B1031

B1031-EVAPORATOR TEMPERATURE SENSOR CIRCUIT LOW





For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams.

- When Monitored:
With the ignition on.

- Set Condition:
If the Evaporator Temperature Sensor input is out of range toward the low voltage threshold, (A/D counts reach low threshold of 3). This DTC has a maturing time of 5 seconds and a de-maturing time of 10 seconds. If the DTCs status changes from active to stored it will stay in memory for 100 ignition cycles.





NOTE: This DTC must be active for the results of this test to be valid. Do not perform this test if this DTC is stored. Perform the HVAC System Test for stored DTC test procedures. HVAC System Test

1. CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT VOLTAGE WITH THE SENSOR DISCONNECTED




1. Turn the ignition off.
2. Disconnect the Evaporator Temperature Sensor harness connector.
3. Turn the ignition on.
4. With the scan tool in Data Display, read the Evaporator Temperature Sensor voltage.

Is the voltage 4.9 volts or greater?

Yes

- Replace the Evaporator Temperature Sensor.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 2

2. CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND




1. Turn the ignition off.
2. Disconnect the A/C Heater Control C1 harness connector.
3. Measure the resistance of the (C21) Evaporator Temperature Sensor Signal circuit between ground and the A/C Heater Control C1 harness connector.

Is the resistance below 10k Ohms?

Yes

- Repair the (C21) Evaporator Temperature Sensor Signal circuit for a short to ground.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 3

3. CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO (C121) SENSOR GROUND CIRCUIT




1. Measure the resistance between the (C21) Evaporator Temperature Sensor Signal circuit and the (C121) Sensor Ground circuit in the A/C Heater Control C1 harness connector.

Is the resistance below 10k Ohms?

Yes

- Repair the (C21) Evaporator Temperature Sensor Signal circuit for a short to the (C121) Sensor Ground circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Replace the A/C Heater Control.
- Perform the BODY VERIFICATION TEST. Body Verification Test.