P11C5
LowP11C5 — EVAP System Pressure Differential Sensor: Low Signal in Circuit
Description
What the Code Means
P11C5 sets when the engine control module sees low voltage in the pressure differential sensor circuit of the evaporative emissions (EVAP) system. The sensor monitors pressure inside the EVAP system and reports it to the engine control module.
A low signal can come from a faulty sensor, wiring or connector problems, or an EVAP system leak that puts pressure outside the expected range.
Symptoms
Symptoms
- Check Engine light is on;
- possible fuel smell;
- EVAP system test fails.
Causes and fixes
Diagnosis and Repair
- Check the sensor wiring and connector: corroded contacts, damaged insulation, and a loose connector.
- Read sensor voltage with ISTA and compare it to the reference values.
- If the sensor is confirmed faulty, replace it. OEM part number:
16137275075. - Run a smoke test on the EVAP system for leaks — a leak alone can cause low readings.
A common diagnostic mistake is replacing the sensor without checking the wiring and running a leak test first: the low signal may not come from the sensor.
Possible secondary damage
Secondary Issues
- fuel vapor may escape into the atmosphere;
- no mechanical damage to the engine;
- if you ignore the code, the car won't pass an emissions test.