Stratus L4-2.4L DOHC (1995)
A feedback signal failure can occur on the mode door. The body control module monitors the feedback signal to check the position of the actuator.
The body control module not only checks the level of the signal but also how much the voltage changes.
A feedback failure can occur if there is a short or open circuit in the wiring, a bad actuator, a bad body control module, a bad mode door or
connecting linkage. The easiest way to diagnose this is to use the DRB to actuate the mode door. Note that the feedback voltage of the actuator
should smoothly change as the actuator is moved. A sudden change in the feedback voltage to a 5.0-volt or a 0.0-volt level indicates the actuator is
bad. A fixed feedback voltage that is less than 5.0 volts or greater than 0.0 volts without a stall failure, or a short failure indicates that the actuator,
the mode door, or a connecting mechanical linkage is jammed preventing movement. A feedback signal voltage that stays on 5.0 volts or 0.0 volts
indicates a wiring or body control module problem.
The feedback failure trouble code can also occur from a lack of actuator travel. This can be checked by confirming that the feedback signal
smoothly changes when the actuator is moved with the DRB. If the signal is ok, the door travel is not correct. The actuator must be removed and
the mode door mechanically checked for proper operation. Typical problems that prevent door movement include screws dropped in the A/C unit
or warped doors. Replace any part that is found defective.
Anytime the voltage to the BCM is interrupted for less than 2 minutes or voltage drops below approximately 10.0 volts (battery disconnected,
etc.), it may be necessary to recalibrate the mode door. This can be done by using the DRB, MDS machine or removing the IOD (M1) fuse for 10
seconds, reinstall it and then start the engine.
Six-Step Troubleshooting Procedure
VEHICLE PREPARATION FOR TESTING
Make sure the vehicle being tested has a fully charged battery. If it does not, false diagnostic codes or error messages may occur.
SIX-STEP TROUBLESHOOTING PROCEDURE
Diagnosis of the body system is done in six basic steps:
-
Verification Of Complaint
-
Verification Of Any Related Symptoms
-
Symptom Analysis
-
Problem Isolation
-
Repair Of Isolated Problem
-
Verification Of Proper Operation
Road Testing A Complaint Vehicle
ROAD TESTING A COMPLAINT VEHICLE
Some complaints will require a test drive as part of the repair verification procedure. The purpose of the test drive is to try to duplicate the
diagnostic code or symptom condition.
CAUTION: Before road testing a vehicle, be sure that all components are reassembled. During the test drive, do not try to read the DRB screen
while in motion. Do not hang the DRB from the rear view mirror or operate it yourself. Have an assistant available to operate the DRB.
