P245B code meaning
EGR Cooler Bypass Control Circuit Range/Performance (Bank 1)
Powertrain system Generic code P24xx codes Check engine light
What P245B means
P245B is set when the bank 1 bypass is electrically intact but does not reach or hold the commanded position, or when switching it has no visible thermal effect. GM's 2017 Duramax with a position-controlled DC-motor flap compares setpoint and feedback; a tracking error above 16 % in 1280 of 1600 samples, with a steady setpoint, coolant over 70 °C and outside air above minus 23 °C, sets a Type B fault, and P24A5 follows if the flap is then found stuck. Ford's 2023 diesels, the 6.7 L and the 3.0 L, run an intrusive test once per trip: the flap is moved, and if the gas temperature after the cooler changes by less than 3 °C per second, P245B is logged. Carbon on the flap shaft, a worn linkage, a weak vacuum supply or a position sensor fault are typical causes. Pure circuit faults are P245A, P245C and P245D.
P245B at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 4 hours
- Clears after repairAfter a drive cycle
Symptoms of P245B
- Malfunction indicator lamp on
- Longer warm-up or higher NOx when the bypass stays in one position
Common causes of P245B
- Most likelyBypass flap or shaft sticking from carbon deposits
- PossibleBypass position feedback inaccurate
- PossibleWeak vacuum supply or leaking hose on vacuum-operated bypass
- Less likelySlow EGR temperature sensor after the cooler
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
EGR cooler bypass valve b1
What each part of P245B 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). |
| 5B | The exact fault in that area. |
What to do next
- Note P245B 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 P245B
What does P245B mean?
P245B means "EGR Cooler Bypass Control Circuit Range/Performance (Bank 1)". P245B is set when the bank 1 bypass is electrically intact but does not reach or hold the commanded position, or when switching it has no visible thermal effect. It is a generic code, so it means the same on every make.
Is it safe to drive with P245B?
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 P245B fail an emissions test?
Yes, it can. P245B 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 P245B to fix?
Difficulty: medium. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will P245B 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.