U3576 code meaning
Stack Differential Pressure Sensor Circuit
Network system Generic code U35xx codes Check engine light
What U3576 means
U3576 is set when the stack differential pressure sensor delivers no signal, a shorted one or one outside its valid range. The title leaves open which two pressures it compares. In a GM patent such a sensor is plumbed between anode and cathode side, as the anode is normally kept slightly above the cathode. GM also uses it ahead of start-up, with the cathode still at ambient pressure, to verify the anode pressure sensor: ambient plus differential reading should match the anode value. Ford keeps the difference across the membrane within a tolerance of around 600 mbar, may shut the system down when it is breached and heats such sensors so that ice cannot blind them. No maker documents U3576 publicly. Expect a warning, reduced power or no start; anode inlet pressure is U3566/U3567.
U3576 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyHard
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U3576
- Fuel cell system warning, MIL on
- Reduced power or fuel cell system shuts down
- No start, especially after a cold night
Common causes of U3576
- Most likelyOpen, short or corrosion in wiring or connector of the differential pressure sensor
- PossibleWater or ice in the sensor ports or a failed sensor heater
- PossibleDifferential pressure sensor faulty internally
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Stack differential pressure sensorSensor wiring
What each part of U3576 means
| U | Network system: communication between the control modules (CAN bus). |
| 3 | Reserved range, usually generic. |
| 76 | The exact fault in that area. |
What to do next
- Note U3576 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 U3576
What does U3576 mean?
U3576 means "Stack Differential Pressure Sensor Circuit". U3576 is set when the stack differential pressure sensor delivers no signal, a shorted one or one outside its valid range. It is a generic code, so it means the same on every make.
Is it safe to drive with U3576?
Drive gently and only to a workshop. With U3576 the car can go into limp mode (reduced power) to protect itself.
Will U3576 fail an emissions test?
U3576 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 U3576 to fix?
Difficulty: hard. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U3576 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.