GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2009 🢒 Vibe - FWD 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC B1423

Circuit Description

The pressure sensor is installed on the high pressure line to detect refrigerant pressure, outputs a refrigerant pressure signal to the A/C amplifier. The A/C amplifier converts this signal to pressure according to the sensor characteristics to control the compressor. When refrigerant pressure on the high pressure side is extremely low 0.19 Mpa (2.0 kgf/cm², (28 psi)) or extremely high 3.14 Mpa (32.0 kgf/cm², (455 psi)) or more, this DTC will set.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1423 Pressure Sensor Circuit

Conditions for Running the DTC

This DTC shall run when the engine is running.

Conditions for Setting the DTC
    • When refrigerant pressure on the high pressure side is extremely low 0.19 MPa (2.0 kgf/cm², (28 psi)) or less, or extremely high 03.14 MPa (32.0 kgf/cm², (455 psi)) or more.
    • Open or short in pressure sensor circuit.

Action Taken When the DTC Sets

The

Conditions for Clearing the DTC

The DTC will clear when conditions for setting the DTC have been repaired.

Step

Action

Value(s)

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: Component Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Turn OFF ignition.
  2. Disconnect the A/C pressure sensor harness connector.
  3. Turn On the ignition, with engine Off.
  4. Measure the voltage between the A/C pressure sensor connector A16 terminal 3 and body ground.

Is the voltage measured within the specified values?

4.75 -5.25 V

Go to Step 3

Go to Step 6

3

  1. Turn OFF ignition.
  2. Measure the resistance between the A/C pressure sensor connector A16 terminal 1 and body ground.

Is the resistance measured within the specified value?

Below 1 Ohm

Go to Step 4

Go to Step 7

4
  1. Reconnect the A/C pressure sensor connector.
  2. Remove the A/C amplifier with connectors still connected.
  3. Turn On the ignition, with engine Off.
  4. Measure the voltage between the A/C amplifier connector E62 terminal 6 and body ground.

Is the voltage measured within the specified values?

0.7-4.8 V

Go to Step 5

Go to Step 8

5
  1. Set up for voltage measurement as follows:
    2. • Vehicle doors - Fully open
    • Temperature setting - MAX COLD
    • Blower speed - HI
    • A/C switch - ON
    • R/F switch - RECIRCULATION
    • Interior temperature - 25 to 35°C (77 to 95°F)
    • Engine speed - 2,000 rpm
  2. With A/C On, measure the resistance between the A/C amplifier connector E62 terminal 6 and body ground.

Is the voltage measured within the specified values?

0.7-4.8 V

Go to Step 22

Go to Step 14

6
  1. Disconnect the A/C amplifier connector.
  2. Turn On the ignition, with engine Off.
  3. Measure the voltage between the A/C pressure sensor connector A16 terminal 3 and the A/C amplifier connector E62 terminal 1.
  4. Measure the voltage between the A/C amplifier connector E62 terminal 1 and body ground .

Are the voltages measured within the specified values?

Between connector A16 terminal 3 and E62 terminal 1 = Below 1 Ohm

Between connector E62 terminal 1 and body ground = 10 Kohm or higher

Go to Step 22

Go to Step 19

7
  1. Disconnect the A/C amplifier connector.
  2. Turn On the ignition, with engine Off.
  3. Measure the voltage between the A/C pressure sensor connector A16 terminal 1 and the A/C amplifier connector E62 terminal 4.
  4. Measure the voltage between the A/C amplifier connector E62 terminal 4 and body ground .

Are the voltages measured within the specified values?

Between connector A16 terminal 1 and E62 terminal 4 = Below 1 Ohm

Between connector E62 terminal 4 and body ground = 10 Kohm or higher

Go to Step 22

Go to Step 19

8
  1. Disconnect the A/C amplifier connector.
  2. Turn On the ignition, with engine Off.
  3. Measure the voltage between the A/C pressure sensor connector A16 terminal 2 and the A/C amplifier connector E62 terminal 6.
  4. Measure the voltage between the A/C amplifier connector E62 terminal 6 and body ground .

Are the voltages measured within the specified values?

