GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1998 🢒 Seville 🢒 DTC 🢒 DTC B1331 Right A/C Discharge Sensor Fault

Object Number: 142267 Size: MF
HVAC Air Delivery/Temperature Control Schematics Temperature Sensors
HVAC Schematic Icons
HVAC Air Delivery/Temperature Control Schematics Temperature Sensors

Circuit Description

The right A/C temperature sensor is a thermistor that controls signal voltage to the Instrument Panel Integration Module (IPM). The IPM applies voltage on circuit 517. When the sensor is cold, the resistance is high and the IPM will sense a high signal voltage at terminal B7, connector C2. When the sensor warms, resistance is reduced and the signal voltage is pulled low through circuit 61. Signal voltage will vary from 5 V (open circuit) to 0 V (short circuit).

Conditions for Setting the DTC
    • The ignition is ON.
    • Circuit open or short.

Action Taken When the DTC Sets
    • A default value of 128 counts and 24°C (75°F) will be used by the IPM.
    • The default valve allows the system to operate.
    • If air delivery is on A/C or bilevel, the air mix two door will cycle between full cold and full hot.

Conditions for Clearing the MIL/DTC
    • Using a scan tool.
    • A current DTC will clear when the diagnostic runs and does not fail.
    • IPM battery voltage is interrupted.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step determines whether the Body Control Module (BCM) Diagnostic System Check was performed.

    2.

  2. This step ensures that the DTC was not set in error.

    3.

  3. This step determines whether the cause of the malfunction is the sensor, or an open or a short in a circuit.

    4.

  4. The scan tool verifies proper sensor operation. Clear all the DTCs after the repair procedure is complete.

Step

Action

Value(s)

Yes

No

1

Was the IPM/DIM/RIM diagnostic system check performed?

--

Go to Step 2

Go to Diagnostic System Check - Body Control System

2
  1. Turn the ignition ON.
  2. Disconnect the sensor.
  3. Measure the voltage between sensor harness connector terminal A and B.

Is the voltage within the specified range?

4.5-5.5 V

Go to Step 3

Go to Step 4

3

  1. Turn the ignition OFF.
  2. Reconnect the sensor.
  3. Connect the scan tool.
  4. Turn the ignition ON.
  5. Clear the DTC using the scan tool.
  6. Start the engine.

Did DTC reset?

--

Go to Step 4

Go to Intermittents and Poor Connections in HVAC Systems with A/C-Automatic

4

  1. Select IPM open/short data on the scan tool.
  2. Display RH A/C temperature data.
  3. Start the engine.
  4. Unplug the RH A/C temperature sensor.
  5. The RH A/C temperature voltage increases to 118 degrees celcius.
  6. Reconnect the RH A/C temperature sensor connector.

Did the RH A/C temperature sensor remain at the specified value?

118 degrees celcius

Go to Step 6

Go to Step 4

5
  1. Check CKT 61 (YEL) for an open, if no open is found.
  2. Replace the Left A/C Discharge Sensor
  3. Refer to Inside Air Temperature Sensor Replacement in HVAC with Automatic A/C Systems.

--

Go to Step 9

--

6

Inspect CKT 61 (YEL) for a short .

Was a short located?

--

Go to Step 7

Go to Step 8

7
  1. Inspect CKT 517 (BLK) for an open or short .
  2. If OK, replace the IPM. Refer to Body Control Module Replacement in HVAC Systems with A/C-Automatic.

Is the replacement complete?

--

Go to Step 9

--

8

Repair short in CKT 61 (YEL).

Is the repair complete?

--

Go to Step 9

--

9

  1. Using the scan tool, clear all the DTCs.
  2. Confirm proper operation of the A/C system.

Is the A/C system operating normally?

--

Go to Diagnostic System Check - Body Control System

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