DIAGNOSIS AND TESTING
- B1001-A/C SWITCH REQUEST INPUT CIRCUIT LOW (CCN)
- B1002-A/C SWITCH REQUEST INPUT CIRCUIT HIGH (CCN)
- B1031-EVAPORATOR FIN TEMPERATURE SENSOR CIRCUIT LOW (CCN)
- B1032-EVAPORATOR FIN TEMPERATURE SENSOR CIRCUIT HIGH (CCN)
- B10C1-A/C SELECT SWITCH STUCK (CCN)
B1001-A/C SWITCH REQUEST INPUT CIRCUIT LOW (CCN)
For a complete wiring diagram Refer to Section 8W.
Theory of Operation
The A/C mode switch input changes when the switch is pushed down. An active DTC indicates that the switch is stuck in a pushed position. A stored DTC indicates that the switch was stuck in a pushed position for more than two minutes, but has since returned to its normal state.
- When Monitored:
With the ignition on.
- Set Condition:
If the A/C mode switch is stuck in a pushed position for more than two minutes. This DTC has a maturing time of two minutes and a de-maturing time of two seconds. If the DTC's status changes from active to stored it will stay in memory for 100 ignition cycles.
| Possible Causes |
| OBJECT HOLDING SWITCH IN A PUSHED POSITION |
| A/C HEATER CONTROL |
Diagnostic Test
1. VERIFY B1001–A/C SWITCH REQUEST INPUT CIRCUIT LOW IS ACTIVETurn the ignition on.
With the scan tool, erase DTCs.
Turn the ignition off, wait 10 seconds, and turn the ignition on.
With the scan tool, read DTCs.
Does the scan tool display this DTC as active?
Yes
- Go To 2
No
- Check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched, and partially broken wires. Also, inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals. Repair as necessary.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
2. INSPECT FOR OBJECT HOLDING SWITCH IN A PUSHED POSITION
Inspect the A/C Heater Control for an object holding the switch in a pushed position. If present, remove the object.
Turn the ignition on.
With the scan tool, erase HVAC DTCs.
Turn the ignition off, wait 10 seconds, and then turn the ignition on.
Wait two minutes, then with the scan tool, read HVAC DTCs.
Does the scan tool display this DTC as active?
Yes
- Replace the A/C Heater Control in accordance with the service information.
- Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
B1002-A/C SWITCH REQUEST INPUT CIRCUIT HIGH (CCN)
For a complete wiring diagram Refer to Section 8W.
- When Monitored:
With the ignition on.
- Set Condition:
If the Instrument Cluster (CCN) detects voltage above 4.5 volts for 10 seconds on the (C105) HVAC MUX Control circuit.
| Possible Causes |
| (C105) HVAC MUX CONTROL CIRCUIT SHORTED TO VOLTAGE |
| (C105) HVAC MUX CONTROL CIRCUIT OPEN |
| (C955) HVAC MUX RETURN CIRCUIT OPEN |
| A/C HEATER CONTROL |
| INSTRUMENT CLUSTER (CCN) |
Diagnostic Test
1. VERIFY DTC B1002–A/C SWITCH REQUEST INPUT CIRCUIT HIGH IS ACTIVETurn the ignition on.
With the scan tool, erase DTCs.
Turn the ignition off, wait 10 seconds, and turn the ignition on.
With the scan tool, read DTCs.
Does the scan tool display this DTC as active?
Yes
- Go To 2
No
- Check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched, and partially broken wires. Also, inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals. Repair as necessary.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
2. CHECK THE (C105) HVAC MUX CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
Turn the ignition off.
Disconnect the Instrument Cluster C2 harness connector.
Disconnect the HVAC Control Head C1 harness connector.
Turn the ignition on.
Measure the voltage of the (C105) HVAC MUX Control circuit.
Is there any voltage present?
Yes
- Repair the (C105) HVAC MUX Control circuit for a short to voltage.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Go To3
3. CHECK THE (C105) HVAC MUX CONTROL CIRCUIT FOR AN OPEN
Turn the ignition off.
Measure the resistance of the (C105) HVAC MUX Control circuit between the A/C Heater Control C1 harness connector and the Instrument Cluster C2 harness connector.
Does the ohm meter read open circuit?
Yes
- Repair the (C105) HVAC MUX Control circuit for an open.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Go To5
4. CHECK THE (C955) HVAC MUX RETURN CIRCUIT FOR AN OPEN
Measure the resistance of the (C955) HVAC MUX Return circuit between the A/C Heater Control C1 harness connector and the Instrument Cluster C2 harness connector.
Does the ohm meter read open circuit?
Yes
- Repair the (C955) HVAC MUX Return circuit for an open.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Go To5
5. CHECK THE OPERATION OF THE INSTRUMENT CLUSTER (CCN)
Reconnect the Instrument Cluster (CCN) harness connector.
Turn the ignition on.
With the scan tool, read DTCs.
Does the scan tool display this DTC as active?
Yes
- Replace the Instrument Cluster (CCN) in accordance with the service information.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Replace the HVAC control head in accordance with the service information.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
B1031-EVAPORATOR FIN TEMPERATURE SENSOR CIRCUIT LOW (CCN)
For a complete wiring diagram Refer to Section 8W.
- When Monitored:
With the ignition on.
- Set Condition:
If the Evaporator Temperature Sensor input is out of range toward the low voltage threshold.
| Possible Causes |
| (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT SHORTED TO GROUND |
| EVAPORATOR TEMPERATURE SENSOR |
| INSTRUMENT CLUSTER (CCN) |
Diagnostic Test
1. VERIFY B1031–EVAPORATOR FIN TEMPERATURE SENSOR CIRCUIT LOW IS ACTIVETurn the ignition on.
With the scan tool, erase DTCs.
Turn the ignition off, wait 10 seconds, and turn the ignition on.
With the scan tool, read DTCs.
Does the scan tool display this DTC as active?
Yes
- Go To 2
No
- Check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched, and partially broken wires. Also, inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals. Repair as necessary.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
2. CHECK FOR DTC WITH THE EVAPORATOR TEMPERATURE SENSOR HARNESS CONNECTOR DISCONNECTED
Turn the ignition off.
Disconnect the Evaporator Temperature Sensor harness connector.
Turn the ignition on.
With the scan tool, erase DTCs.
Turn the ignition off, wait 10 seconds, and turn the ignition on.
With the scan tool, read DTCs.
Does the scan tool display this DTC as active?
Yes
- Go To 3.
No
- Replace the Evaporator Temperature Sensor in accordance with the service information.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
3. CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND
Turn the ignition off.
Disconnect the Instrument Cluster (CCN) C3 harness connector.
Measure the resistance between ground and the (C21) Evaporator Temperature Sensor Signal circuit and ground.
Does the ohm meter read open circuit?
Yes
- Replace the Instrument Cluster (CCN) in accordance with the service information.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Repair the (C21) Evaporator Temperature Sensor Signal circuit for a short to ground.
B1032-EVAPORATOR FIN TEMPERATURE SENSOR CIRCUIT HIGH (CCN)
For a complete wiring diagram Refer to Section 8W.
- When Monitored:
With the ignition on.
- Set Condition:
If the Evaporator Temperature Sensor input is out of range toward the high voltage threshold.
| Possible Causes |
| (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE |
| (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT OPEN |
| (C121) SENSOR GROUND CIRCUIT OPEN |
| EVAPORATOR TEMPERATURE SENSOR |
| INSTRUMENT CLUSTER (CCN) |
Diagnostic Test
1. VERIFY B1032–EVAPORATOR FIN TEMPERATURE SENSOR CIRCUIT HIGH IS ACTIVETurn the ignition on.
With the scan tool, erase DTCs.
Turn the ignition off, wait 10 seconds, and turn the ignition on.
With the scan tool, read DTCs.
Does the scan tool display this DTC as active?
Yes
- Go To 2
No
- Check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched, and partially broken wires. Also, inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals. Repair as necessary.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
2. CHECK FOR DTC WITH THE EVAPORATOR TEMPERATURE SENSOR HARNESS CONNECTOR DISCONNECTED
Turn the ignition off.
