OM612 Injector Problems – Symptoms, Causes & Fixes

Engine: OM612 11 compatible injectors From £100

Common Injector Failures on the OM612

The OM612 engine uses high-pressure common rail diesel injection. Over time, injector nozzles wear, seals degrade, and internal components lose calibration. This leads to a range of drivability symptoms that worsen if left unaddressed. We stock 11 tested replacement injectors for this engine from Bosch.

Vehicles fitted with the OM612 include models from Mercedes. If you are experiencing any of the symptoms below, your injectors may need testing or replacement.

Symptoms of Injector Failure

Related Fault Codes

P0201 P0202 P0203 P0204 P0263 P0266 P0269 P0087 P0089 P0300

How to Test OM612 Injectors

Leak-off test: Connect clear hoses to the injector return lines and compare fuel volumes at idle. The injector returning the most fuel is likely worn.

Correction values: Use a scan tool to read injector correction (IMA) values. Readings beyond ±3 mg/stroke indicate wear.

Resistance check: Measure resistance across the injector connector pins with a multimeter. Compare to manufacturer specs.

Complete Testing Guide Leak-Off Test Guide

OM612 Injector Replacement Cost

Parts (per injector)

£100–£240

Labour

£150–£400

Total (per injector)

£250–£640

Full replacement cost guide

Compatible Injectors for the OM61211 found

Most Common Injector Part Numbers for OM612 Engine

Related Cross Reference Numbers for OM612

0445110176 0445110177 0986435111 0986435112

Vehicles Using the OM612 Engine

Mercedes E CLASSOM612

Mercedes SPRINTEROM612

Mercedes C CLASSOM612

Mercedes VITOOM612

Mercedes A-CLASSOM612

Mercedes VIANOOM612

Related Engine Codes

NCV3 OM607 OM608 OM626 OM628 OM629

Frequently Asked Questions

What are common injector problems on the OM612 engine?

The OM612 engine commonly suffers from injector seal failure, nozzle wear causing poor spray patterns, and back-leak issues. Symptoms include rough idle, black or white exhaust smoke, hard starting, and increased fuel consumption. These issues typically appear after 100,000–150,000 miles.

How much does it cost to replace injectors on a OM612 engine?

A remanufactured injector for the OM612 engine typically costs £100–£240 per injector. Labour adds £150–£400 depending on accessibility. We found 11 compatible injectors for this engine.

Which vehicles use the OM612 engine?

The OM612 engine is found in vehicles from Mercedes. Common models include Mercedes A-CLASS, Mercedes B-CLASS, Mercedes C CLASS, Mercedes E CLASS, Mercedes SPRINTER.

How do I test the injectors on a OM612 engine?

Perform a leak-off test by connecting clear hoses to each injector return line and comparing fuel volumes at idle. You can also check injector correction values with a diagnostic scan tool or measure electrical resistance with a multimeter.

Injector Compatibility Checker

Explore Related Content

Diagnostic Guides

Need a Replacement OM612 Injector?

We stock 11 tested replacement injectors for the OM612 engine. All remanufactured, bench-tested, and supplied with a 12-month warranty.

View All Injectors Replacement Cost Guide Call 020 3355 6581