Stratus L4-2.0L VIN C (1997)
If a malfunction is detected, a diagnostic trouble code is stored and will remain stored as long as the malfunction exists. When and if the
malfunction ceases to exist, an ignition cycle count will be initiated for that code. If the ignition cycle count reaches 100 without a reoccurrence of
that same malfunction, that diagnostic trouble code is erased and that ignition cycle counter is reset to zero. If the malfunction reoccurs before the
count reaches 100, then the ignition cycle counter will be reset and the diagnostic trouble code will continue to be a stored code.
If a malfunction is not active while performing a diagnostic test procedure, the active code diagnostic test will not locate the source of the problem.
In this case, the stored code can indicate an area to inspect.
If no obvious problems are found, erase stored codes, and with the ignition "on," wiggle the wire harness and connectors, rotate the steering wheel
from stop to stop. Recheck for codes periodically as you work through the system. This procedure may uncover a malfunction that is difficult to
locate.
Manual A/C (HVAC) - Mode Door Operation
MANUAL A/C (HVAC) MODE DOOR OPERATION
The DRB trouble codes that indicate a stall failure or a feedback signal failure work together to show what is wrong with the HVAC system.
The stall trouble codes mean that the Body Control Module (BCM) cannot force an actuator to the end of the mode door travel. Internal problems
in the body control module will set other short-related trouble codes. Having only stall trouble codes indicates that there is a problem with an open
or short circuit in the wiring, a bad actuator, a bad mode door or connecting linkage. It is important that the operation of the mode door be checked
if an actuator is removed. This can be checked by rotating the door shaft to confirm that the door will stop at both ends of travel. The actuator
itself has no stops. It must have the mode door to stop travel to pass the stall test.
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.
Diagnostic Strategies
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.
