Intake Air System, Checking For Leaks (Unmetered Air)

Checking Intake System For Leaks (unmetered Air)

Checking with engine leak detection spray

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

Test requirement
- Coolant temperature must be at least 80°C, Diagnostic mode 1: Check measuring values; PID 5, Coolant temperature. Diagnostic Mode 1: Check Measured Values

Test sequence

NOTE: The negative pressure in the intake system sucks in the leak detection spray with the unmetered air. Leak detection spray decreases ignition quality and performance 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: Checking measured values."

- Select the following measured values:
PID 06: Short time gasoline-air ratio bank 1
PID 12: Engine rotations per minute (RPM)

- Observe the short time gasoline-air ratio bank 1 and 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 eliminate the error.
- 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