Page 177 of 2305

TEST ACTION APPLICABILITY
4 Turn the ignition off.
Disconnect the Engine Control Module harness connectors.
Check all of the engine control module's power circuits for a short or open condition.
Check all of the engine control module's ground circuits for an open condition.
Were any problems found?All
Ye s!Repair the power/ground circuit(s) as necessary.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 5
5 Turn the ignition off.
Disconnect the Engine Control Module harness connectors.
Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-)
circuit in the Engine Control Module harness connector.
Is the resistance 57 to 63 ohms?All
Ye s!Replace the Engine Control Module in accordance with the
Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No!Repair the CAN C Bus (+)/CAN C Bus (-) circuit(s) for an open.
Perform BODY VERIFICATION TEST - VER 1.
6 Turn the ignition off.
Disconnect the Automatic Temperature Control (ATC) C1 harness connector.
Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-)
circuit in the Automatic Temperature Control (ATC) C1 harness connector.
Is the resistance 57 to 63 ohms?All
Ye s!Replace the Automatic Temperature Control in accordance with
the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No!Repair the CAN C Bus (+)/CAN C Bus (-) circuit(s) for an open.
Perform BODY VERIFICATION TEST - VER 1.
164
HEATING & A/C
NO COMMUNICATION WITH ECM (ACTIVE) ÐContinued
Page 178 of 2305

Symptom:
NO COMMUNICATION WITH IC (ACTIVE)
When Monitored and Set Condition:
NO COMMUNICATION WITH IC (ACTIVE)
When Monitored: With the ignition on.
Set Condition: This DTC will set if the Automatic Temperature Control (ATC) fails to
receive all messages from the Instrument Cluster.
POSSIBLE CAUSES
CAN C BUS CIRCUIT(S) SHORTED OR OPEN
INSTRUMENT CLUSTER DTC(S) PRESENT
INSTRUMENT CLUSTER'S POWER/GROUND CIRCUIT(S) SHORTED OR OPEN
INSTRUMENT CLUSTER
CAN C BUS (+)/CAN C BUS (-) CIRCUIT(S) OPEN TO INSTRUMENT CLUSTER
AUTOMATIC TEMPERATURE CONTROL (ATC)
CAN C BUS (+)/CAN C BUS (-) CIRCUIT(S) OPEN TO AUTOMATIC TEMPERATURE CONTROL
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, read Automatic Temperature Control DTCs.
Does the DRBIIItdisplay: NO COMMUNICATION BUS?All
Ye s!Refer to the Communication category for the related symptom.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 2
2 Turn the ignition on.
With the DRBIIIt, read Instrument Cluster DTCs.
Does the DRBIIItdisplay any DTCs?All
Ye s!Refer to Instrument Cluster category for the related symptom(s).
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 3
3 Turn the ignition on.
With the DRBIIIt, check the TCM and ABS module for the same or similar No
Communication with Instrument Cluster DTC.
Does the DRBIIItdisplay same or similar DTC in TCM & ABS module?All
Ye s!Go To 4
No!Go To 6
165
HEATING & A/C
Page 179 of 2305

TEST ACTION APPLICABILITY
4 Turn the ignition off.
Disconnect the Instrument Cluster harness connectors.
Check all of the instrument cluster's power circuits for a short or open condition.
Check all of the instrument cluster's ground circuits for an open condition.
Were any problems found?All
Ye s!Repair the power/ground circuit(s) as necessary.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 5
5 Turn the ignition off.
Disconnect the Instrument Cluster harness connectors.
Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-)
circuit in the Instrument Cluster harness connector.
Is the resistance 57 to 63 ohms?All
Ye s!Replace the Instrument Cluster in accordance with the Service
Information.
Perform BODY VERIFICATION TEST - VER 1.
No!Repair the CAN C Bus (+)/CAN C Bus (-) circuit(s) for an open.
Perform BODY VERIFICATION TEST - VER 1.
6 Turn the ignition off.
Disconnect the Automatic Temperature Control (ATC) C1 harness connector.
Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-)
circuit in the Automatic Temperature Control (ATC) C1 harness connector.
Is the resistance 57 to 63 ohms?All
Ye s!Replace the Automatic Temperature Control in accordance with
the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No!Repair the CAN C Bus (+)/CAN C Bus (-) circuit(s) for an open.
Perform BODY VERIFICATION TEST - VER 1.
166
HEATING & A/C
NO COMMUNICATION WITH IC (ACTIVE) ÐContinued
Page 180 of 2305

Symptom:
RECIRC AIR SOLENOID CONTROL HIGH OR OPEN (ACTIVE)
POSSIBLE CAUSES
RECIRCULATED AIR SOLENOID VALVE
RECIRCULATED AIR SOLENOID VALVE CONTROL CIRCUIT SHORTED TO VOLTAGE
AUTOMATIC TEMPERATURE CONTROL (ATC)
RECIRCULATED AIR SOLENOID VALVE CONTROL CIRCUIT OPEN
GROUND CIRCUIT OPEN
AUTOMATIC TEMPERATURE CONTROL (ATC)
TEST ACTION APPLICABILITY
1 Turn the ignition on.
Press the Air Recirculation switch off.
Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Recirculated Air Solenoid Valve harness connector.
Connect a 12-volt test light between the Recirculated Air Solenoid Valve Control
circuit and the Ground circuit in the Recirculated Air Solenoid harness connector.
Turn the ignition on. The test light should operate as follows:
With the Air Recirculation switch off, the test light should not illuminate.
Press the Air Recirculation switch on. The test light should illuminate brightly.
Does the test light function as specified?All
Yes, Light Only Illuminates w/Recirc On
Replace the Recirculated Air Solenoid Valve in accordance with
the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No, Light Illuminates w/Recirc Off
Go To 2
No, Light Will Not Illuminate
Go To 3
2 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Recirculated Air Solenoid Valve harness connector.
Disconnect the Automatic Temperature Control (ATC) C1 harness connector.
Turn the ignition on.
Measure the voltage of the Recirculated Air Solenoid Valve Control circuit.
Is the voltage above 0.2 volts?All
Ye s!Repair the Recirculated Air Solenoid Valve Control circuit for a
short to voltage.
Perform BODY VERIFICATION TEST - VER 1.
No!Replace the Automatic Temperature Control (ATC) in accordance
with the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
167
HEATING & A/C
Page 181 of 2305

TEST ACTION APPLICABILITY
3 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Automatic Temperature Control (ATC) C1 harness connector.
Disconnect the Recirculated Air Solenoid Valve harness connector.
Measure the resistance of the Recirculated Air Solenoid Valve Control circuit
between the Automatic Temperature Control (ATC) C1 harness connector and the
Recirculated Air Solenoid Valve harness connector.
Is the resistance below 5.0 ohms?All
Ye s!Go To 4
No!Repair the Recirculated Air Solenoid Valve Control circuit for an
open.
Perform BODY VERIFICATION TEST - VER 1.
4 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Recirculated Air Solenoid Valve harness connector.
Measure the resistance between ground and the Ground circuit.
Is the resistance below 5.0 ohms?All
Ye s!Replace the Automatic Temperature Control (ATC) in accordance
with the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No!Repair the Ground circuit for an open.
Perform BODY VERIFICATION TEST - VER 1.
168
HEATING & A/C
RECIRC AIR SOLENOID CONTROL HIGH OR OPEN (ACTIVE) ÐContinued
Page 182 of 2305

Symptom:
RECIRC AIR SOLENOID CONTROL SHORTED LOW (ACTIVE)
POSSIBLE CAUSES
RECIRCULATED AIR SOLENOID VALVE CONTROL CIRCUIT SHORTED TO GROUND
RECIRCULATED AIR SOLENOID VALVE CONTROL CIRCUIT SHORTED TO GROUND CIRCUIT
RECIRCULATED AIR SOLENOID VALVE CONTROL CIRCUIT SHORTED TO SENSOR GROUND
CIRCUIT
AUTOMATIC TEMPERATURE CONTROL (ATC)
RECIRCULATED AIR SOLENOID VALVE
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Disconnect the Recirculated Air Solenoid Valve harness connector.
Disconnect the Automatic Temperature Control (ATC) C1 harness connector.
Measure the resistance between ground and the Recirculated Air Solenoid Valve
Control circuit.
Is the resistance below 10k ohms?All
Ye s!Repair the Recirculated Air Solenoid Valve Control circuit for a
short to ground.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 2
2 Turn the ignition off.
Disconnect the Recirculated Air Solenoid Valve harness connector.
Disconnect the Automatic Temperature Control (ATC) C1 harness connector.
Measure the resistance between the Recirculated Air Solenoid Valve Control circuit
and the Ground circuit in the Automatic Temperature Control C1 harness connector.
Is the resistance below 10k ohms?All
Ye s!Repair the Recirculated Air Solenoid Valve Control circuit for a
short to the Ground circuit.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 3
3 Turn the ignition off.
Disconnect the Recirculated Air Solenoid Valve harness connector.
Disconnect the Automatic Temperature Control (ATC) C1 harness connector.
Measure the resistance between the Recirculated Air Solenoid Valve Control circuit
and the Sensor Ground circuit in the Automatic Temperature Control C1 harness
connector.
Is the resistance below 10k ohms?All
Ye s!Repair the Recirculated Air Solenoid Valve Control circuit for a
short to the Sensor Ground circuit.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 4
169
HEATING & A/C
Page 183 of 2305

TEST ACTION APPLICABILITY
4 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Reconnect the Automatic Temperature Control (ATC) C1 harness connector.
Disconnect the Recirculated Air Solenoid Valve harness connector.
Turn the ignition on.
Press the Air Recirculation switch off.
Turn the ignition off.
Connect a 12-volt test light between the Recirculated Air Solenoid Valve Control
circuit and the Ground circuit in the Recirculated Air Solenoid harness connector.
Turn the ignition on. The test light should operate as follows:
With the Air Recirculation switch off, the test light should not illuminate.
Press the Air Recirculation switch on. The test light should illuminate brightly.
Does the test light function as specified?All
Ye s!Replace the Recirculated Air Solenoid Valve in accordance with
the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
No!Replace the Automatic Temperature Control (ATC) in accordance
with the Service Information.
Perform BODY VERIFICATION TEST - VER 1.
170
HEATING & A/C
RECIRC AIR SOLENOID CONTROL SHORTED LOW (ACTIVE) ÐContinued
Page 184 of 2305

Symptom:
REFRIG PRESS SENSOR HIGH OR OPEN (ACTIVE)
POSSIBLE CAUSES
5 VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
REFRIGERANT PRESSURE SENSOR FEEDBACK CIRCUIT SHORTED TO VOLTAGE
5 VOLT SUPPLY CKT SHORTED TO REFRIGERANT PRESSURE SENSOR FEEDBACK CKT
AUTOMATIC TEMPERATURE CONTROL (ATC)
5 VOLT SUPPLY CIRCUIT OPEN
REFRIGERANT PRESSURE SENSOR FEEDBACK CIRCUIT OPEN
SENSOR GROUND CIRCUIT OPEN
REFRIGERANT PRESSURE SENSOR
TEST ACTION APPLICABILITY
1 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Automatic Temperature Control (ATC) C1 harness connector.
Turn the ignition on.
Measure the voltage of the 5 Volt Supply circuit.
Is the voltage above 0.2 volts?All
Ye s!Repair the 5 Volt Supply circuit for a short to voltage.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 2
2 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Automatic Temperature Control (ATC) C1 harness connector.
Turn the ignition on.
Measure the voltage of the Refrigerant Pressure Sensor Feedback circuit.
Is the voltage above 0.2 volts?All
Ye s!Repair the Refrigerant Pressure Sensor Feedback circuit for a
short to voltage.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 3
3 Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
Disconnect the Refrigerant Pressure Sensor harness connector.
Disconnect the Automatic Temperature Control (ATC) C1 harness connector.
Measure the resistance between the 5 Volt Supply circuit and the Refrigerant
Pressure Sensor Feedback circuit.
Is the resistance below 10k ohms?All
Ye s!Repair the 5 Volt Supply circuit for a short to the Refrigerant
Pressure Sensor Feedback circuit.
Perform BODY VERIFICATION TEST - VER 1.
No!Go To 4
171
HEATING & A/C