Intake Air System, Checking For Leaks (False/Unmetered Air)

Checking Intake System For Leaks (False Air)

Checking with engine leak detection spray

Recommended special tools and equipment
- Engine leak detection spray G 001 800 A1

Requirements
- Parking brake must be engaged or else daylight driving lights will be switched on.
- For vehicles with automatic transmission, selector lever must be in position -P- or -N-
- Coolant temperature must be at least 80 degrees C. Diagnostic mode 1: Check measured values; PID 5, Coolant temperature. Diagnostic Mode 1: Check Measured Values

Work sequence

NOTE:
- Vacuum in the intake system sucks in the leak detection spray with false air. Leak detection spray decreases ignition quality of the fuel mixture. This causes a drop in engine speed and changes the value produced by the Heated Oxygen Sensor (HO2S).
- It is absolutely necessary to follow the safety precautions listed on the can.

- Connect diagnostic tester. Diagnostic Tester, Connecting
- Start engine and let run at idle.
- Under address word 33, select "Diagnostic mode 1: Check measured values."
- Select following measured values:
- PID 06: Short time gasoline-air ratio bank 1
- PID 12: Engine rotations per minute (RPM)
- Observe short time gasoline-air ratio bank 1 and engine speed.
- Spray intake system parts with engine leak detection spray in a systematic manner.

If engine speed drops or if short-term gasoline-air ratio changes:
- End diagnosis and switch ignition off.
- Check sprayed part of intake system for leaks, and repair malfunction.
- Erase DTC memory of Engine Control Module (ECM). Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes