What Does P0545 Mean?
The ECM has detected that the exhaust gas temperature sensor circuit on Bank 1, Sensor 1 is reading below the expected voltage or resistance threshold. This low-input condition typically indicates a short to ground in the sensor circuit, a failed sensor with abnormally low resistance, or a broken/grounded signal wire. The ECM cannot accurately monitor pre-catalyst exhaust temperatures.
Common Causes
35%
EGT sensor signal wire shorted to ground due to chafed insulation contacting exhaust components or chassis ground
30%
Failed EGT sensor with internal short circuit causing abnormally low resistance output
25%
Corroded connector pins at the EGT sensor creating a low-resistance path to ground through moisture intrusion
10%
ECM internal pull-down circuit fault on the EGT sensor input channel
Diagnostic Steps
1
Step 1: Disconnect the Bank 1 Sensor 1 EGT sensor connector. With key on engine off, check if the code clears or the voltage reading changes to an expected open-circuit value (typically near 5V). If voltage goes high, the sensor is the fault.
2
Step 2: Measure the EGT sensor resistance at the sensor connector. At room temperature (25C), a typical sensor reads 100-200 ohms. A reading near 0 ohms indicates an internal short.
3
Step 3: With the sensor disconnected, measure resistance from each signal wire to chassis ground at the ECM connector. Any reading below 10k ohms indicates a short to ground in the harness. Flex and wiggle the harness while monitoring for intermittent shorts.
4
Step 4: Inspect the wiring harness routing near hot exhaust components for melted insulation, chafing against metal brackets, or pinched wires. Pay close attention to areas near the exhaust manifold and turbo downpipe.
5
Step 5: Repair any damaged wiring with high-temperature rated wire and connectors. Replace the EGT sensor if internal resistance is out of specification. Clear codes and verify the sensor reads within expected range during a warm-up cycle.
Estimated Repair Cost
$70 - $300
Parts + labor, varies by vehicle and location
The ECM has detected that the exhaust gas temperature sensor circuit on Bank 1, Sensor 1 is reading below the expected voltage or resistance threshold. This low-input condition typically indicates a short to ground in the sensor circuit, a failed sensor with abnormally low resistance, or a broken/gr...
The most common cause of P0545 (Exhaust Gas Temperature Sensor Circuit Low (Bank 1 Sensor 1)) is: EGT sensor signal wire shorted to ground due to chafed insulation contacting exhaust components or chassis ground
Typical repair costs for P0545 range from $70 to $300, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A false low EGT reading could cause the ECM to miscalculate fuel enrichment strategies, potentially allowing actual exhaust temperatures to exceed safe limits and damage the turbocharger or catalytic converter.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0545 to identify the root cause.
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Quick Info
Category
Powertrain
System
Exhaust / Emission Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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