GMC chevrolet camaro 2000 Service Manual page 212

HVAC
Diagnostic Information and Procedures
A Dia.gnostic Starting Point
Begin the system diagnosis by reviewing the system
Description and Operation. Reviewing the Description
and Operation information will help you determine
the correct symptom diagnostic procedure when
a malfunction exists. Reviewing the Description and
Operation information will also help you determine
if the condition described by the customer is normal
operation. Refer to A Diagnostic System Check
in order to identify the correct procedure for diagnosing
the system and where the procedure is located.
HVAC Systems - Manual 1-115
A Diagnostic System Check
Test Description
The number(s) below refer to the step number(s) on
the diagnostic table.
2. Lack of communication may be due to a partial
malfunction of the class 2 serial data circuit or
due to a total malfunction of the class 2 serial data
circuit. The specified procedure will determine
the particular condition.
4. The presence of DTCs which begin with "U"
indicate some of the modules are not
communicating.
A Diagnostic System Check
Step Action Yes No
Install a scan tool. Go to Scan Tool
1
Does the scan tool power up?
Does Not Power Up
in Data Link
Go to Step2 Communications
1. Turn ON the ignition, with the engine OFF.
Go to Scan Tool
2. Attempt to establish communication with each module on the
Does Not
Communicate
2
class 2 circuit serial data circuit. (If using a Tech 2, obtain this
w!Class 2 Data Line
information using the Class 2 Message Monitor feature.)
in Data Link
Does the scan tool communicate with the modules?
Go to Step 3 Communications
1. Select the Display DTCs function for each module. (If using a
Tech 2, use the Class 2 DTC Check feature in order to
determine which modules do have DTCs set.)
3
2. Record all of the displayed DTCs, the DTC status, and the
Go to Symptoms in
module which set the DTC.
HV AC Systems -
Does the scan tool display any DTCs?
Go to Step 4 Manual.
Does the scan tool display any DTCs which begin with a "U"?
Go to Scan Tool
4
Does the scan tool display any PCM DTCs?
5
Symptoms
Important: Review the system operation in order to
familiarize yourself with the system functions. Refer to
Control Assembly Description (Pontiac) for Pontiac
or Control Assembly Description (Chevrolet) for
Chevrolet.
Visual/Physical Inspection
• Inspect for aftermarket devices which could affect
the operation of the HV AC System. Refer to
Checking Aftermarket Accessories
• Inspect the easily accessible or visible system
components for obvious damage or conditions
which could cause the symptom.
Does Not
Communicate
w!Class 2 Data Line
in Data Link
Communications Go to Step 5
Go to Diagnostic
Trouble Code (OTC)
List/Type in Engine
Controls - 3.8 L and
Diagnostic Trouble
Code (OTC) Go to Symptoms in
List/Type in Engine
HV AC Systems -
Controls - 5.7
L.
Manual.
Intermittent
Faulty electrical connections or wiring may be the
cause of intermittent conditions. Refer to Testing for
Intermittent and Poor Connections
Symptom list
Refer to a symptom diagnostic procedure from the
following list in order to diagnose the symptom:
.. Blower Motor Inoperative at Any Speed
" Blower Motor Operates at High Speed Only
s
Blower Motor Inoperative in One Speed Only
(High Speed Operates Normally)
o
Blower Motor High Speed Inoperative