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.
Medium severity. Can I keep driving?If the light is on steadily, take a highway drive or go to a repair shop soon. If the car is in limp mode or the light is flashing, do not push the engine.
Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank.
Symptoms
- Malfunction indicator lamp on
- Particulate filter regeneration postponed
- Temperature values of sensors 1 and 3 differ noticeably on a cold engine
Most 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
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P20E3 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 0: Subsystem depends on the code range
- E3: Specific fault in that system
Frequently asked questions
Can I keep driving with code P20E3?
If the light is on steadily, take a highway drive or go to a repair shop soon. If the car is in limp mode or the light is flashing, do not push the engine.
What causes code P20E3?
The most common causes are: 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.
Related codes
- P20E2Exhaust Gas Temperature Sensor 1/2 Correlation (Bank 1)
- P20E4Exhaust Gas Temperature Sensor 2/3 Correlation (Bank 1)
- P2080Exhaust Gas Temperature Sensor Circuit Range/Performance (Bank 1 Sensor 1)
- P242BExhaust Gas Temperature Sensor Circuit Range/Performance (Bank 1 Sensor 3)
- P24C2Exhaust Gas Temperature Measurement System - Multiple Sensor Correlation Bank 1
- P242AExhaust Gas Temperature Sensor Circuit (Bank 1 Sensor 3)
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.