GM Service Manual Online
For 1990-2009 cars only

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 Descriptor

DTC P244C: Catalyst Temperature Too Low During Regeneration

Diagnostic Fault Information

Circuit

Short to Ground

Open

Short to Voltage

Catalytic Converter 1 Sensor Signal

P0545

P0546

P0546

Typical Scan Tool Data

Catalytic Converter 1

Circuit

Short to Ground

Open

Short to Voltage

Operating Conditions: Ignition ON

Parameter Normal Range: 0-1000°C (32-1832°F)

Catalytic Converter 1 Sensor Signal

1000°C (1832°F)

0°C (32°F)

0°C (32°F)

Circuit/System Description

The engine control module (ECM) supplies 5 volts to the exhaust gas temperature 1 sensor on the 5-volt reference circuit. The ECM also provides a ground on the low reference circuit. The exhaust gas temperature 1 sensor provides a signal to the ECM on the exhaust gas temperature 1 signal circuit which is relative to the pressure changes in the manifold. The ECM should detect a low signal voltage at a exhaust gas temperature 1, such as low engine load. The ECM should detect high signal voltage at a high exhaust gas temperature 1, such as high engine load. The ECM monitors the exhaust gas temperature 1 sensor signal for voltage outside the normal range of the exhaust gas temperature 1 sensor.

Conditions for Running the DTC

    • The battery voltage is between 10-16 volts.
    • The ignition switch is ON for longer than 2 seconds.
    • The DPF status is normal. The DPF differential pressure status is one, and the DPF warning counter status is 2.

Conditions for Setting the DTC

The ECM detects that the catalyst temperature is continuously low.

Action Taken When the DTC Sets

DTC P244C is a Type A DTC.

Conditions for Clearing the DTC

DTC P244C is a Type A DTC.

Diagnostic Aids

An incorrectly installed DOC exhaust gas temperature sensor will cause this DTC to set.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Engine Controls Component Views
    •  Engine Control Module Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

Verify the integrity of the engine exhaust system and fuel system by inspecting for the following conditions:

    • Damaged components
    • Loose or improper installation

Circuit/System Testing

Important: You must perform Circuit/System Verification before proceeding with Circuit/System Testing.

  1. Ignition OFF, disconnect the harness connector at the DOC exhaust gas temperature 1 sensor.
  2. Ignition OFF, using a DMM, measure the voltage between the signal circuit and a low reference circuit.
  3. If less than 4.8 volts, test the low reference circuit for an open/high resistance.
  4. Ignition ON, verify the scan tool exhaust gas temperature 1 parameter is more than 950°C (1742°F).
  5. If greater than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the control module.
  6. Install a 3-amp fused jumper wire between the signal circuit terminal A and the low reference circuit . Verify the scan tool exhaust gas temperature 1 parameter is less than 50°C (122°F).
  7. If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the control module.
    If all circuits test normal, test or replace the exhaust gas temperature 1 sensor.
  8. Ignition ON for longer than 30 seconds, learning the zero position of DPF differential pressure.
  9. Perform the DPF regeneration.
  10. Start the engine and operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the freeze Frame/Failure Records.
  11. If detect the DTC, replace the control module.
  12. Ignition OFF, inspect the DPF filter.
  13. If a broken, clogged, or melted DPF filter is found, replace the DPF filter.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    • DOC Exhaust Gas Temperature Sensor Replacement
    • DPF Filter Replacement setup, and programming
    •  Control Module References for ECM replacement, setup, and programming