P0545: Exhaust Gas Temperature Sensor Circuit Low — Bank 1 Sensor 1
What to do
Driveable, but regeneration may be inhibited on a diesel. Mention any recent exhaust work — these leads are easily damaged during it.
What this code means
The bank 1 exhaust gas temperature signal is below its plausible range. Unplugging the sensor and watching which way the reading moves identifies how this circuit behaves with an open, which tells you immediately whether you are looking at a short or a break.
These sensors mount directly in the exhaust stream and their leads are routinely damaged during other exhaust work, so recent history matters — a fault appearing straight after a turbo, filter or manifold job points at a disturbed lead rather than a coincidence.
Likely causes
Start here
- Signal wire shorted to ground · moderate
- Faulty exhaust gas temperature sensor · moderate
- Damaged wiring harness near exhaust heat · moderate
Less common
- Corroded or loose connector · easy
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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- The car — make, model, year and engine. The same fault behaves differently on each.
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