The powertrain control module (PCM) monitors the high side refrigerant pressure via a 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 pressure is high the PCM commands the cooling fans on. When pressure is too high or too low the PCM will not allow the A/C compressor clutch to engage.
The engine is running.
• | The PCM detects the signal circuit is less than 5 counts (0.09 volt) or more than 250 counts (4.90 volt) when the A/C is requested. |
• | The PCM detects the signal circuit is more than 363 psi (4.0 volt) when the A/C is not requested. |
• | The condition exists for 15 seconds. |
• | The PCM will not illuminate the malfunction indicator lamp (MIL). |
• | The PCM stores the failure records. |
• | The A/C compressor clutch is disabled. |
• | The DTC will become history if the PCM no longer detects a failure. |
• | The history DTC will clear after 40 fault free ignition cycles. |
• | The DTC can be cleared with a scan tool. |
The number(s) below refer to the step number(s) on the diagnostic table.
Tests for the proper operation of the circuit in the high voltage range.
Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.
Tests for a short to ground in the 5 volt reference circuit.
Step | Action | Value(s) | Yes | No |
---|---|---|---|---|
Schematic Reference: HVAC Schematics | ||||
1 | Did you perform the HVAC Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls |
2 |
Important: This step must be performed in an area with an ambient temperature that is greater than 0°C (32°F).
Does the scan tool indicate that the A/C High Side Pressure parameter is within the specified range? | 0.2-3.76 V | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
Does the scan tool indicate that the A/C High Side Pressure parameter is greater than the specified range? | 0.2 V | Go to Step 4 | Go to Step 8 | |
Does the scan tool indicate that the A/C High Side Pressure parameter is less than the specified value? | 3.76 V | Go to Step 5 | Go to Step 9 | |
Does the scan tool indicate that the A/C High Side Pressure parameter is greater than the specified value? | 4.9 V | Go to Step 7 | Go to Step 6 | |
6 | Test the 5 volt reference circuit of the A/C refrigerant pressure sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
7 | Test the 5 volt reference circuit of the A/C refrigerant pressure sensor for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 11 |
8 | Test the signal circuit of the A/C refrigerant pressure sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
9 | Test the signal circuit of the A/C refrigerant pressure sensor for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 10 |
10 | 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 in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
11 | 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 in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 13 |
12 | Inspect for poor connections at the harness connector of the powertrain control module. 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 15 | Go to Step 14 |
13 | 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 15 | -- |
14 |
Important: Perform the programming procedure for the powertrain control module. Replace the powertrain control module. Refer to Powertrain Control Module Replacement in Engine Controls-2.2 L (L43). Did you complete the replacement? | -- | Go to Step 15 | -- |
15 |
Does the DTC reset? | -- | Go to Step 2 | System OK |