Engine Controls - Droning Sound/Hesitation At 38-45 MPH
NUMBER: 18-012-10GROUP: Vehicle Performance
DATE: April 14, 2010
THIS BULLETIN SUPERSEDES SERVICE BULLETIN 18-023-09, DATED JULY 31, 2009, WHICH SHOULD BE REMOVED FROM YOUR FILES. ALL REVISIONS ARE HIGHLIGHTED WITH **ASTERISKS** AND INCLUDE AN ADDITIONAL VEHICLE MODEL.
THE wiTECH DIAGNOSTIC APPLICATION IS THE PREFERRED METHOD FOR FLASHING ECUs.
HELP USING THE wiTECH DIAGNOSTIC APPLICATION FOR FLASHING AN ECU IS AVAILABLE BY SELECTING "HELP" THEN "HELP CONTENTS" AT THE TOP OF THE wiTECH DIAGNOSTIC APPLICATION WINDOW.
THE wiTECH SOFTWARE LEVEL MUST BE AT RELEASE 10.03 OR HIGHER TO PERFORM THIS PROCEDURE.
StarMOBILE DESKTOP CLIENT or StarSCAN MAY ALSO BE USED TO PERFORM THIS PROCEDURE.
SUBJECT:
Flash: Drone Sound Or Hesitation Feel Between 38 To 45 MPH (61 To 72 km/h)
OVERVIEW:
This bulletin involves selectively erasing and reprogramming the Powertrain Control Module (PCM) with new software.
MODELS:
2007 - 2008 (KA) Nitro
2008 (KK) Liberty
2008 (KK) Cherokee (International Market)
**2008 (K1) Cherokee (CKD)**
NOTE:
This bulletin applies to vehicle equipped with a 3.7L engine (sales code EKG).
SYMPTOM/CONDITION:
Some customers may complain of a drone sound or a condition that feels like an irregular, very short, slight deceleration as if the vehicle is being "tugged" from behind. This condition exists between 1000 and 1600 rpm, 38 to 45 mph (61 To 72 km/h) at constant speed. This condition will be more noticeable during a light acceleration within the 38 to 45 mph (61 To 72 km/h) vehicle speed.
This new software update has removed 3rd gear partial lockup and raised the 4th gear full lockup speed to 50 mph.
DIAGNOSIS:
Using a Scan Tool (wiTECH or StarSCAN(R)) with the appropriate Diagnostic Procedures available in TechCONNECT, verify all engine systems are functioning as designed. If DTC's are present record them on the repair order and repair as necessary before proceeding further with this bulletin.
PARTS REQUIRED:
REPAIR PROCEDURE:
NOTE:
If this flash process is interrupted/aborted, the flash should be restarted.
1. Reprogram the PCM with the latest software. Follow the detailed service procedures available in DealerCONNECT/TechCONNECT, Refer To Group 8 - Electrical > Electronic Control Modules - Service Information > Module - Powertrain Control > Standard Procedures > PCM/ECM Programming - Gas. After PCM reprogramming, the following must be performed:
a. Clear any DTC's that may have been set in other modules due to reprogramming. The wiTECH application will automatically present all DTCs after the flash and allow the tech to clear them.
2. Type the necessary information on the "Authorized Modification Label" and attach it near the VECI label.
POLICY:
Reimbursable within the provisions of the warranty.
TIME ALLOWANCE:
FAILURE CODE:
Disclaimer:
This bulletin is supplied as technical information only and is not an authorization for repair.