With Manual AC

DTC P0533 (ECM)

CIRCUIT DESCRIPTION




The engine control module (ECM) monitors the high side refrigerant pressure through the A/C refrigerant pressure sensor. The ECM supplies a 5.0 voltreference and a low reference to the sensor. Changes in the A/C refrigerant pressure cause the A/C refrigerant pressure sensor signal to the ECM to vary. 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 ECM commands the cooling fans on. When pressure is too high or too low, the ECM will not allow the A/C compressor clutch to engage.

CONDITIONS FOR RUNNING THE DTC
- Engine is running.
- Any of the conditions for setting the DTC are met for 15 seconds.
- Battery voltage is between 11 to 18 volts.

CONDITIONS FOR SETTING THE DTC
- The ECM detects that the A/C pressure is less than 0 psi (0.01 volts).
- The ECM detects that the A/C pressure is more than 428 psi (4.92 volts).

P0530
The ECM detects a too low or too high signal on the A/C refrigerant pressure sensor signal circuit.

P0532
The ECM detects a low signal on the A/C refrigerant pressure sensor signal circuit.

P0533
The ECM detects a high signal on the A/C refrigerant pressure sensor signal circuit.

ACTION TAKEN WHEN THE DTC SETS
- The ECM will not illuminate the malfunction indicator lamp (MIL)
- The ECM stores the Failure Records.
- The A/C compressor clutch is disabled.

CONDITIONS FOR CLEARING THE DTC
- The history DTC will clear after 40 consecutive ignition cycles have occurred without a malfunction.
- The DTC can be cleared by using the scan tool.
- The DTC will become history if the ECM no longer detects a failure.

DIAGNOSTIC AIDS
Test the following conditions:
- Visually inspect the sensor for contamination or damage.
- Inspect for the following that may affect the sensors accuracy:
- A malfunction within the refrigerant system causing high pressure.
- Visually inspect the A/C components and lines for damage.

TEST DESCRIPTION

Steps 1-8:

Steps 9-17:

The numbers below refer to the step numbers on the diagnostic table.
4. Tests for the proper operation of the circuit in the low voltage range.
5. 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.
6. Tests for a short to voltage in the 5 volt reference circuit.
7. Tests for a high resistance or an open in the low reference circuit.