Powertrain, generic (extended)

P242A Exhaust Gas Temperature Sensor Circuit (Bank 1 Sensor 3)

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modeNo

P242A is the general circuit code for the third exhaust temperature probe on bank 1. Where that probe sits is up to each manufacturer: VW counts it behind the oxidation catalyst on the 2014 Touareg TDI, Deutz places it downstream of the SCR catalyst on its EMR L1 controller. VW sets P242A once the signal voltage climbs above 2.61 V, which fits an open circuit. Deutz splits the code by failure type, -13 for an open, -F0 for a ground fault and -1C for a supply out of range. Ford's 2023 diesels give the number a different job: a probe that strays more than 80 °C from its modelled value for 20 s within one trip. Dedicated low and high faults go to P242C and P242D. Without a trustworthy reading the ECM usually suspends regeneration or DEF dosing.

Likely causes

Open circuit or corroded terminal in the sensor connector or harness near the exhaust

Exhaust temperature sensor 3 failed internally

Ground fault or sensor supply out of range (failure types -F0/-1C on Deutz)

On Ford diesels, sensor reading deviating from the exhaust temperature model

Symptoms

MIL on
Particulate filter regeneration or DEF dosing suspended
Implausible or missing value for sensor 3 in the scan tool

Repair estimate

DifficultyMediumDIY possible

Parts and labour€40–350

Time0.3–1.5 h

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

Parts involved

egt sensor b1s3

References: static.nhtsa.gov, serdia.deutz.com, fordservicecontent.com.