DTC P0538. Chevrolet Joy 2008

For 1990-2009 cars

### Circuit Description

A semiconductor which resistance is noticeably changed as the change of temperature. When the refrigerant temperature of the evaporator drops to 5°C (41°F) and below, the evaporator cores get stuck with frost or ice, reducing the airflow, lowering the cooling capacity. The thermistor is a sensor which is used to prevent from frosting or icing. The thermistor is installed on the evaporator.

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0538 A/C Evaporator Temperature Sensor High

### Conditions for Running the DTC

• | Engine is running.

• | A/C switch is ON.

• | Engine coolant temperature (ECT) is higher than 39.75°C (103.55°F).

• | A/C relay is ON for more than 131 seconds.

### Conditions for Setting the DTC

Evaporator temperature sensor signal is higher than 4.9 V (0.8L) or 4.98 V (1.0L).

### Action Taken When the DTC Sets

• | The Malfunction Indicator Lamp (MIL) will not illuminate.

• | The ECM will record operating conditions at the time the diagnostic fails. This information will be stored Failure Records buffers.

### Conditions for Clearing the MIL/DTC

• | A history DTC will clear after 40 warm-up cycles without a fault.

• | DTC(s) can be cleared by using the scan tool.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: HVAC Schematics
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle

2

1. Turn the ignition switch to LOCK.
2. Disconnect the evaporator temperature sensor.
3. Measure the resistance between evaporator temperature sensor terminals 1 and 2.

Is the resistance within the specified value?

0ohms

Go to Step 7

Go to Step 3

3

1. Turn the ignition switch to OFF.
2. Check for an open, a short to ground, or a short to battery in the signal circuit, at terminal 2 in the sensor harness connector.

Did you find the problem?

--

Go to Step 4

Go to Step 5

4 | Repair the wire or the connector between the terminal 46 (0.8L)/49 (1.0L) of ECM and A/C compressor relay terminal 2. Is the repair complete? | -- | Go to Step 9 | --

5

1. Disconnect the ECM.
2. Check for an open, a short to ground, or a short to battery in the low reference circuit, at terminal 1 in the sensor harness connector.

Did you find the problem?

--

Go to Step 6

Go to Step 8

6 | Repair the wire or the connector between the ECM wiring connector terminal 46 (0.8L)/49 (1.0L) and evaporator temperature sensor terminal 2. Is the repair complete? | -- | Go to Step 9 | --
7 | Replace the evaporator temperature sensor. Is the replacement complete? | -- | Go to Step 9 | --
8 | Replace the ECM. Is the repair complete? | -- | Go to Step 9 | --

9

1. Using the scan tool, clear the Diagnostic Trouble Codes (DTCs).
2. Start the engine and idle at normal operating temperature.
3. Operate the vehicle within the conditions for setting this DTC as specified in the supporting text.

Does the scan tool indicate that this diagnostic has run and passed?

--

Go to Step 10

Go to Step 2

10 | Check if any additional DTCs are set. Are any DTCs displayed that have not been diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List - Vehicle | --