Without Scan Tool

Diagnostic Trouble Codes can be accessed thru the H-AC Control Panel.


CURRENT AND HISTORY DIAGNOSTIC TROUBLE CODES
If the ACAC system detects an error within the HVAC system, a current and history diagnostic trouble code (DTC) will be set. Once the failure is no longer detected, the DTC will be stored only as history trouble code. A two-digit code is a current DTC and the same two-digit code preceded by a "1" is a history DTC. History codes will be stored for 199 ignition cycles. When the counter gets to 199, all history trouble codes will be cleared and the counter will be set back to zero. There will not be any indication to the operator that a failure has been detected or that a current or history trouble code is stored in the H-A/C control memory unless the self-diagnostic mode is entered. If an HVAC DTC is set, the H-A/C control will use a "default value" until the DTC has been cleared or repaired.

TO ENTER THE "ACAC DIAGNOSTIC SYSTEM CHECK"
To enter the "ACAC Diagnostic System Check," press the "TEMP" up switch and the "OFF" switch on the control panel at the same time. Upon entry, a segment check will be performed and then the graphic display will show pointer number "-00". If the compressor clutch is being requested, the "EXT TEMP" graphics will be displayed. The fan up and fan down switch can be used to increase and decrease the pointer number. The "MIDDLE" switch can be used to change from pointer number -02 to DTC or parameter values for pointers "05-31."

TO DISPLAY HVAC DTCS
To display HVAC DTCs. select pointer number "-02". and press the "MIDDLE" switch. At this time any current and history trouble codes will be displayed. A failure indicates that the control has detected an open, short to ground or faulty component in that circuit. While that failure is detected, the control will use a default value. When the graphic display is displaying numbers 200 to 299, they appear as numbers 100 through 199 with a "-" in front of them. For example. the value of 200 would be displayed as "-100."

CLEARING DIAGNOSTIC TROUBLE CODES
HVAC DTCs can he cleared from H-A/C control by pressing the "OFF" button while in diagnostic pointer number "-02" while the HVAC DTCs are displaying.

To exit the self-diagnostic mode, press the AUTO" switch.