What this code means
P0545 may indicate the PCM is seeing a low exhaust gas temperature sensor signal for bank 1, sensor 1.
What the vehicle may do
- The check engine light may be on.
- Aftertreatment or regeneration behavior can be affected.
- The vehicle may use a protective strategy depending on the fault and operating conditions.
Possible fault areas
- Possible EGT sensor signal circuit concern.
- Possible connector, terminal, or harness damage from heat or routing.
- Possible exhaust leak or contamination affecting aftertreatment temperature readings.
- Possible PCM connector or module-side concern after circuit checks pass.
Diagnostic path
Code overview
On this Ford F-250 with the 6.7 Power Stroke, P0545 is an exhaust gas temperature sensor circuit low-voltage code for bank 1, sensor 1. In plain language, the PCM is seeing that EGT signal pulled lower than expected. The truck may turn on the check engine light, and aftertreatment or regeneration behavior may be affected. The broad areas to keep in mind are the EGT sensor circuit, heat-damaged or misrouted wiring, connector problems, exhaust leaks or contamination around the aftertreatment system, and PCM connector condition. For this code, the setting point is voltage less than 0.10 volt for greater than 15 seconds. If other codes are present, check what they mean first, but keep this diagnosis focused on the suspect EGT sensor indicated by P0545. Also remember that regeneration can bias EGT readings. If regeneration happens during testing, let it finish before continuing.
Start with confirmation and visual checks
Start with the basic system checks. With the ignition on, confirm the code is actually present. If the concern will not duplicate, do not guess at parts. Look for loose connections, damaged or corroded terminals, and wiggle the harness while trying to recreate the fault. If the code is present, move into the visual inspection. Check the EGT sensors for excessive heat damage, damaged wiring or connectors, incorrect harness routing, incorrect connections, and incorrect ground circuit connections to the frame. If you find a concern, repair it as needed, clear the PCM DTCs, and repeat the self-test. If that inspection is clean, turn the ignition off and inspect the exhaust system. Look for leaks at flanges and gaskets, punctures or cracks in the catalyst or diesel particulate filter, and signs of engine coolant or oil contamination. Also inspect the downstream injector area for damage, cracked or pinched lines, and fuel leaks. Any concern found here gets repaired before going deeper into circuit testing.
Check for an open in the EGT circuits
Next, check the EGT signal and SIGRTN circuits for an open. Diagnose only the suspect EGT sensor indicated by the code. On the F-Series Super Duty, some EGT sensors share connectors, so keep the connector identification straight before putting the meter on the circuit. With the ignition off, disconnect the affected EGT sensor connector and the PCM-E connector, then check the specified signal and return paths end to end. The pass point here is resistance less than 5 ohms. If the circuit is not less than 5 ohms, repair the open circuit, clear the PCM DTCs, and repeat the self-test. If it passes, keep moving.
Check for shorts
Now check the EGT signal circuit for a short to ground or SIGRTN. Stay on the suspect sensor circuit and use the specified connector pins for that sensor. The resistance needs to be greater than 10K ohms. If it is not greater than 10K ohms, repair the short circuit, clear the PCM DTCs, and repeat the self-test. If that passes, turn the ignition on and check the signal circuit for a short to voltage at the specified pins. Any voltage present means repair the short circuit, clear the PCM DTCs, and repeat the self-test. For this P0545 path, if no voltage is present, continue with the EGT sensor and harness checks.
Check the EGT sensor reading
The next sensor check reconnects the EGT sensor connector and the PCM-E connector, then turns the ignition on and monitors the available EGT temperature PIDs. All PIDs may not be available on every truck, so work with what the scan tool supports. The decision point is whether any of those EGT PIDs displays a reading higher than 1,100°C (2,012°F). If one does, the directed repair is a new Exhaust Gas Temperature sensor, followed by clearing the PCM DTCs and repeating the self-test. If none of the readings are higher than that, continue into the comparison checks.
Look for an intermittent short or open
For the intermittent check, reconnect the EGT sensor connector and the PCM-E connector, turn the ignition on, and monitor the available EGT temperature PIDs. Record the EGT values. Set the lower scan tool limit to 30°C (54°F) below the lowest reading sensor, and set the upper limit to 20°C (36°F) above the highest reading sensor. Then do a thorough wiggle test on the suspect EGT harness from the PCM connector out to the EGT sensor connector, and tap lightly around the sensor to simulate road shock. If the EGT values move outside that limit range, repair as needed, clear the PCM DTCs, and repeat the self-test. If they stay inside the limits, continue. One important handling note: if any EGT connector was disconnected with the ignition on and the engine off, reconnect it, turn the ignition off for 30 seconds, and do not crank or start until that 30 seconds has passed. Skipping that step may cause a 60 minute no crank, no start condition and an FMEM condition.
Compare cold EGT readings to ambient
Next is the cold comparison. Turn the ignition off and allow the exhaust system temperature to stabilize to ambient temperature for a minimum of 6 hours. Then reconnect the EGT sensor connector and PCM-E connector if needed, turn the ignition on, and monitor the EGT temperature PIDs along with ambient air temperature. The check point is whether all EGT readings are within 20°C (36°F) of ambient temperature. On this path, whether they are within that range or not, the next move is still the response test. The comparison tells you if a sensor is offset cold, but it does not end the diagnosis by itself. Keep the same 30 second ignition-off handling rule in mind after any EGT connector disconnection before attempting to start the engine.
Check sensor response against the rest of the EGT stream
Now check the EGT sensor response. Let the exhaust temperature stabilize. After an 8 hour ignition OFF soak time, identify the suspect sensor by comparing the EGT temperature readings to ambient; the EGT temperature differences should be within 40°C (72°F). Then connect the EGT sensor connector, start the engine, and monitor the EGT temperature PIDs. Run the engine at 1,500 RPM for 10 minutes. At the end of the 10 minutes, record the EGT values. Turn the ignition off, let the exhaust system stabilize for a minimum of 10 minutes, then record the EGT values again. Compare the readings to each other in both captures. The decision is whether each EGT sensor PID value is within 40°C (72°F) of the next sensor in line with exhaust flow. If the readings are not within that range, install a new Exhaust Gas Temperature sensor, clear the PCM DTCs, and repeat the self-test. If the readings are within range on this P0545 path, move to the PCM connector and module operation check.
Confirm the suspect sensor voltage behavior
There is also a voltage PID disconnect check used to determine the suspect EGT sensor. With the ignition on, access the PCM and monitor the available EGT voltage PIDs. Then disconnect the suspect EGT sensor harness connector. The decision point is whether the suspect EGT sensor PID value is greater than 4.7 V when disconnected. If it is greater than 4.7 V, check for a loose connection and damaged or corroded terminals, wiggle the harness while trying to recreate the concern, and repair as needed. If no connector or harness concern is found during that inspection, the directed repair is a new EGT sensor, followed by clearing the PCM DTCs and repeating the self-test. If the value is not greater than 4.7 V when disconnected, continue to the PCM operation check.
Check PCM connector condition and verify the repair
Keep verification separate from the circuit testing. For the PCM operation check, disconnect all PCM connectors and inspect for pushed-out pins and corrosion. Reconnect all PCM connectors and make sure they seat correctly, then verify whether the concern is still present. If the concern is still present, the directed repair is a new Powertrain Control Module with the required RVC generation. If the concern is gone, the system is operating correctly at this time, and the fault may have been caused by a loose or corroded connector. After any repair in this path, clear the PCM DTCs, repeat the self-test, and verify the repair by confirming P0545 stays gone. The takeaway: prove the circuit first, catch intermittents with live EGT data, compare the sensor against ambient and the rest of the exhaust stream, and only then move to module-level decisions. For more diagnostic training, visit stepdiagnostics.com.
Final check
This code is often best approached as an electrical sensor-circuit diagnosis first, then an EGT response comparison, and only then a module-side check if the earlier tests pass.
For more guided automotive diagnostics, visit STEP Diagnostics.
