P0545
P0545-EXHAUST GAS TEMPERATURE SENSOR CIRCUIT LOW - BANK 1 SENSOR 1
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The after treatment temperature sensors are used by the Powertrain Control Module (PCM) to monitor the engine exhaust temperatures in the after treatment system. The after treatment temperature sensors are thermistors and change resistance based on the temperature being measured. The PCM provides a 5-Volt reference voltage to the sensor. The PCM monitors the change in signal voltage and converts this to a temperature value. When the exhaust gas temperature is cold, the sensor or thermistor resistance is high. The PCM signal voltage only pulls down a small amount through the sensor to ground. Therefore, the PCM senses a high signal voltage or low temperature. When the exhaust gas temperature is hot, the sensor resistance is low. The signal voltage pulls down a large amount. Therefore, the PCM senses a low signal voltage, or a high temperature. The PCM will set the fault code if it detects that the after treatment Diesel Particulate Filter inlet Exhaust Gas Temperature Sensor Signal voltage is less than a calibrated voltage for longer than a calibrated period. The PCM illuminates the MIL lamp immediately when the diagnostic runs and fails. A default value for the after treatment diesel particulate filter inlet temperature reading will be used and active regeneration of the diesel particulate filter will be disabled. The PCM will turn off the MIL lamp immediately after the diagnostic runs and passes.
- When Monitored:
Ignition on.
- Set Condition:
The Exhaust Gas Temperature Sensor 1/1 Signal voltage is below 0.25 of a Volt for 15.0 seconds.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
1. ACTIVE DTC
1. Turn the ignition on.
2. With the scan tool, record all Freeze frame data.
3. With the scan tool, erase DTCs.
4. Turn the ignition off for 75 seconds.
5. Turn the ignition on.
6. With the scan tool, read DTCs.
Did the DTC reset?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test
2. CHECK THE (K185) EXHAUST TEMPERATURE SENSOR 1/1 SIGNAL CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the Exhaust Gas Temperature Sensor 1/1.
3. Disconnect the PCM C2 harness connector.
4. Measure the resistance between ground and the (K185) Exhaust Temperature Sensor 1/1 Signal circuit at the Exhaust Gas Temperature Sensor 1/1 harness connector.
Is the resistance below 10k Ohms?
Yes
- Repair the (K185) Exhaust Gas Temperature Sensor 1/1 Signal circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.
No
- Go To 3
3. CHECK FOR THE (K185) EXHAUST TEMPERATURE SENSOR 1/1 SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
1. Turn the ignition off.
NOTE: Check connectors - Clean/repair as necessary.
2. Measure the resistance between the (K185) Exhaust Temperature Sensor 1/1 Signal circuit and (K900) Sensor Ground circuit at the PCM C2 harness connector.
Is the resistance below 10k Ohms?
Yes
- Repair the short between the (K185) Exhaust Temperature Sensor 1/1 Signal circuit and (K900) Sensor Ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.
No
- Go To 4
4. CHECK THE EXHAUST GAS TEMPERATURE SENSOR
1. Reconnect the Exhaust Gas Temperature Sensor 1/1 harness connector.
2. Reconnect the PCM C2 harness connector.
3. Turn the ignition on.
4. With the scan tool, erase DTCs.
5. Turn the ignition off for 75 seconds.
6. Disconnect the Exhaust Gas Temperature Sensor 1/1 harness connector.
7. Turn the ignition on.
8. With the scan tool, read DTCs.
Does DTC P0546 become active?
Yes
- Replace the Exhaust Temperature Sensor 1/1.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.
No
- Replace the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.