GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 Sonoma Pickup - 2WD 🢒 DTC 🢒 DTC B0165 Pass Compart Temp Sensor 1 Circuit Low

Object Number: 394198 Size: MF
Handling ESD Sensitive Parts Notice
HVAC Components
Cell 68: ECC Module and Temperature Sensors
Cell 68: ECC Module and Temperature Sensors

Circuit Description

The inside air temperature sensor is a thermistor used in order to control the signal voltage in the electronic climate control (ECC) module. The ECC module supplies a reference voltage (about 5 volts) on CKT 734 to the sensor. When the inside air temperature is cold, the thermistor resistance is high. Therefore, the ECC module will receive a high voltage input. If the outside air temperature is hot, the thermistor resistance is low. Therefore, the ECC module will receive a low signal voltage input. Refer to Sensor Resistance Table .

Conditions for Setting the DTC

When the ignition is ON, the ECC module will detect the DTC B0165 any time that CKT 734 is at or near zero voltage.

Action Taken When the DTC Sets

The ECC module will use a default value of 23.8°C (75°F) or 88 A/D counts until the fault is cleared.

Conditions for Clearing the MIL/DTC

This fault will clear as soon as the fault goes away or has been repaired. The system will then return to normal operation. History DTCs may only be cleared by removing and restoring B+ or by using the scan tool.

Diagnostic Aids
    • The ECC module may set class 2 lost communication DTCs when the body control module (BCM) or the vehicle control module (VCM) is being reprogrammed After reprogramming, inspect for DTCs in the ECC module. Clear any history U DTCs, then resume diagnostics.
    • Visually inspect the sensor connector and harness for corrosion and damage. The resistance value of the sensor must be 300-170,000 ohms. If the resistance is not within specifications, replace the sensor.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step measures the resistance of the inside air temperature sensor.

    2.

  2. This step inspects for a short to ground in CKT 734 (DK GRN).

    3.

  3. This step inspects for intermittents and tests for a malfunctioning ECC module.

    4.

  4. This step repairs the short to ground in CKT 734 (DK GRN).

    5.

  5. This step replaces a defective inside air temperature sensor.

    6.

  6. This step replaces a defective ECC module.

Step

Action

Value(s)

Yes

No

1

Did you perform the Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check

2

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the inside air temperature sensor.
  3. Measure the resistance between the inside air temperature sensor terminal A and terminal D.
  4. Compare the reading to the temperature/resistance table. Refer to Sensor Resistance Table .

Is the resistance within the range specified in the table?

--

Go to Step 3

Go to Step 6

3

  1. Disconnect the ECC module.
  2. Inspect for a short to ground in CKT 734 (DK GRN) at terminal D1 of the ECC module harness connector.

Is continuity present?

--

Go to Step 5

Go to Step 4

4

  1. Reconnect the inside air temperature sensor.
  2. Reconnect the ECC module.
  3. Turn the ignition switch to the ON position.
  4. Clear any ECC module DTCs.

Does the DTC reset?

--

Go to Step 7

Go to Intermittents and Poor Connections Diagnosis in Wiring Systems

5

Repair the short to ground in CKT 734 (DK GRN).

Is the repair complete?

--

Go to Diagnostic System Check

--

6

Replace the inside air temperature sensor. Refer to Inside Air Temperature Sensor Replacement .

Is the replacement complete?

--

Go to Diagnostic System Check

--

7

Replace the ECC module. Refer to Control Assembly Replacement .

Is the replacement complete?

--

Go to Diagnostic System Check

--