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DTC P0545 or P0546

DTC P0545 or P0546

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 P0545 12

Exhaust Gas Temperature Sensor 1 Circuit Low Voltage

DTC P0546 11

Exhaust Gas Temperature Sensor 1 Circuit High Voltage

Circuit/System Description

The exhaust gas temperature sensors are variable resistors that measures the temperature of the exhaust gas. The exhaust gas temperature sensor 1 is located in the exhaust pipe after the catalytic converter. The exhaust gas temperature 2 sensor is located in the exhaust gas particulate filter. The engine control module (ECM) supplies 5 V to the exhaust gas temperature signal circuit and supplies a ground to the low reference circuit. The exhaust gas temperature sensor temperature information is used by the ECM during the exhaust gas particulate filter cleaning process.

The following table illustrates the difference between temperature, resistance, and voltage:

Exhaust Gas Temperature Exhaust Gas Temperature Resistance Exhaust Gas Temperature Signal Voltage
Cold

High

High

Warm

Low

Low



Conditions for Running the DTC


• The ignition is ON.

• The DTCs run continuously when the above condition is met.


Conditions for Setting the DTC

P0545

The ECM detects that the exhaust gas temperature sensor is less than 0.1 V for greater than 1 s.

P0546

The ECM detects that the exhaust gas temperature sensor is greater than 4.9 V for greater than 1 s.

Action Taken When the DTC Sets

DTCs P0545, and P0546 are Type A DTCs.

Conditions for Clearing the DTC

DTCs P0545, and P0546 are Type A DTCs.

Diagnostic Aids


• After starting the engine, the exhaust gas temperature sensor temperature should rise steadily, then stabilize after the engine reaches operating temperature.

• If the vehicle has set overnight, the exhaust gas temperature sensor and the intake air temperature (IAT) sensor values should display within 3°C (5°F).


Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component 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

Control Module References for scan tool information

Circuit/System Verification


1. With the engine running, check the DTC Info with a scan tool. DTC P0545 or P0546 are not set.

2. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.


Circuit/System Testing


1. Ignition OFF, disconnect the harness connector at the B131A Exhaust Temperature Sensor 1.

2. Test for less than 5 Ω between the low reference circuit terminal 2 and ground.

3. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

4. Disconnect the harness connector at both cooling fans.

5. Ignition ON, verify the scan tool Exhaust Gas Temperature Sensor 1 parameter is at 5 V.

6. If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.

7.
Note

If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.


Install a 1 A fused jumper wire between the signal circuit terminal 1 and ground. Verify the scan tool Exhaust Gas Temperature Sensor 1 parameter is at 0 V.

8. If greater 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 K20 Engine Control Module.

9. If all circuits test normal, test or replace the B131A Exhaust Temperature Sensor 1.


Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.


• Exhaust Temperature Sensor Replacement - Position 1 (LBY/A20DTR) Exhaust Temperature Sensor Replacement - Position 1 (LBS/A20DTH)

• Control Module References for ECM replacement, setup, and programming