Checking Intake Air System For Leaks (Unmetered or False Air)

Intake System For Leaks (False Air), Checking

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

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 reduction in engine speed and a sharp increase of CO content.
- It is absolutely necessary to follow the safety precautions listed on the can.

Test requirements:
- Coolant temperature at least 80 degrees C see "Mode 1: Check measuring values "; "PID 05: Coolant temperature". Mode 1: Check Measured Values
- Parking brake engaged.
- Selector lever of automatic transmission in position "P" or "N".
- Ignition switched off.

Test sequence
- Connect diagnostic tester.
- Start engine and let run at idle.
- In diagnostic function "33 - OBD", select "Mode 1: Checking measured values."

NOTE: Bank 1 = cylinder bank 1 in direction of travel, right; Bank 2 = cylinder bank 2 in direction of travel, left.

- Select the following measured values:







- 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.

Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1. Check DTC memory see "Mode 3: Check DTC memory". Mode 3: Check DTC Memory
2. If necessary, erase DTC memory see "Mode 4: Reset/erase diagnostic data". Mode 4: Reset/Erase Diagnostic Data
3. Generate readiness code. Readiness Code, Generating

- End diagnosis and switch ignition off.