2017–2024 Mercedes-Benz E-Class

2017-2024 Mercedes-Benz E-Class — Check Engine Light / OBD2 Diagnosis

By Ray Delgado ✓ Certified Mechanic · Published Sep 21, 2026 · Updated Oct 22, 2026

🔧 Easy 15-30 minutes $25 DIY

Save $115 by doing it yourself! Shop cost: $140

Quick answer: Check Engine Light / OBD2 Diagnosis on a 2017–2024 Mercedes-Benz E-Class is rated Easy and takes about 15-30 minutes. You'll need 2 tools for this job, and parts cost about $25. This guide walks you through the full job step by step, including the mistakes to avoid.

Quick Video Tutorial

Parts You Need

Total Cost

$25.00

Part Name	Part Number	Price	Buy
OBD2 scanner	—	$25.00	Amazon

About prices: shown prices are typical retail averages and change frequently; cheaper alternatives may be available. Confirm the current price before buying.

💡 Pro tip: Order all parts at once to save on shipping

Step-by-Step Instructions

Follow these steps carefully

Read the lamp and dash messages

Note turbo lag, chain rattle on startup, rough idle, or overheating — they decide whether you drive gently to a scanner or stop and call a tow. Some faults on this car also need factory software, so set expectations before diving in.

Plug into the diagnostic connector

Push the scanner plug straight in until it seats, then ignition ON without starting and confirm the tool links and shows live data. If there's no link, try another adapter and check the relevant fuse.

🔧 Mechanic's note — Tom Becker

The generic scanner gets you the engine codes, but the body and chassis codes live behind Mercedes software. I scan with what I have first — and I stop when the code I need isn't in the list, instead of guessing.

Scan codes, freeze-frame, and live PIDs

Run a full scan and log confirmed, pending, and permanent codes with freeze-frame (RPM, load, coolant temp, speed). Add live boost pressure, cam-versus-crank data, fuel trims, and coolant temperature. Don't clear codes yet.

Inspect the systems the codes name

For P0299 on the 2.0L, inspect the turbo wastegate linkage for sticking and the charge-air hoses for leaks before suspecting the turbo itself. For misfires, inspect coils and plugs. For EVAP codes, tighten the fuel cap and inspect vapor lines.

🔧 Mechanic's note — Ray Delgado

On P0299 I check the wastegate linkage by hand first — a stuck wastegate arm is free to find and fixes the underboost without a turbo. The expensive guess is replacing the turbo; the cheap diagnosis is wiggling the linkage.

Fix, clear, and verify over a drive cycle

Repair the verified cause, then clear codes with the scanner. Drive normally for several days with full warm-up cycles and mixed city/highway miles so the monitors complete, then rescan and confirm no codes return and monitors read complete.

All Done!

Test your repair before closing everything up. If something doesn't work right, double-check your steps.

⚠️ Common Mistakes to Avoid

• Replacing parts based on a code without checking wiring, connectors, or vacuum leaks
• Clearing codes before recording confirmed, pending, and permanent codes
• Using a scanner that cannot communicate with the vehicle protocol
• Treating a stored code as proof that the named sensor itself failed

Tools You'll Need

OBD-II scanner compatible with the vehicle Flashlight Notebook or phone for codes and freeze-frame data Safety glasses

Related Trouble Codes

P0300 Random/Multiple Cylinder Misfire Detected P0301 Cylinder 1 Misfire Detected P0171 System Too Lean (Bank 1) P0174 System Too Lean (Bank 2) P0562 System Voltage Low P0302 Cylinder 2 Misfire Detected P0303 Cylinder 3 Misfire Detected P0304 Cylinder 4 Misfire Detected

⚠️ Safety First!

• Informational DIY. EZ Car Fix is not a shop.
• A flashing check-engine light can indicate a damaging misfire; reduce load and seek professional service promptly.
• Never work under a vehicle supported only by a jack.
• Do not clear codes before recording them and the freeze-frame data.