HVAC Diagnostic Mode
Thread Starter
Instructor
Joined: Jan 2005
Posts: 120
Likes: 0
From: Fountain Colorado
HVAC Diagnostic Mode
How do I enter the hvac diagnostic mode on an 88 coupe? My door actuator motor won't swing to heat, but it will move to cool if I manually turn the motor to what would be a heat position and turn the temp back down to 60. A friend of mine is letting me use his service manual for an 87. But I don't think the way you get into the diagnostic mode is the same for both years. Defrost and manual up fan button. Thanks in advance.
Brian
Brian
Melting Slicks
Joined: Aug 1999
Posts: 2,240
Likes: 42
From: Baltimore, MD USA
When a code has been stored the EXT TEMP indicator will flash.
To enter diag. mode and read a code if there is one,
Press and hold the EXT Temp. button while pressing and releasing the AUTO button.
A mode number will appear in the display.
The mode you want to examine is -08.
Advance the display to -08 by repeatedly pressing the
WARM button.
Once you get to mode -08, the diagnostic code can be displayed by pressing the COOL button.
Here are the codes than can be stored.
00 no faults
01 Air Mix Valve Acuator Feedback open
02 Outside Temp. Sensor Open
04 Outside Temp. Sensor Shorted
08 In Car Temp. Sensor Open
16 In Car Temp. Sensor Shorted
To enter diag. mode and read a code if there is one,
Press and hold the EXT Temp. button while pressing and releasing the AUTO button.
A mode number will appear in the display.
The mode you want to examine is -08.
Advance the display to -08 by repeatedly pressing the
WARM button.
Once you get to mode -08, the diagnostic code can be displayed by pressing the COOL button.
Here are the codes than can be stored.
00 no faults
01 Air Mix Valve Acuator Feedback open
02 Outside Temp. Sensor Open
04 Outside Temp. Sensor Shorted
08 In Car Temp. Sensor Open
16 In Car Temp. Sensor Shorted
