Operation CHARM: Car repair manuals for everyone.
Home >> Jeep >> 1998 >> Grand Cherokee 2WD L6-4.0L VIN S >> Repair and Diagnosis >> Powertrain Management >> PROM - Programmable Read Only Memory >> Technical Service Bulletins >> Customer Interest >> A/T - Overdrive Unavailable in Cold Temperatures >> Repair Procedure >> Overview
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Repair Procedure: Overview

This bulletin involves installing a cold weather by-pass kit to the transmission cooler circuit, selectively erasing and reprogramming the Powertrain Control Module (PCM) with new software (calibration changes for 1996 models only), and using the DRB III to selectively turn off the overdrive inhibitor feature for all applications.

NOTE:
IT IS ESSENTIAL THAT THE TRANSMISSION COOLER BYPASS KIT BE INSTALLED PRIOR TO DISABLING THE INHIBITOR FEATURE. TRANSMISSION DAMAGE MAY OCCUR IF THE BYPASS KIT IS NOT INSTALLED.

NOTE:
EVEN WITH BYPASS KIT INSTALLATION AND THE INHIBITOR FEATURE TURNED OFF, 4TH GEAR WILL BE INHIBITED UNTIL THE OIL SUMP TEMPERATURE REACHES 0 C (30 F). THIS MAY TAKE SEVERAL MINUTES.
pro multis · About Operation CHARM