U355B code meaning
Charge Air Cooler Outlet Pressure Sensor 2 Circuit
Network system Generic code U35xx codes Check engine light
What U355B means
U355B points to a circuit problem with pressure sensor 2 at the charge air cooler outlet. J2012 lists two at this spot, which points to a pair used for cross-checking; how a maker splits the roles is unpublished, and no public document uses U355B. A GM patent shows the principle: before start-up, while the compressor stands still and the cathode holds only atmospheric pressure, readings are compared, and a doubtful sensor is replaced by a value calculated from the remaining ones. Ford names a winter risk on the wet air side: water on a sensor diaphragm can freeze and give no or false output at a cold start, which may lead to a shutdown. Sensor 1 at the same spot is U355A. With only one valid sensor left, output may be limited.
U355B at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U355B
- Fuel cell system warning, MIL on
- Start refused or system shuts down shortly after a cold start
- Reduced power while only one pressure sensor is valid
Common causes of U355B
- Most likelyOpen, short or corrosion in wiring or connector of sensor 2
- PossibleCondensed water frozen on the sensor (occurs at cold start, may clear when warm)
- PossiblePressure sensor 2 faulty internally
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cac outlet pressure sensor 2Sensor wiring
What each part of U355B means
| U | Network system: communication between the control modules (CAN bus). |
| 3 | Reserved range, usually generic. |
| 5B | The exact fault in that area. |
What to do next
- Note U355B 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 U355B
What does U355B mean?
U355B means "Charge Air Cooler Outlet Pressure Sensor 2 Circuit". U355B points to a circuit problem with pressure sensor 2 at the charge air cooler outlet. It is a generic code, so it means the same on every make.
Is it safe to drive with U355B?
Drive gently and only to a workshop. With U355B the car can go into limp mode (reduced power) to protect itself.
Will U355B fail an emissions test?
U355B is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U355B to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U355B clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.