P242DExhaust Gas Temperature Sensor Circuit High (Bank 1 Sensor 3)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P242D is the mirror case of P242C: bank 1 probe 3 reports more than its plausible maximum, typically because the circuit is open or touches a supply. GM's 2020 diesel tables trigger above 900 Ω after 10 of 20 samples, the 3.0 L LZO above 100 MΩ for an analog probe or above 1,289.85 °C for a digital one; both tables rate it Type A, so the MIL comes on in the first faulty trip. Ford's 2023 diesels react to more than 2.66 V. Deutz describes P242D-00 as a short to battery. Stellantis lists P242D among the exhaust sensor codes of the 2025–2026 Ram 2500/3500 and asks technicians to check battery voltage first and to identify each sensor by name rather than number. Usually the fix is a connector, a harness repair or the sensor itself.
- What you may notice
- MIL on in the first faulty trip (GM Type A)
- Sensor 3 shows an implausibly high temperature or the maximum value
- Regeneration and DEF dosing restricted
- Likely causes
- LikelyOpen signal or return wire, broken by heat or vibration
- PossibleConnector unplugged or corroded
- PossibleSignal wire shorted to a supply voltage
- RareLow battery voltage during diagnosis (Ram 2025–2026 note)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €40 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.