Seville V8-300 4.9L (1991)
3.
After the segment check, any trouble code stored in computer memory will be displayed on the "Data Center." These trouble codes will appear
prefixed with an "E" for ECM/PCM codes, or "B" for BCM codes, or "R" for SIR codes, to designate which computer detected the malfunction.
The codes will be followed by an "H" (history) if the code is intermittent, or a "C" (current) if it is a hard code. If any trouble codes are displayed
or if diagnostics cannot be entered, refer to the SELF-DIAGNOSTIC CIRCUIT CHECK for the proper diagnostic procedure. If no codes are
present for a system, a "NO X CODE" message (with X being the system, i.e. ECM/PCM, BCM, or SIR) will be displayed. If the communication
line to a component is not operating, a "NO X DATA" message will be displayed, indicating that the BCM could not communicate with that
system.
4.
To view ECM/PCM DATA PARAMETERS, refer to BASIC OPERATION under COMPUTERIZED ENGINE CONTROLS/CADILLAC
PORT FUEL INJECTION/DIAGNOSIS AND TESTING PROCEDURES/TESTING PROCEDURES/ECM/PCM DISPLAYS.
5.
To get out of the diagnostic mode, depress the "RESET" button or turn the ignition switch OFF for 10 seconds. Trouble codes are not erased when
this is done. The temperature setting will reappear in the display panel.
Data Parameters
BD20
The commanded blower voltage is read in volts from -2.9 to 18.0 Volts.
BD21
The coolant temperature is displayed in degrees Celsius (°C) from -40° to 151°C. This value is sent from the PCM to the BCM. If this circuit
malfunctions as determined by the PCM, the PCM will send the BCM a "Failsoft" value for display.
BD22
The commanded air mix door position is displayed in percent (%). A value close to 0% represents a cold air mix and a value close to 100%
represents a warm air mix.
BD23
The actual air mix door position is displayed in percent (%). This value should follow the commanded air mix door position (BD22) except
when the door is commanded beyond its mechanical limits of travel.
BD24
The air delivery mode is displayed as a number from 0 to 9. Each number is a code which represents the following air delivery modes:
0 = MAX A/C
1 = A/C
2 = Bi-Level
3 = Heater/Defrost
4 = Heater
5 = OFF
6 = Normal Purge
7 = Cold Purge
8 = Front Defrost
9 = A/C Purge
BD25
The in-car temperature is displayed in degrees Celsius (°C), from -40 to 102.
BD26
The actual outside temperature is displayed in degrees Celsius (°C), from -40° to 102°. This value represents actual sensor temperature and is
not restricted by the features used to minimize engine heat effects on the customer display value.
BD27
The A/C high side temperature (condenser output) is displayed in degrees Celsius (°C) from -40° to 215°.
BD28
The A/C low side temperature (evaporator input) is displayed in degrees Celsius (°C) from -40° to 102°.
BD32
The sunload temperature is the heat load induced on the vehicle by the sun that is received by the BCM by the sunload temperature sensor.
This is displayed in degrees Celsius (°C) from -40° to 102°.
BD40
The actual fuel level is read in gallons between 0 and 19.0 (the display can read to 25.0). This value represents actual sensor position and is not
restricted by the features used to eliminate fuel slosh affects on the customer display value.
BD42
The dimming pot is displayed in percent (%). A value close to 0% represents maximum dimming and a value close to 100% represents
maximum brightness.
BD43
The twilight delay pot is displayed in percent (%). A value close to 0% represents minimum delay time and a value close to 100% represents
maximum delay time.
BD44
The twilight photocell is displayed in percent (%). A value close to 0% represents daylight and value close to 100% represents darkness.
BD50
The battery voltage is read in volts between 0 and 16.3.
