Network, generic (extended)

U3567 Anode Inlet Pressure Sensor 2 Circuit

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

U3567 belongs to the second pressure sensor at the anode inlet. Its signal carries safety weight: GM uses anode pressure to catch an injector stuck open, then shuts the tank valves, opens the anode bleed valve, lifts cathode pressure with compressor and backpressure valve and opens the cathode bypass so hydrogen in the exhaust stays diluted. Another GM patent treats a gap of more than a calibrated margin, typically 3 kPa, between actual and desired pressure as an injector fault. Sensors in this wet zone can ice up, so GM checks the anode sensor before start against ambient pressure plus the anode-to-cathode differential. A second sensor allows a similar comparison while driving. No maker publishes U3567. Expect a warning; with sensor 1 as the only source, power may be reduced. Sensor 1 is U3566.

Likely causes

Open, short or corrosion in wiring or connector of sensor 2 at the stack
Anode inlet pressure sensor 2 faulty internally
Water in the connector, fault mainly after frost

Symptoms

  • Fuel cell system warning, MIL on
  • Often no noticeable change while sensor 1 still works
  • Reduced power

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€150–1,000
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

anode inlet pressure sensor 2sensor wiring

Related codes

U3566U3565U3576U3568

References: patents.google.com, patents.google.com, patents.google.com.