What does it mean?
P1188 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Throttle Inlet Pressure Sensor Signal Range/Performance .
Symptoms
- Check engine light on
- Reduced boost and poor acceleration, sometimes with limp mode
- Hesitation and flat spots when the engine comes on boost
- Fuel consumption higher than usual
- Hissing or whistling from the charge air pipework if a leak is present
- Irregular idle in some cases
Likely causes
- Sensor element drifted with age or contaminated by oil mist from the crankcase ventilation system
- Blocked, cracked or oil-filled pressure reference hose
- Boost or charge air leak between the compressor and the throttle body
- Restricted air filter or a collapsed intake duct changing the real inlet pressure
- High resistance in the signal or ground circuit, corroded connector pins
- Charge air cooler leaking, so the pressure at the throttle inlet does not match expectation
- Rarely, a control module input or calibration issue
How to fix it
- With the ignition on and the engine off, compare this sensor's value with the barometric and manifold pressure readings; all should read close to atmospheric
- Watch the reading while driving and confirm it rises smoothly with boost
- Inspect the reference hose for oil, kinks, cracks and blockage
- Pressure test the charge air system to find leaks at pipes, clamps and the cooler
- Check the air filter and intake ducting for restriction or collapse
- Test the signal, reference and ground circuits for continuity and voltage drop, and inspect the connector
- Replace the sensor if it still disagrees with the reference readings after the plumbing and wiring test good