Circuit Description
The air conditiong (A/C) evaporator temperature sensor is a variable resistor that measures the temperature of the evaporator. The A/C evaporator temperature sensor has a signal circuit and a low reference circuit. The engine control module (ECM) supplies 5 volts to the signal circuit and a ground for the low reference circuit. If the ECM detects a high signal voltage, this DTC sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1536 Air Conditioning (A/C) Evaporator Temperature Sensor Circuit High
Conditions for Running the DTC
| • | The ignition is ON or the engine is operating. |
| • | DTC P1536 runs continuously once the above condition is met. |
Conditions for Setting the DTC
The ECM detects a high voltage condition for more the 1 second.
Action Taken When the DTC Sets - European Emissions
| • | The ECM will not illuminate the malfunction indicator lamp (MIL). |
| • | A history DTCs is stored. |
| • | The ECM will record operating conditions at the time the diagnostic fails. This information will be stored Failure Records. |
| • | The A/C compressor operation will be disabled while the low voltage indication exists. |
Action Taken When the DTC Sets - Non European Emissions
The malfunction indicator lamp (MIL) will illuminate.
Conditions for Clearing the MIL/DTC - European Emissions
| • | The MIL will turn OFF after 4 consecutive ignition cycles in which the diagnostic runs without a fault. |
| • | A history DTC will clear after 40 consecutive warm-up cycles without a fault. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnect the ECM battery feed for 10 seconds. |
Conditions for Clearing the MIL/DTC - Non European Emissions
| • | The MIL will turn OFF when the diagnostic runs and passes. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnect the ECM battery feed for 10 seconds. |
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: HVAC Schematics Connect End View Reference: HVAC Connector End Views | ||||||||||||
1 | Did you perform the Diagnostic System Check - HVAC System? | -- | Go to Step 2 | |||||||||
2 |
Did DTC P1536 fail this ignition? | -- | Go to Step 4 | Go to Step 3 | ||||||||
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | |||||||||
4 |
Is the voltage within the specified range? | 4.8-5.2 V | Go to Step 5 | Go to Step 6 | ||||||||
5 | Probe the low reference circuit of the A/C evaporator temperature sensor with a DMM connected to battery voltage. Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 7 | ||||||||
6 | Test the signal circuit of the A/C evaporator temperature sensor for one of the following conditions:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9 | ||||||||
7 | Test the low reference circuit of the A/C evaporator temperature sensor for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9 | ||||||||
8 | Test for an intermittent and for a poor connection at the A/C evaporator temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 10 | ||||||||
9 | Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 11 | ||||||||
10 | Replace the A/C evaporator temperature sensor. Refer to Intake Air Temperature Sensor Replacement . Did you complete the replacement? | -- | Go to Step 12 | -- | ||||||||
11 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 12 | -- | ||||||||
12 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 13 | ||||||||
13 | Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||||
