Variable Induction System: Testing and Inspection

Diagnostic Procedures


Intake System, Checking for Leaks

Special tools, testers and auxiliary items required

• Engine leak detection spray G 001 800 A1

Test 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 P position.

• Coolant temperature must be at least 80 °C , Diagnostic mode 1: Check measured values; PID 5, Coolant temperature.

Test sequence

• 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: Checking measured values."

- Select the following measured values:

• PID 06: Short time gasoline-air ratio bank 1

• PID 08: Short time gasoline-air ratio bank 2

• PID 12: Engine rotations per minute (RPM)

• Bank 1 = Cylinder bank 1, in direction of travel, right.

• Bank 2 = Cylinder bank 2, in direction of travel, left.

- 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.

- Generate readiness code.