Between connector A16 terminal 2 and E62 terminal 6 = Below 1 Ohm

Between connector E62 terminal 6 and body ground = 10 Kohm or higher

Go to Step 9

Go to Step 19

9
  1. Install the manifold gauge set.
  2. Recover the refrigerant from the A/C system using a refrigerant recovery unit.
  3. Evacuate the A/C system and check that vacuum can be maintained.

Was vacuum maintained?

--

Go to Step 10

Go to Step 13

10
  1. Using a refrigerant recovery unit, recover the refrigerant.
  2. Evacuate the A/C system.
  3. Add the appropriate amount of refrigerant.

Did you complete the refrigerant charging?

--

Go to Step 11

--

11
  1. Set up for DTC recheck as follows:
    2. • Vehicle doors - Fully open
    • Temperature setting - MAX COLD
    • Blower speed - HI
    • A/C switch - ON
    • R/F switch - RECIRCULATION
    • Interior temperature - 25 to 35°C (77 to 95°F)
    • Engine speed - 2,000 rpm
  2. With the scan tool, check to see if DTC resets.

Does DTC reset?

--

Go to Step 12

Go to Step 25

12
  1. Install the manifold gauge set.
  2. Disconnect the A/C pressure sensor connector.
  3. Connect the three 1.5-volt dry cell batteries positive lead to terminal 3 and the negative lead to terminal 1.
  4. Connect a DMM positive lead to terminal 2 and the negative lead to terminal 1.
  5. Measure the voltage with refrigerant pressure between 0.39 - 3.187 MPa (57 - 463 psi).

Is the voltage measured within the specified values?

1.0-4.8 V

Go to Step 22

Go to Step 20

13
  1. Identify the area where the refrigerant leaks from.
  2. Repair the identified area of the A/C system
  3. Evacuate the A/C system.

Did you complete the repair?

--

Go to Step 15

--

14

Check that the cooling fan operates normally.

Does the cooling fan operate normally?

--

Go to Step 17

Go to Cooling Fan Inoperative

15
  1. Using a refrigerant recovery unit, recover the refrigerant.
  2. Evacuate the A/C system.
  3. Add the appropriate amount of refrigerant.

Did you complete the refrigerant charging?

--

Go to Step 16

--

16
  1. Set up for DTC recheck as follows:
    2. • Vehicle doors - Fully open
    • Temperature setting - MAX COLD
    • Blower speed - HI
    • A/C switch - ON
    • R/F switch - RECIRCULATION
    • Interior temperature - 25 to 35°C (77 to 95°F)
    • Engine speed - 2,000 rpm
  2. With the scan tool, check to see if DTC resets.

Does DTC reset?

--

Go to Step 21

Go to Step 23

17
  1. Using a refrigerant recovery unit, recover the refrigerant.
  2. Evacuate the A/C system.
  3. Add the appropriate amount of refrigerant.

Did you complete the refrigerant charging?

--

Go to Step 18

--

18
  1. Set up for DTC recheck as follows:
    2. • Vehicle doors - Fully open
    • Temperature setting - MAX COLD
    • Blower speed - HI
    • A/C switch - ON
    • R/F switch - RECIRCULATION
    • Interior temperature - 25 to 35°C (77 to 95°F)
    • Engine speed - 2,000 rpm
  2. With the scan tool, check to see if DTC resets.

Does DTC reset?

--

Go to Step 24

Go to Step 25

19

Repair or replace harness or connector between the ambient temperature sensor and instrument panel.

Did you complete the repair or replacement?

--

Go to Step 25

--

20

Replace the A/C pressure sensor.

Did you complete the replacement?

--

Go to Step 25

--

21

Replace the expansion valve.

Did you complete the replacement?

--

Go to Step 25

--

22

Replace the A/C amplifier.

Did you complete the replacement?

--

Go to Step 25

--

23

Replace the cooler dryer.

Did you complete the replacement?

--

Go to Step 25

--

24

Replace the condenser.

Did you complete the replacement?

--

Go to Step 25

--

25
  1. Use the scan tool in order to clear the DTC.
  2. Operate the vehicle within the Conditions for Running the DTC, as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK