Powertrain, generic · Vehicle speed, idle control and auxiliary inputs

P0545 Exhaust Gas Temperature Sensor Circuit Low Bank 1 Sensor 1

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

The exhaust gas temperature sensor is a thermistor in a voltage divider with the module's pull-up resistor; the first one (sensor 1) sits before the turbocharger, the oxidation catalyst or after it depending on the maker. Diesels use it for particulate filter regeneration and component protection; CARB names it explicitly as a monitored input. P0545 means the signal is below range: GM L5P below 142 Ω in 10 of 20 samples, GM LML below 0.65 V, Ford 6.7 L below 0.10 V for about 2 s, Saab 9-5 2.0 TiD below 0.1 V for 1 s. Usually a signal shorted to ground. GM USA uses two trips, GM Europe in the Saab one. The module uses a substitute value and blocks filter regeneration.

Likely causes

Signal line shorted to ground (chafed on the exhaust or bracket)
Sensor shorted internally
Connector damp or corroded
Engine module

Symptoms

  • Check engine light on
  • Particulate filter regeneration missing, filter warning
  • Possible power reduction

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–300
Time0.5–1.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

exhaust gas temperature sensorsensor wiringengine control module

Related codes

P0544P0546P2080P2081P0548P2032

References: fordservicecontent.com, gsi.ext.gm.com, gsi.ext.gm.com, saabwisonline.com.