Powertrain, generic (extended)

P20E3 Exhaust Gas Temperature Sensor 1/3 Correlation (Bank 1)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P20E3 reports that exhaust temperature sensors 1 and 3 on bank 1 do not agree. In the usual diesel order, sensor 1 measures before the oxidation catalyst and sensor 3 after the particulate filter, so this pair brackets the whole aftertreatment line. No manufacturer documents this exact code publicly. Navistar's patent US7533519 explains the principle with sensors at the catalyst inlet, filter inlet and filter outlet: after a long stop all three must have cooled to almost the same value, and every pairwise difference is checked to expose a sensor stuck inside its range. Ford's 2023 diesels perform a comparable cold check (50 °C limit after 6 h off) but store P2080, P2084, P242B or P24C2 instead. CARB demands such plausibility checks for temperature sensors used by emission strategies. Expect the MIL; filter regeneration may be held back.

Likely causes

Sensor 1 or sensor 3 reading offset or responding sluggishly
Water or corrosion in the connector of the rear sensor
Exhaust leak near one sensor letting outside air cool its tip

Symptoms

  • Malfunction indicator lamp on
  • Particulate filter regeneration postponed
  • Temperature values of sensors 1 and 3 differ noticeably on a cold engine

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–400
Time0.5–2.5 h

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

Parts involved

exhaust gas temperature sensorwiring harness

Related codes

P20E2P20E4P2080P242BP24C2P242A

References: patents.google.com, fordservicecontent.com, law.cornell.edu.