Input
When troubleshooting a malfunction, the ECM and BCM 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:
BCM:
BD20 The COMMANDED BLOWER VOLTAGE is read in volts from 0 to system voltage.
BD21 The COOLANT TEMPERATURE is displayed in degrees Celsius (~C) from - 40 to 151. This value is sent from the ECM to the BCM. If this circuit malfunctions as determined by the ECM, the ECM 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 10. Each number is a code which represents the following air delivery modes:
0 = Auto - Recirc/MAX A/C
1 = Auto - A/C (vents)
2 = Auto - Bi-Level
3 = Auto - Heater-Def
4 = Auto - Heater
5 = OFF
6 = Normal Purge
7 = Cold (DEF) Purge
8 = Forced/Def
9 = Forced/Heater
10 = Foreed/Bi-Level
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 58. This value represents actual sensor temperature and is not restricted by the features used to minimize engine heat affects on the customer display value.
BD27 The HIGH SIDE TEMPERATURE (condenser output) is displayed in degrees Celsius (~C) from - 40 to 215.
BD28 The LOW SIDE TEMPERATURE (evaporator input) is displayed in degrees Celsius (~C) from - 40 to 93.
BD32 The SUNLOAD TEMPERATURE SENSOR is displayed in degrees Celsius (~C) from - 23 to 102.
BD40 The ACTUAL FUEL LEVEL is read in gallons between 0 and 19.0. 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 25.5.
BD51 The GENERATOR FIELD is displayed in percent (%). A value close to 0% represents minimum regulator on time and a value close to 100% represents maximum regulator on time.
BD60 The VEHICLE SPEED is displayed in miles per hour (MPH) from 0 to 159.
BD61 The ENGINE SPEED is displayed in RPM from 0 to 6375.
BD70 The CRUISE SERVO POSITION is displayed in percent (%) from 0 to 100. A value close to 0% represents rest position and a value close to 100% represents W.O.T.
BD71 The OIL PRESSURE SENSOR is displayed in pressure (PSI) from 0 to 80.
BD98 The IGNITION CYCLE value is the number of times that the ignition has been cycled to "OFF" since a BCM Trouble Code was last detected. After 50 ignition cycles without any malfunction being detected, all BCM codes are cleared.
BD99 The BCM PROM I.D. is displayed as a number, up to four digits long, which can be used to verify that the proper PROM was installed in the BCM.
Input Displays
When troubleshooting a malfunction, the ECM, BCM, or IPC input display can be used to determine if the switched inputs can be properly interpreted. When one of the various input tests is selected, the state of that device is displayed as HI or LO. In general, the HI and LO refer to the input terminal voltage for that circuit. The display also indicates if the input changed state so that the technician could activate or deactivate any listed device and return to the display to see if it changed state. If a change of state occurred, an "X" will appear next to the HI/LO indicator, otherwise a "O" will remain displayed. The "X" will only appear once per selected input, although the HI/LO indication will continue to change as the input changes. Some tests are momentary and the "X" can be used as an indication of a change. The following is a list of ECM, BCM and IPC inputs:
BCM:
BI01 The COURTESY LAMP PANEL SWITCH display is "LO" when courtesy lights are on from switch.
BI02 The PARK LAMP SWITCH display is "LO" when the parklamp switch is in the off position.
BI03 The DRIVER DOOR AJAR SWITCH display is "LO" when the driver's door is ajar.
BI04 The PASSENGER DOOR AJAR SWITCH display is "LO" when the passenger door is ajar.
BI05 The DOOR JAMB SWITCH display is "LO" when the driver's or passenger's door is open.
BI06 The DOOR HANDLE SWITCH display is momentarily "LO" when either outside door handle button is depressed.
BI08 The LOW REFRIGERANT PRESSURE SWITCH display is "LO" when the system is low on refrigerant.
BI09 The WASHER FLUID LEVEL SWITCH display is "LO" when the vehicle is low on washer fluid.
BII0 The LOW COOLANT LEVEL display is "LO" when the engine is low on coolant.
BI16 The KEY IN IGNITION display is "LO" only when the key is in the "LOCK" position. (Cannot be seen as diagnostics do not work with key off, therefore, should always read "HI").
BI19 The LOW VACUUM SWITCH display is "LO" when vacuum supply is low.
BI21 The LOW BRAKE FLUID display is "LO" when brake fluid level is low.
BI22 The PARK BRAKE SWITCH display is "LO" when the parking brake is ON.
BI24 The REVERSE GEAR SWITCH display is "HI" only when the vehicle is in reverse.
BI25 The SEAT BELT SWITCH display is "HI" when the driver's seatbelt is fastened.
BI26 The OIL PRESSURE SWITCH display is "LO" when oil pressure is low.
BI51 The GENERATOR FEEDBACK display is "LO" when there is an GENERATOR problem (or engine not running).
BI71 The CRUISE CONTROL BRAKE SWITCH display is "HI" when the cruise ON/OFF switch is "ON" and the brake pedal is not depressed (free state).
BI75 The CRUISE CONTROL ON/OFF SWITCH display is "HI" when the switch is "ON".
BI76 The CRUISE CONTROL, SET/COAST SWITCH display is "HI" when the cruise ON/OFF switch is "ON" and the set/coast switch is depressed.
BI77 The CRUISE CONTROL RESUME/ACCEL SWITCH display is "HI" when the cruise ON/OFF switch is "ON" and the Resume/Acel switch is depressed.
BI78 The HEADLAMP SWITCH display is "HI" whenever the headlamps are on.
BI79 The HIGH BEAM SWITCH display is "LO" as long as the lever is pulled.
BI82 The TWILIGHT ENABLE SWITCH is "LO" whenever the twilight sentinel is turned on.
Output Displays
When troubleshooting a malfunction, the ECM and BCM output cycling can be used to determine if the output tests can be actuated regardless of the inputs and normal program instructions. Once a test in outputs has been selected, except for ECM IAC, the test will display HI and LO for three seconds in each state to indicate the command and output terminal voltage. A brief summary of each output is provided below:
BCM:
BO00 The NO OUTPUTS display will not display "HI" nor "LO" as this is a resting spot where no outputs will be cycled.
BO01 The CRUISE CONTROL VENT SOLENOID display is "HI" when the vent solenoid is on (energized). The cruise ON/OFF switch must be on for this output to cycle.
BO02 The CRUISE CONTROL VACUUM SOLENOID display is "HI" when the vacuum solenoid is on (energized.) The cruise ON/OFF switch must be on for this output to cycle.
BO03 The RETAINED ACCESSORY POWER (RAP) relays display is "LO" when the relays are on (energized).
BO04 The COURTESY RELAY display is "LO" when the relay is on (energized).
BO05 The TWILIGHT RELAYS display is "LO" when the relays are (energized) fights on.
BO06 The HI/LO BEAM RELAYS display is "LO" when the relays are on (energized) hi beams on.
BO10 The CHIME 1 display is "LO" when the slow chime is on (sounding).
BO11 The CHIME 2 display is "LO" when the intermediate chime is on sounding.