Exhaust Gas Temperature Sensor Circuit Low (Bank 1 Sensor 1)
P0545 indicates the exhaust gas temperature (EGT) sensor circuit for Bank 1 Sensor 1 is reading a voltage signal that is too low. This code sets when the PCM detects a signal below the expected range, preventing accurate monitoring of exhaust temperature for emissions control and engine performance.
What You Might Notice
- Check Engine Light illuminated
- Possible rough idle or engine hesitation
- Reduced fuel economy
- Failed emissions testing
- No immediate drivability issues in most cases
Most Common Causes
- 1
Loose or corroded connector
The EGT sensor connector or wiring terminals may be loose, corroded, or making poor electrical contact, causing low voltage signal transmission to the PCM.
- 2
Broken or damaged wiring
Wires in the EGT sensor circuit may be broken, frayed, or missing insulation, causing a direct short to ground that results in low voltage reading.
- 3
Failed EGT sensor
The exhaust gas temperature sensor itself may have failed internally, producing an incorrect low voltage signal or no signal at all.
- 4
Faulty PCM or module
Although rare, the powertrain control module may have developed an internal fault preventing proper sensor signal interpretation.
How to Diagnose It
- 1
Check Loose or corroded connector — The EGT sensor connector or wiring terminals may be loose, corroded, or making poor electrical contact, causing low voltage signal transmission to the PCM.
- 2
Check Broken or damaged wiring — Wires in the EGT sensor circuit may be broken, frayed, or missing insulation, causing a direct short to ground that results in low voltage reading.
- 3
Check Failed EGT sensor — The exhaust gas temperature sensor itself may have failed internally, producing an incorrect low voltage signal or no signal at all.
- 4
Check Faulty PCM or module — Although rare, the powertrain control module may have developed an internal fault preventing proper sensor signal interpretation.
How to Fix It
- 1
Inspect and clean connector
Locate the EGT sensor connector on Bank 1 Sensor 1, disconnect it, and inspect for corrosion, loose pins, or debris. Clean with electrical contact cleaner and reconnect firmly, then clear the code and test.
- 2
Check wiring harness
Visually inspect the entire EGT sensor wiring harness from the sensor to the PCM for breaks, cuts, exposed copper, or pinched areas. Repair or replace damaged sections as needed.
- 3
Replace EGT sensor
If connector and wiring are sound, the EGT sensor has likely failed. Remove the old sensor from the exhaust manifold and install a new one, ensuring proper sealing and electrical connection.
- 4
Verify PCM function
If all wiring, connectors, and sensor are confirmed good, have the PCM tested or replaced by a qualified technician, as internal module failure is rare but possible.
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