Stratus Sedan L4-2.4L VIN X (2003)
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VF display dimming brightness and exterior lamp status
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Trip Odometer data
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Elapsed Ignition On Time data
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Fuel Economy
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Distance to Empty
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Outside Temperature
The CMTC transmits the following messages to the BCM:
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Status Request: Beep, Reset, US/M Toggle
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Current Display
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Compass Heading
The CMTC receives the following message from PCM:
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Vehicle Speed
Setting Magnetic Zone Variance
Variance is the difference between magnetic North and geographic North. For proper compass function, the correct variance zone must be set. Refer to
the Zone Variance map for the correct zone. Follow these steps to check or change the variance zone:
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The ignition switch must be in the On position and the CMTC display must not be blank.
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Press and hold the STEP and US/M buttons until VAR is displayed. The CMTC will display the last variance zone stored in memory and the word
VAR.
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Use the STEP button to select the proper variance zone number, 1 through 15.
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After selecting the proper zone number, simultaneously press the STEP and US/M buttons or wait approximately 15 seconds. The variance zone is
then stored in the memory and the CMTC returns to normal operation.
COMPASS CALIBRATION
The compass module has 2 types of auto-calibration; slow-cal and fast-cal. Slow-cal ensures that during normal vehicle operation the compass
performs auto-calibration functions to keep the compass sensors in their proper operating range. Whenever the ignition is On and the CMTC receives
PCI bus data indicating that engine RPM is greater than zero, auto-calibration is performed continuously.
If the calibration information stored in the compass module memory is not within the normal range after a power-up cycle, the compass will display
CAL. The CMTC with enter into the fast-cal mode until calibration is complete.
To enter the compass into Manual Calibration mode, perform the following steps:
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Drive the vehicle to an area away from any large metal objects or overhead power lines.
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Ensure that the proper variance zone is selected. See "Setting Magnetic Zone Variance."
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The ignition switch must be in the On position and the CMTC display must not be blank.
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Press the STEP button and scroll to the Compass/Temperature display.
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Press and hold the STEP and US/M buttons simultaneously until CAL begins flashing and then release the buttons.
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CAL is displayed without flashing.
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Drive slowly, less than 4 MPH (8 KPH) in 3 complete 360 degree circles.
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CAL will remain illuminated to alert the driver that the compass is in the calibration mode.
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After calibration is complete, CAL will turn off.
If the compass appears unable to be calibrated or the compass displays false indications, the vehicle may need to be demagnetized.
Ambient Temperature Sensor
The ambient air temperature is monitored by the PCM and displayed by the CMTC. The PCM receives a hardwire input from the ambient temperature
sensor(ATS). The ATS is located on the inside of the front bumper beam.
The ATS cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.
The ATS is a variable resistor that operates on a 5-volt reference signal circuit hardwired from the PCM. The resistance in the ATS changes as the
outside temperature rises or falls. The PCM senses the change in reference voltage through the ATS resistor. Based on the resistance of the ATS, the
PCM is programmed to correspond to a specific temperature. The PCM then transmits the proper ambient temperature to the BCM. The BCM filters
the ambient temperature data and transmits this data to the CMTC.
DIAGNOSIS AND TESTING
Self-check Diagnostics
The CMTC is capable of performing a diagnostic self check on its internal functions. CMTC diagnostics may be performed using a DRBIII(R) or by
using the following procedure:
1. With the ignition switch in the OFF position, depress and hold the STEP and the US/M buttons.
2. Turn the ignition switch to the On position and release the buttons.
