Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic tester, connecting
Special tools, testers and auxiliary items required
- Vehicle Diagnosis Service Syst. VAS5052 with Diagnostic Cable (5 M) VAS5052/3 or equivalent.
Test requirements
- The fuses for the engine electronics OK..
- The Ground (GND) connections at the engine and transmission OK.
- The battery voltage at least 12.5V.
- The parking brake engaged.
- The selector lever of the automatic transmission in position "P" or "N".
- All electrical consumers switched off (radiator fan must NOT run during test).
- The A/C switched off.
- Test and measuring equipment must always be secured to the rear seat and be operated from there by a second person.
- If test and measuring equipment is operated from the front passenger seat, the person seated there could be injured in the event of an accident involving deployment of the passenger-side airbag.
Procedure
- Switch ignition off.
- Connect Vehicle Diagnosis Service Syst. VAS5052 with Diagnostic Cable (5 M) VAS5052/3 or equivalent to Data Link Connector (DLC) - arrow -.
- Switch ignition on or start engine.
- Select diagnostic function "33 - OBD", several diagnostic modes can be selected.
The following diagnostic modes monitor all components and systems which influence the emission quality.
| Selectable diagnostic modes | Refer to | Requirements | ||||||
|---|---|---|---|---|---|---|---|---|
| Ignition on, engine standing | Engine running at idle | Vehicle in drive mode | ||||||
| Mode 1: | Obtain data | → Diagnostic Mode 1: Obtain data | Yes | Yes | Yes | |||
| Mode 2: | Obtain operating conditions | → Diagnostic Mode 2: Obtain operating conditions | Yes | Yes | Yes | |||
| Mode 3: | Interrogating DTC memory | → Diagnostic Mode 3: Interrogating DTC memory | Yes * See note | Yes | Yes | |||
| Mode 4: | Reset/delete diagnostic data | → Diagnostic mode 4: Reset/delete diagnostic data | Yes | Yes | Yes | |||
| Mode 5: | Obtain lambda test results | → Diagnostic Mode 5: Check lambda test results | Yes | Yes | Yes | |||
| Mode 6: | Checking test results of components that are not continuously monitored | → Diagnostic Mode 6: Checking test results of components that are not continuously monitored | No | Yes | Yes | |||
| Mode 7: | Checking test results of components that are continuously monitored | → Diagnostic mode 7: Check test results of components that are continuously monitored | Yes * See note | Yes | Yes | |||
| Mode 8: | Tank leak test | → Diagnostic Mode 8: Tank leak test | No | Yes | Yes | |||
| Mode 9: | Vehicle information | → Diagnostic mode 9: Vehicle information | Yes | No | No | |||
*If the engine does not start, crank engine using the starter for at least 5 seconds, do not switch the ignition off afterward under any circumstances.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.