Hummer H3. Manual — part 1289

SCAN TOOL DATA LIST

Body Control Module (BCM)

Powertrain Control Module (PCM)

SCAN TOOL DATA DEFINITIONS

AC Pressure Sensor

The scan tool displays 0-3450 kPa (0-500 psi). The voltage applied to the powertrain
control module (PCM) input from the A/C refrigerant pressure sensor is converted to a
pressure value.

A/C Relay Command

The scan tool displays On/Off. The scan tool displays the control decision for the
compressor clutch relay output as determined by the PCM.

in a speed position other than OFF for output to
function. When OFF is selected with the scan tool,
the BCM removes the ground for the IGN 3 relay
and the blower motor is disabled.

Scan Tool Parameter

Data List

Units Displayed

Typical Data

Value

Operating Conditions: Engine idling, A/C ON, ambient air temperature between 22-

27°C (70-80°F)

A/C Request

Inputs

Yes, No

Yes

Scan Tool Parameter

Data List

Units Displayed

Typical Data

Value

Operating Conditions: Engine idling, A/C ON, ambient air temperature between 22-

27°C (70-80°F)

A/C Pressure Sensor

Engine Data 2

kPa, psi

Varies

A/C Relay Command

Engine Data 1,

Engine Data 2

On, Off

On

A/C Request Signal

Engine Data 2

Yes, No

Yes

ECT Sensor

Engine Data 1,

Engine Data 2

°C/°F

Varies

2007 Hummer H3

2007 HVAC HVAC - Manual - H3

A/C Request

The scan tool displays Yes/No. Yes is displayed when the body control module (BCM)
receives an input from the HVAC control assembly for an A/C request. No is displayed
when there is no A/C request.

A/C Request Signal

The scan tool displays Yes/No. The scan tool displays Yes when the PCM receives a class 2
message from the body control module (BCM) to engage the A/C compressor clutch. The
BCM receives a voltage input from the HVAC control assembly through the evaporator
temperature sensor for an A/C request. The scan tool displays No when the PCM receives a
class 2 message from the BCM to disengage the A/C compressor clutch.

ECT Sensor

The scan tool displays -39 to 140°C (-38 to 284°F). The voltage applied to the PCM input
from the engine coolant temperature sensor is converted to a temperature value.

DTC P0532 OR P0533

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Review Strategy Based Diagnosis for an overview of the diagnostic approach.

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P0532

Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit

DTC P0533

Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit Low Voltage

Diagnostic Fault Information

DTC P0532 or P0533

Circuit

Short to

Ground

Open/High

Resistance

Short to

Voltage

Signal

Performance

2007 Hummer H3

2007 HVAC HVAC - Manual - H3

Circuit/System Description

The engine control module (ECM) monitors the high side refrigerant pressure through the A/C
refrigerant pressure sensor. The ECM supplies a 5-volt reference and a low reference to the
sensor. Changes in the A/C refrigerant pressure cause the 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 11-18 volts.

Conditions for Setting the DTC

The ECM detects that the A/C pressure is less than 1 psi (0.01 volt).

The ECM detects that the A/C pressure is more than 428 psi (4.92 volts).

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 will become history if the ECM no longer detects a failure.

Diagnostic Aids

A malfunction within the refrigerant system causing high pressure can cause this DTC to set.

5-Volt Reference Circuit

P0532

P0532

-

-

A/C Refrigerant Pressure Sensor
Signal Circuit

P0532

P0532

P0533

-

Low Reference Circuit

-

P0533

-

-

2007 Hummer H3

2007 HVAC HVAC - Manual - H3

Reference Information

Schematic Reference

HVAC Schematics

Description and Operation

Air Temperature Description and Operation

Air Delivery Description and Operation

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs

Scan Tool Reference

Scan Tool Output Controls

Scan Tool Data List

Scan Tool Data Definitions

Circuit/System Verification

Ignition ON, observe the scan tool A/C High Side Pressure Sensor parameter. The reading should
be between 1 psi and 428 psi.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the A/C pressure sensor.

2. Ignition OFF, test for less than 1 ohm of resistance between the low reference circuit

terminal 1 and ground.

If greater than 1 ohm, test the low reference circuit for an open/high resistance. If the
circuit tests normal, replace the ECM.

3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 2 and

ground.

If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an

2007 Hummer H3

2007 HVAC HVAC - Manual - H3