MIL ON - DTC P0300/P0301-P0304, Misfire: Overview

BULLETIN NO.: 98-T-14A

ISSUE DATE: August, 1999

GROUP/SEQ. NO.: Engine-01

CORPORATION NO.: 99-06-04-034

SUBJECT:
(MIL) SERVICE ENGINE SOON Light On with DTCs P0300 and/or P0301-P0304, Engine Misfire-SOHC (L24) Engines (Install Service Calibration and/or Repair as Required)

This bulletin has been revised to include valve guide Go/No-Go Gauge special tool (J43120) and ignition coil (P/N 16167763). This bulletin supercedes bulletin 98-T-14, which should be discarded.

MODELS AFFECTED:
1996-1997 Saturn S-Series vehicles equipped with SOHC (L24) engines

CONDITION:
Vehicles equipped with SOHC (L24) engines may experience the malfunction indicator lamp (MIL) (SERVICE ENGINE SOON telltale lamp) On with DTCs P0300 and/or P0301, P0302, P0303, or P0304.

CAUSE:
Misfire DTCs can be caused by a number of conditions. Several of these conditions are addressed in this bulletin.

1. Electrical - ignition secondary, mechanical or fuel system component(s) malfunctioning.

2. Misfire caused by cold-start spark plug fuel-fouling or misfire DTCs setting inappropriately during non-catalyst damaging events, (calibration).

3. Deposit build-up on exhaust valve guides and exhaust valve stems, causing the exhaust valves to close too slowly during engine warm-up and hot driving conditions.

CORRECTION:

Refer to the Misfire Diagnostic Charts within this bulletin.

Begin with the Diagnostic Chart on the facing page. The steps in the Diagnostic Chart that contain a circled number (e.g. (01)) refer to the notes below. These notes provide additional detail on those specific steps in the Diagnostic Chart.





Notes on the Diagnostic Chart 1:





MISFIRE DIAGNOSTIC CHART 1

The steps in the Diagnostic Chart that contain a circled number (e.g. (01)) refer to the notes below. These notes provide additional detail on those specific steps in the Diagnostic Chart.





Notes on the Diagnostic Chart 2:





MISFIRE DIAGNOSTIC CHART 2





MISFIRE DIAGNOSTIC CHART 3





MISFIRE DIAGNOSTIC CHART 4





MISFIRE DIAGNOSTIC CHART 5





PCM CALIBRATIONS (CALIBRATION ID)





PARTS REQUIREMENTS:





CLAIM INFORMATION:
To receive credit for this repair during the warranty coverage period, submit a claim through the Saturn Dealer System as shown.

IMPORTANT:
Refer to 1996-1997 Labor Time Guide for repairs not listed above.