XT-6 2WD L6-2.7L SOHC (1989)
Steering Control Module: Technical Service Bulletins
P/S Electronic-Controlled System Supplement
NUMBER:
04-06-91
DATE:
09-11-91
APPLICABILITY
XT6 VEHICLES
SUBJECT:
ELECTRONIC-CONTROLLED MOTOR DRIVE POWER
STEERING SYSTEM DIAGNOSTIC AIDS
This Service Bulletin is intended to supplement existing information currently available. Be sure to refer to the applicable Service Manual as well as the
Service Manual Correction issued on this subject in Service Bulletin Number 01-126-91, Dated 02-22-91.
Should you encounter a customer complaint of a continuous or intermittent steering warning lamp illumination which may or may not be accompanied by
a steerability complaint, please be aware of the following information.
Power Controller:
Product changes were made to improve reliability of this item starting with 1991MY VIN 300008. Modified power controllers
can be identified by a four-digit lot number found on a label on the unit. Lot numbers of 9913, or September 13, 1989 or newer
have been modified. Lot numbers are read as follows:
Signal Controller:
Product changes were made to improve reliability of this item as well. This unit was modified and introduced at approximately
the start of 1991MY production. Modified units can be identified by a label with the latest unit having a label number of
302-00102. Earlier units had 302-00101.
When a complete check of the system, using information presented here and in the service manual fails to address the customer complaint, we
recommend upgrading the power and signal controllers to the modified units.
Other items which should be checked prior to any parts replacement are:
1.
The condition of the battery and charging system should be confirmed as well as a thorough check of all applicable electrical connections. A
fully charged battery is critical to the operation of this system and should never be overlooked during initial diagnosis.
2.
"D" check as described in the service manual.
3.
Grounds: check the ground wire located under the console. FBI started using a longer bolt and quality controlling this item starting with 1988
MY VIN 310352. If in doubt concerning this connection, back up the bolt with a nut from underneath the vehicle to ensure a tight connection.
4.
Wire shielding: check all shielded wiring at the signal and power controller as well as the steering and temperature sensors for unintentional
grounds or short circuits. The wire shielding must be examined very closely for loose ends or fraying since even one or two loose strands may
cause a problem.
5.
Steering angle sensor: It is possible the steering angle sensor (located on the steering column) is inoperative because of an interference
condition between the steering angle sensor and the sensor plate. The sensor should be adjusted so that the plate is located in the center of the
sensor on both sides. Be sure no contamination from floor mats or other outside influences has affected this item.
This item may be at fault if the vehicle exhibits a loss of assist in a stopped condition with the MPS light off, only to have steering assist return
once the vehicle has moved and reached a speed of at least 6 mph.
6.
Motor pump: A possibility exists for the motor pump to exhibit an uneven wear of the brushes and commutator.
7.
It is recommended that only the FHI specified power steering fluid, Idemitsu, be used. Small amounts of Dexron II ATF fluid may be used in
the system on a temporary basis, if necessary. Larger amounts of Dexron II or use in cold, ambient temperatures may cause a performance
deterioration.
