P049A code meaning
EGR B Flow
Powertrain system Generic code P04xx codes Check engine light
What P049A means
Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx. Circuit B is the second EGR path; on diesels with two circuits it is the low-pressure EGR, which takes exhaust after the particulate filter and feeds it in before the turbo compressor (GM diesels 2016–18, FCA's 2.2 and 3.0 diesels). P049A is the general flow fault of circuit B, used where the module does not separate too little from too much; CARB requires low and high flow to be detected, mostly by comparing air mass, manifold pressure or lambda with a model. No manufacturer document available to us uses P049A – GM has only position and actuator codes for its low-pressure EGR, FCA uses P049B. Low-pressure EGR is then switched off.
P049A at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyHard
- Typical labor1 to 5 hours
- Clears after repairAfter a drive cycle
Symptoms of P049A
- Check engine light on
- EGR switched off, usually no noticeable change
- Higher NOx
Common causes of P049A
- Most likelyLow-pressure EGR valve sooted or sticking
- PossibleLow-pressure EGR cooler or line blocked or leaking
- PossibleFlap creating the pressure difference faulty
- PossibleSensors (air mass, pressure difference, position sensor B) implausible
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Low pressure EGR valveLow pressure EGR coolerEGR b circuitEngine control module
What each part of P049A 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). |
| 9A | The exact fault in that area. |
What to do next
- Note P049A 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 P049A
What does P049A mean?
P049A means "EGR B Flow". 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 P049A?
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 P049A fail an emissions test?
Yes, it can. P049A 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 P049A to fix?
Difficulty: hard. A typical repair takes 1 to 5 hours of work. This is a job for a workshop.
Will P049A 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.