DTC Troubleshooting: P0533 (191)
DTC P0533:
 A/C Pressure Sensor Circuit High Voltage
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
  1. Start the engine, and let it idle.
  1. Turn the blower switch on.
  1. Turn the A/C switch on.
  1. Check the A/C PRESSURE SENSOR in the DATA LIST with the HDS.
Is there about 4.75 V or more?
YES -
Go to Step 5 .
NO -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the A/C pressure sensor and the ECM.■
  1. Turn the ignition switch OFF.
  1. Disconnect the A/C pressure sensor 3P connector.
  1. Connect A/C pressure sensor 3P connector terminals No. 2 and No. 3 with a jumper wire.
  1. Turn the ignition switch ON (II).
  1. Check the A/C PRESSURE SENSOR in the DATA LIST with the HDS.
Is there about 4.75 V or more?
YES -
Go to Step 10 .
NO -
Go to Step 22 .
  1. Turn the ignition switch OFF.
  1. Remove the jumper wire from the A/C pressure sensor 3P connector.
  1. Turn the ignition switch ON (II).
  1. Measure voltage between A/C pressure sensor 3P connector terminals No. 1 and No. 3.
Is there about 5 V?
YES -
Go to Step 14 .
NO -
Go to Step 18 .
  1. Turn the ignition switch OFF.
  1. Jump the SCS line with the HDS.
  1. Disconnect ECM connector A (44P).
  1. Check for continuity between A/C pressure sensor 3P connector terminal No. 2 and ECM connector terminal A16.
Is there continuity?
YES -
Go to Step 32 .
NO -
Repair open in the wire between the ECM (A16) and the A/C pressure sensor, then go to Step 24 .
  1. Turn the ignition switch OFF.
  1. Jump the SCS line with the HDS.
  1. Disconnect ECM connector A (44P).
  1. Check for continuity between A/C pressure sensor 3P connector terminal No. 3 and ECM connector terminal A9.
Is there continuity?
YES -
Go to Step 32 .
NO -
Repair open in the wire between the ECM (A9) and the A/C pressure sensor, then go to Step 24 .
  1. Turn the ignition switch OFF.
  1. Reconnect all connectors and the battery.
  1. Turn the ignition switch ON (II).
  1. Reset the ECM with the HDS.
  1. Start the engine, and let it idle.
  1. Turn the blower switch on.
  1. Turn the A/C switch on.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0533 indicated?
YES -
Check for poor connections or loose terminals at the A/C pressure sensor and the ECM, then go to Step 1 .
NO -
Troubleshooting is complete. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.■
  1. Reconnect all connectors.
  1. Start the engine, and let it idle.
  1. Turn the blower switch on.
  1. Turn the A/C switch on.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0533 indicated?
YES -
Check for poor connections or loose terminals at the A/C pressure sensor and the ECM. If the ECM was updated, substitute a known-good ECM, then go to Step 34 . If the ECM was substituted, go to Step 1 .
NO -
If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.■