Disconnect the Evaporator Temperature Sensor harness connector.
Turn the ignition on.
With the scan tool, erase DTCs.
Turn the ignition off, wait 10 seconds, and turn the ignition on.
With the scan tool, read DTCs.
Does the scan tool display this DTC as active?
Yes
- Go To 3.
No
- Replace the Evaporator Temperature Sensor in accordance with the service information.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
3. CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR AN OPEN
Disconnect the Instrument Cluster (CCN) C3 harness connector.
Measure the resistance of the (C21) Evaporator Temperature Sensor Signal circuit between the Instrument Cluster (CCN) C3 harness connector and the Evaporator Temperature Sensor harness connector.
Does the ohm meter read open circuit?
Yes
- Repair the (C21) Evaporator Temperature Sensor Signal circuit for an open.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Go To 5.
4. CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR SHORT TO VOLTAGE
Using a volt meter check for voltage on the (C21) Evaporator Temperature Sensor Signal circuit.
Does the volt meter read any voltage?
Yes
- Repair the (C21) Evaporator Temperature Sensor Signal circuit for a short to voltage.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Go To 5.
5. CHECK (C121) SENSOR GROUND CIRCUIT FOR AN OPEN
Measure the resistance of the (C121) Sensor Ground circuit between the Instrument Cluster (CCN) C3 harness connector and the Evaporator Temperature Sensor harness connector.
Does the ohm meter read open circuit?
Yes
- Replace the Instrument Cluster (CCN) in accordance with the service information.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Repair the (C121) Sensor Ground circuit for an open.
- Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
B10C1-A/C SELECT SWITCH STUCK (CCN)
For a complete wiring diagram Refer to Section 8W.
- When Monitored:
With the ignition on.
- Set Condition:
If the Instrument Cluster (CCN) detects that the A/C mode switch stays in a pushed position for more than 5 seconds.
| Possible Causes |
| DTC B1001 OR B1002 ACTIVE IN THE CCN |
| OBJECT HOLDING A/C MODE SWITCH IN A PUSHED POSITION |
| SUBSTANCE CAUSING A/C MODE SWITCH TO GET STUCK IN A PUSHED POSITION |
| A/C HEATER CONTROL |
Diagnostic Test
1. CHECK FOR ACTIVE DTC B1001 OR B1002 IN THE CCNTurn the ignition on.
With the scan tool, read CCN DTCs.
Does the scan tool display active: B1001 or B1002?
Yes
- Diagnose and repair the DTC. Refer to the Table of Contents in this Section.
No
- Go To 2
2. INSPECT THE A/C HEATER CONTROL FOR DAMAGE
Turn the ignition off.
Inspect the A/C Heater Control for damage.
Is the A/C Heater Control damaged?
Yes
- Replace the A/C Heater Control in accordance with the service information.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Go To 3
3. INSPECT FOR OBJECT OR SUBSTANCE CAUSING THE A/C MODE SWITCH TO STAY OR STICK IN A PUSHED POSITION
Inspect the A/C Heater Control for anything that would cause the A/C mode switch to stay or stick in a pushed position.
Is anything present that would cause the A/C mode switch to stay or stick in a pushed position?
Yes
- Repair as necessary.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Go To 4
4. CHECK THE A/C MODE SWITCH & STATUS INDICATOR FUNCTION
Start the engine.
Turn the blower control on.
Press the A/C mode switch on and off several times while observing the A/C status indicator.
Does the A/C status indicator turn on and off?
Yes
- Go To 5
No
- Replace the A/C Heater Control in accordance with the service information.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
5. VERIFY THAT DTC B10C1–A/C SELECT SWITCH STUCK IS STILL ACTIVE
Turn the ignition on.
With the scan tool, erase CCN DTCs.
Turn the ignition off, wait 10 seconds, and turn the ignition on.
With the scan tool, read CCN DTCs.
Does the scan tool display active: B10C1–A/C SELECT SWITCH STUCK?
Yes
- Replace the A/C Heater Control in accordance with the service information.
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).
No
- Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).