Intake System, Checking For Leaks (False Air)

Intake System, Checking For Leaks (False Air)

Checking with engine leak detection spray

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

Test requirements
- Vacuum reservoir in intake manifold must be properly sealed, checking.
- For vehicles with automatic transmission, selector lever must be in -P-.
- Coolant temperature must be at least 80 degrees C, Diagnostic mode 1: Check measured values; PID 5 ($5), Coolant temperature.

Test sequence
Observe safety precautions.
Observe rules for cleanliness.

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.
- Start engine and let run at idle.
- Under address word 33, select "Diagnostic mode 1: Check measured values."
- Select the following measured values:
- PID 6 ($6): Short time gasoline-air ratio bank 1
- PID 8 ($8): Short time gasoline-air ratio bank 2
- PID 12 ($C): Engine rotations per minute (RPM)

- Observe the short time gasoline-air ratio bank 1 and 2 as well as the engine speed.
- Spray intake system parts with engine leak detection spray in a systematic manner.

If engine speed drops or if the short-term gasoline-air ratio changes:
- End diagnosis and switch ignition off.
- Check sprayed part of intake system for leaks, and repair the malfunction.
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes