Diagnostic Instructions

DTC Descriptors

DTC P0545: Exhaust Gas Temperature (EGT) Sensor 1 Circuit Low Voltage

DTC P0546: Exhaust Gas Temperature (EGT) Sensor 1 Circuit High Voltage

Diagnostic Fault Information

Circuit	Short to Ground	Open	Short to Voltage
EGT Sensor 1 Signal	P0545	P0546	P0546
Exhaust Gas Temperature Sensor 1 Low Reference	--	P0546	P0546

Typical Scan Tool Data

EGT Sensor 1

Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: Ignition ON Parameter Normal Range: 0-1 000°C (32-1,832°F)
Exhaust Gas Temperature Sensor 1 Signal	450°C (1,742°F)	0°C (32°F)	0°C (32°F)
Exhaust Gas Temperature Sensor 1 Low Reference	--	--	--

Circuit/System Description

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

Conditions for Running the DTC

P0545

P0546

Conditions for Setting the DTC

P0545

The ECM detects that the DOC exhaust gas temperature sensor 1 signal voltage is less than 0.18 volt.

P0546

The ECM detects that the DOC exhaust gas temperature sensor 1 signal voltage is more than 4.9 volts.

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

Inspect for any recent engine mechanical repairs. An incorrectly installed EGT sensor 1 will cause this DTC to set.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Engine Controls Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Verify the integrity of the EGT sensor by inspecting for the following conditions:

Circuit/System Testing

Important: Perform the Circuit/System Verification before proceeding with the Circuit/System Testing.

1. Ignition OFF, disconnect the harness connector at the exhaust gas temperature 1 sensor.
2. Ignition ON, verify the scan tool Exhaust Gas Temperature 1 parameter is less than 1°C (34°F).

⇒	If greater than the specified range, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the ECM.

3. Install a 3-amp fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool Exhaust Gas Temperature 1 parameter is more than 950°C (1,742°F).

⇒	If less than the specified range, test the signal circuit and low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

4. If all circuits test normal, replace the exhaust gas temperature 1 sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.