALLOWANCE:

Labor Operation No: **09-95-20-92 3.1 Hrs.**

FAILURE CODE: XX - Service Adjustment