The engine control module (ECM) monitors the high side refrigerant pressure through an air conditioning (A/C) refrigerant pressure sensor. When the pressure is high the signal voltage is high. When the pressure is low, the signal voltage is low. When the pressure is high, the ECM commands the cooling fans ON. When the pressure is too high or too low, the ECM will not allow the A/C compressor clutch to engage.
This diagnostic procedure supports the following DTCs:
• | DTC P0532 A/C Refrigerant Pressure Sensor Circuit Low Voltage |
• | DTC P0533 A/C Refrigerant Pressure Sensor Circuit High Voltage |
• | The engine is running. |
• | A/C OFF when P0532 is set. |
The ECM detects an A/C pressure of less than 0.1 volt for 1.6 seconds.
The ECM detects an A/C pressure of more than 4.9 volts for 1.6 seconds.
• | The ECM will not illuminate the malfunction indicator lamp (MIL). |
• | The ECM stores the failure records. |
• | The A/C compressor clutch is disabled. |
• | SERVICE A/C SYSTEM displays on the driver information center (DIC). |
• | A/C OFF displays on the HVAC control module. |
• | The DTC will become history if the ECM no longer detects a failure. |
• | The history DTC will clear after 40 fault-free ignition cycles. |
• | Clear the DTC with a scan tool then cycle the ignition. |
If the condition is not present, refer to Testing for Intermittent Conditions and Poor Connections .
The numbers below refer to the step numbers on the diagnostic table.
Tests for the proper operation of the circuit in the low voltage range.
Tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.
Tests for a short to voltage in the 5-volt reference circuit.
Step | Action | Values | Yes | No | ||||||
---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views | ||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||
2 |
Does the scan tool indicate that the A/C High Side Pressure parameter is within the specified range? | 0.2-4.88 V | Go to Diagnostic Aids | Go to Step 3 | ||||||
Does the scan tool indicate that the A/C High Side Pressure parameter is less than the specified value? | 0.2 V | Go to Step 4 | Go to Step 10 | |||||||
Does the scan tool indicate that the A/C High Side Pressure parameter is greater than the specified value? | 4.88 V | Go to Step 5 | Go to Step 8 | |||||||
Does the voltage measure less than the specified value? | 5.5 V | Go to Step 6 | Go to Step 7 | |||||||
6 | Does the voltage measure near the specified value? | 5 V | Go to Step 12 | Go to Step 11 | ||||||
7 | Test the 5-volt reference circuit of the A/C refrigerant pressure sensor for short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 | ||||||
8 | Test the 5-volt reference circuit of the A/C refrigerant pressure sensor for the following:
Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 9 | ||||||
9 | Test the signal circuit of the A/C refrigerant pressure sensor for the following:
Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 | ||||||
10 | Test the signal circuit of the A/C refrigerant pressure sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 | ||||||
11 | Test the low reference circuit of the A/C refrigerant pressure sensor for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 | ||||||
12 | Inspect for poor connections at the harness connector of the A/C refrigerant pressure sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 14 | ||||||
13 | Inspect for poor connections at the harness connector of the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15 | ||||||
14 | Replace the A/C refrigerant pressure sensor. Refer to Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement . Did you complete the replacement? | -- | Go to Step 16 | -- | ||||||
15 | Replace the ECM. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement? | -- | Go to Step 16 | -- | ||||||
16 |
Does the DTC reset? | -- | Go to Step 2 | System OK |