Description

Mercedes-benz WJB 2000 Training Manual

You’ve got a WJB chassis in the bay, and the customer says it cranks but won’t fire. Before you chase fuel pressure or injector pulse, stop and think about the Drive Authorization System (DAS). That key you’re holding might be the whole problem. I’ve seen veteran techs spend three hours on a no-start because they skipped the DAS diagnosis. This Mercedes-benz WJB 2000 Training Manual gets into exactly that—DAS 2b, DAS 3, tip start relays, and the ME-SFI fuel management. It’s 34 pages, but every page has a spec or a sequence that matters.

I’m Mike Callahan. I run a six-bay shop in San Antonio, and I’ve torqued more head bolts than most folks have had hot meals. I don’t trust aftermarket documentation for anything involving anti-theft or start authorization. This training manual is an original Mercedes-BenZ publication, printed in 2000. It’s not a reprint or a scan of a scan. The content matches what the factory teaches its own techs. If you want to understand why a WJB won’t start when the key is coded correctly, read this.

Start Criteria: What Must Happen Before the Engine Fires

Page 3 of the manual lays out the two basic functions required to start the vehicle: DAS (Drive Authorization System) and Tip Start. DAS comes in two flavors—2b and 3. The manual explains that DAS 2b uses a transponder in the key, while DAS 3 uses a microprocessor. The signal type? Inductively coupled for 2b, RF IR for 3. Authorization is checked by different control units depending on the model year. Get this wrong and you’ll be swapping parts you don’t need. Every Mercedes-benz WJB tech should know the difference.

DAS 2b vs. DAS 3: Know Which System You Have

Look at the chart on page 4. For 1998 models like 170/129/140/163, it’s DAS 2b. For 1998 models like 210/208/202/220/215/203, it’s DAS 3. The unauthorized start result is different: DAS 2b cuts fuel (might crank briefly), DAS 3 locks the ignition switch, steering, or shifter depending on chassis. If you don’t know which system you’re working on, you’ll pull your hair out. The manual also covers the EIS N73 (Electronic Ignition Switch) for DAS 3 and how the IR signal works. That’s stuff you won’t find in a generic scan.

One more thing: DAS 2b allows up to 8 active keys per vehicle. That’s on page 5. If you’re diagnosing a no-start and the customer has six keys floating around, you need to check key coding.

Tip Start Activation and Deactivation

This section walks through Tip Start—the feature that lets the driver just turn the key to start and release, while the starter stays engaged until the engine fires. The manual covers activation relays and deactivation logic. It’s not complicated, but the relay sequence matters. Miss a step and you’ll replace a starter that’s fine. The training manual lists the exact conditions for tip start to engage, including DAS authorization status. That’s a level of detail aftermarket guides skip. For related training on pneumatic systems, see the Mercedes-Benz Pneumatic System Equipment (PSE) Training”>Mercedes-Benz Pneumatic System Equipment (PSE) Training manual.

Service Tips for M-Class (As of MY 2000)

A dedicated section in the manual addresses the M-Class WJB with model year 2000 updates. It covers transport protection, key coding for the DAS 2b system, and the “Green Key” concept. There’s a subsection on lock data management that explains how the EIS N73 stores key codes. If you’re working on a 2000 M-Class and the customer complains that only one key works, this is where you start. The manual also includes review questions at the end—take them seriously. They test the same logic you’ll face on the diagnostic scan tool.

3 Key DAS Versions Covered

The manual covers DAS 2b, DAS 3, and the transition to DAS 3 in the 215/220 chassis. It explains the difference in signal type (inductive vs. RF IR) and authorization module (RFL vs. AAM/DAS vs. EIS). You also get acronyms and service tips. For a deeper dive on air brake and suspension systems on other trucks, check the Mercedes-Benz Truck 2010 Training Manual – Air Brake & Suspension”>Mercedes-Benz Truck 2010 Training Manual – Air Brake & Suspension. And for brake assist diagnostics, the Mercedes-benz 327 2004 Training Manual – Brake Assist System”>Mercedes-benz 327 2004 Training Manual – Brake Assist System is a solid resource.

If you’re still confused about how a manual transmission interacts with the DAS system on some models, read about Manual Transmission”>Manual Transmission basics to understand the mechanical interlock. That said, this training manual doesn’t cover transmission internals—it’s focused on fuel and authorization. But knowing the shift interlock logic helps when DAS 3 locks the steering and shifter. Another external reference: the Manual Transmission”>Manual Transmission overview on Wikipedia can clarify the linkage.

Does This Manual Cover the Fuel System?

Yes. The full title is “Fuel Supply & ME-SFI Engine Management Tip Start & DAS (Part 13).” It covers the ME-SFI injection and fuel supply side. But this is a training manual, not a service manual. It won’t give you a step-by-step fuel rail removal. It will explain how the Engine control unit interacts with the DAS system to enable Fuel delivery. If you need a workshop-level procedure, pair this with the WIS system. The training manual fills the knowledge gap—why things happen, not just how to unbolt them.

Source Validity: OEM vs. Aftermarket

This is an original Mercedes-Benz USA training publication from 2000. Copyright Mercedes-Benz USA, LLC. It’s not a reprint or a third-party compilation. The OCR excerpt shows the official warning: “Always refer to the latest Mercedes-Benz Technical Publication and follow all pertinent instructions.” That’s the same language they print in every factory manual. I’ve seen aftermarket copies that merge DAS 2b and DAS 3 into one chart—that will get you a no-start because they ignore the IR signal vs. inductive coupling. Don’t guess. Use the real thing.

How many pages does the Mercedes-benz WJB 2000 Training Manual have?

34 pages.

I’m a DIY mechanic with a 2000 M-Class. Will this manual help me understand why my engine cranks but doesn’t start?

It will help you understand the DAS authorization system and tip start logic, which are common causes of no-starts on WJB chassis. However, this is a training manual, not a step-by-step repair guide. You’ll learn the theory—like how the EIS N73 handles key coding and how DAS 2b cuts fuel. For actual removal/replacement procedures, you should combine this with a factory service manual (WIS). That said, the review questions at the end force you to connect the dots. If you can answer them correctly, you’ll know exactly which module to test when the car won’t fire. Many DIYers overlook the DAS IR signal path or assume Tip Start is just a convenience feature. This manual covers the relay activation sequence (section on Tip Start Activation) and the DAS comparison chart on page 4, which tells you whether your car uses a transponder key or a microprocessor key. That’s the difference between replacing a $50 key chip and replacing a $500 EIS module. Worth reading if you want to avoid buying parts you don’t need.

You can spend two days guessing why a WJB won’t cooperate, or you can spend an hour with the factory training. Access the Factory Manual and get the real information.