Diagnostic Parameters & Displays
STATUS DISPLAY
While in the diagnostic mode, the mode indicators on the ECC Head are used to indicate the status of certain system operating modes, see illustration. The different modes of operation are indicated by the status light either being turned ON or OFF. A brief summary of each status light is provided below:
1. The OUTSIDE TEMP status indicator is turned ON whenever the ECC head is requesting the compressor clutch to engage. This light only indicates whether the clutch is enabled or disabled by the ECC head. Actual operation depends on the integrity of the compressor clutch system. The ECC head requests an A/C clutch engagement based on information supplied by its inputs and ECM inputs as described previously. A request is then sent from the ECC head to the ECM which has direct control of the A/C compressor clutch relay (5.0 Liter system). The ECM may inhibit this apply request due to various engine operating conditions (i.e. wide open throttle, high power steering load, etc.).
2. The °F status indicator is turned ON whenever the ECC head senses that the refrigerant low pressure switch is open. This light will come ON when the ambient temperature falls below approximately -5°F due to the pressure temperature relation ship of refrigerant -12. This light should remain OFF under all other conditions if the refrigerant system is fully charged.
3. The °C status indicator is turned ON whenever he ECC Head is commanding the heater water valve to block coolant flow through the heater core. This light should remain OFF except when the air mix valve is being commanded to the Maximum A/C position (0).
4. The Lo FAN status indicator is turned ON whenever the ECC head is commanding the A/C`HTR mode valve to divert air flow to the A/C outlets as in the A/C mode. This light will be OFF whenever the ECC system is in the HEATER HEATER/DEFROST, DEFROST.
5. The HI FAN status indicator is turned ON whenever the ECC head is commanding the DEF/HTR mode valve to divert air flow up away from the heater outlet to the defrost outlet. This light will be OFF whenever the ECC system is in the HEATER mode.
ECC PARAMETER
To display ECC parameter data information, proceed as follows, illustration:
1. Depress and release the outside temp button on the ECC Head. The ECC parameter series begins as the display switches from Code Display to parameter number display. It is possible to leave the ECC parameter series at anytime and return to parameter -00 by clearing ECC codes.
2. To advance the parameter display, depress the HI button on the CCP. To return to a lower number parameter or jump directly to the end of the parameter list, depress the LO button the CCP.
3. Switch between parameter number display (distinguished by a preceding minus sign) and parameter value display by pressing the outside temperature button.
4. When troubleshooting a malfunction, the ECC data display can be used to compare the vehicle with problems to a vehicle which is functioning properly. A brief summary of each parameter is provided below:
Parameter Summary
-02 The ECC program number is read in counts between '0' and '255'.
-10 The ignition voltage (battery) is read in volts.
-11 The ECC program number is read in percentage between '0' and '100'. While in this display, ECC program override may be initiated.
-12 The vehicle speed is displayed in mph between '0' and '199'.
-19 The actual blower voltage is displayed in volts.
-20 The commanded blower voltage is read in volts.
-21 The coolant temperature is displayed in degrees Celsius (°C).
-22 The command air mix valve position is displayed counts (0-255). A value close to '200' represents a cold air mix and a value close to '0' represents a warm air mix.
-23 The actual air mix valve position is displayed in counts (0-255). This value should follow the commanded air mix valve position (-22) except when the valve is commanded beyond its mechanical limits of travel.
-24 The air delivery mode is displayed as a number from '0' to '6'. Each number is a code which represents the following air delivery models.
0 = Max A/C
1 = A/C
2 = Tri-Mode
3 = Heater
4 = Defrost
5 = Delay
6 = OFF
-25 The in-car temperature is displayed in degree Celsius (°C).
-26 The actual outside temperature is displayed in degrees Celsius (°C). This value represents actual sensor temperature and is not restricted by the features used to minimize engine heat effects on the customer display value.
-28 The low side temperature (evaporator inlet) is displayed in degrees Celsius (°C).
-29 This parameter is used to distinguish the ECC's version, 5.0 or 5.7 liter. 5.0 liter application will display '00', 5.7 liter will display '01'.
-30 The ignition cycle counter value is the number of times that the ignition has been cycled to OFF or start since a trouble code was last detected. After 199 ignition cycles without any malfunction being detected, all ECC codes are cleared and the counter is reset to '0'.
-31 The ECC head Calibration is displayed as a number up to three digits long which can be used to verify that the proper HVAC Calibration was installed in the ECC head.
ECC PROGRAM OVERRIDE
During the display of ECC program number on the ECC Head, it will display a two digit number which represents the ECC program number. This number represents various levels of heating and cooling effort. As parameter -02 or -11 first appears on the ECC Head, it will begin displaying the program number which is currently being used by the ECC system. As operating conditions change, this number will automatically change in response.
The automatic calculation of program number can be bypassed by a manual override feature using the WARMER or COOLER buttons (see illustration). While in this display, pressing the WARMER button will force the program number to increase at a controlled rate until the maximum value is realized which represents Max Heat. Pressing the COOLER button will force the program number to decrease until the value of 0 is reached which represents the Max A/C mode.
This manual override of automatic program number calculation will continue until exit from diagnostics. This allows the service technician to control the program number to any number from Max A/C to Max Heat and simultaneously observe the reaction of any of the ECC parameter values.