P242D code meaning
Exhaust Gas Temperature Sensor Circuit High (Bank 1 Sensor 3)
Powertrain system Generic code P24xx codes Check engine light
What P242D means
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.
P242D at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P242D
- 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
Common causes of P242D
- Most likelyOpen signal or return wire, broken by heat or vibration
- PossibleConnector unplugged or corroded
- PossibleSignal wire shorted to a supply voltage
- Less likelyLow battery voltage during diagnosis (Ram 2025–2026 note)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Egt sensor b1s3
What each part of P242D means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 2D | The exact fault in that area. |
What to do next
- Note P242D and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P242D
What does P242D mean?
P242D means "Exhaust Gas Temperature Sensor Circuit High (Bank 1 Sensor 3)". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P242D?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P242D fail an emissions test?
Yes, it can. P242D is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P242D to fix?
Difficulty: medium. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P242D clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.