P046E code meaning
EGR Sensor B Circuit Range/Performance
Powertrain system Generic code P04xx codes Check engine light
What P046E means
Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx. Which part EGR sensors A and B are depends on the maker: sensor A is usually the position sensor of EGR valve A; GM's Duramax diesels of 2017/18 use sensor B for the coolant temperature sensor at the inlet of the high-pressure EGR cooler, FCA for the position sensor of the low-pressure valve. P046E means the signal of sensor B is valid but implausible. On GM's Duramax diesels, where it is the cooler inlet coolant temperature, the module compares it at a cold start after at least 8 hours off with two charge air temperature sensors; a deviation above 10 °C sets the code once per trip, MIL after two trips. A substitute value is then used and the EGR cooler check (P2457) is suspended.
P046E at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.5 to 1.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P046E
- Check engine light on
- Usually no change in driving
- EGR cooler check suspended
Common causes of P046E
- Most likelyTemperature sensor drifting
- PossibleContact resistance at the connector
- Less likelyReference sensor (charge air temperature) inaccurate without its own code
- Less likelyLow coolant or air at the sensor
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
EGR sensor bEGR cooler coolant temperature sensorSensor wiringEngine control module
What each part of P046E means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 6E | The exact fault in that area. |
What to do next
- Note P046E 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 P046E
What does P046E mean?
P046E means "EGR Sensor B Circuit Range/Performance". Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx. It is a generic code, so it means the same on every make.
Is it safe to drive with P046E?
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 P046E fail an emissions test?
Yes, it can. P046E 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 P046E to fix?
Difficulty: easy. A typical repair takes 0.5 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P046E clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.