Regeneration of Mercedes-Benz Citaro injectors – OM457, OM926, OM936
Professional regeneration of Mercedes-Benz Citaro, Conecto, Travego and Tourismo common rail injectors. OM457LA, OM926LA, OM936, OM470 engines. Bosch catalog numbers, diagnostics on the EPS 815 table, 12 months warranty. Silesia and shipping to PL.
Common Rail injectors in Mercedes-Benz buses – overview of systems and engines
Mercedes-Benz buses are one of the most common urban and intercity transport vehicles in Poland. Models such as Citaro (O530), Conecto, Tourismo and Travego are equipped with in-line and V-shaped engines with a common rail system, manufactured by Daimler Truck AG. The correct operation of these engines largely depends on the condition of the injectors - elements that generate and precisely dose fuel under pressure up to 1,800 bar.
At A-Core Diesel Serwis, we regenerate injectors for Mercedes-Benz buses from Euro 3 to Euro 6 engines. We have a Bosch EPS 815 test bench with software for all types of CR injectors used by Daimler, and each regeneration is confirmed with a test report.
Engine and injector types – Bosch catalog numbers
Below is a list of the most frequently serviced Mercedes-Benz engines used in buses and the corresponding catalog numbers of Bosch injectors:
| Bus model | Engine | Injector type | Bosch part number | Euro |
|---|---|---|---|---|
| Citaro O530 (up to 2006) | OM457LA | Bosch CRI2-16 | 0 445 120 078 / 0 445 120 079 | Euro 3 |
| Citaro O530 (2006–2011) | OM457LA E4 | Bosch CRI2-18 | 0 445 120 123 / 0 445 120 124 | Euro 4–5 |
| Citaro O530 G (articulated) | OM457LA / OM936 | Bosch CRI2-18 / CRI3 | 0 445 120 123 / 0 445 126 074 | Euro 4–6 |
| Conecto O345 | OM926LA | Bosch CRI2-P | 0 445 120 007 / 0 445 120 008 | Euro 3–4 |
| Tourismo RHD / SHD | OM457LA / OM470 | Bosch CRI2-18 / CRI3-20 | 0 445 120 123 / 0 445 126 002 | Euro 4–6 |
| Travego O580 | OM457LA / OM471 | Bosch CRI2-18 / CRI3-20 | 0 445 120 123 / 0 445 126 004 | Euro 4–6 |
| Citaro NGT (CNG) | OM936 G BlueTec 6 | Bosch CRI3-20 | 0 445 126 074 / 0 445 126 075 | Euro 6 |
Bosch CRI2 and CRI3 series injectors differ in the design of the control valve and the structure of the solenoid valve head. CRI3 used in Euro 6 engines operates at higher pressure and requires greater precision during regeneration.
The most common symptoms of injector failure in Citaro and Tourismo
Public transport buses work in extremely difficult conditions - short routes, frequent stops, idling for hours. This is one of the most destructive operating modes for the injection system.
Symptoms indicating problems with injectors
- Uneven engine operation at idle speed - hull vibrations, visible on the rev indicators
- White smoke during cold start – unburned diesel fuel due to a leaky nozzle
- Black smoke when accelerating – too high injection dose or incorrect angle
- Increase in fuel consumption – detectable by telematics systems of bus fleets
- Error codes in MR / INSITE – Mercedes diagnostics indicates a specific cylinder
- Engine clatter - characteristic metallic sound due to a leaky solenoid valve
- DTC P0200–P0207 – injector control circuit cylinder 1–7 (OM457 6-cyl.)
Mercedes STAR / XENTRY error codes for bus engines
| DTC | Description | Engine |
|---|---|---|
| P0201–P0206 | Cylinder injector circuit. 1–6 – open/short circuit | OM457 (6-cyl.) |
| P0261–P0266 | Low cylinder control signal. 1–6 | OM457 / OM926 |
| P0267–P0272 | High cylinder control signal. 1–6 | OM457 / OM926 |
| P0087 | Fuel pressure too low - CR rail | all |
| P0093 | Fuel system back-leak | all |
| P2146 / P2149 | Power supply bank 1/2 injectors - break | OM470 / OM471 |
Regeneration of Mercedes injectors – process and scope of work
Stage 1 – Diagnostics and pre-test on the Bosch EPS 815 table
Each injector received from a Mercedes bus is identified with a serial number and tested on a Bosch EPS 815 test bench in the condition in which it came to the service. We record injection doses for idle, half load and full load operating points, back-leak and solenoid valve response time. The pre-test results constitute the initial documentation of the order.
Stage 2 – Disassembly and inspection under clean conditions
The injectors are dismantled in a dedicated station with air filtration. We check the condition of the needle and seat (tolerance below 1 μm), control valve, solenoid valve, seals and mesh filters. Each worn element is measured with a micrometer and photographed for service documentation.
Stage 3 – Component replacement and calibration
We only use original Bosch repair kits (F 00V C99 002 / F 00V C99 003 / F 00V C99 004 for CRI2, F 00V C99 005 for CRI3) or OEM parts. After assembly, each injector is calibrated with the selection of spacers with an accuracy of to 1 μm.
Stage 4 – Post-test and report
The regenerated injector undergoes a full final test on EPS 815. Acceptance tolerance: ±2% from Bosch/Mercedes nominal values. The test report (pre and post) is printed and attached to the documentation returned with the injector.
Supported Mercedes-Benz bus models
- Citaro O530 – solo versions, articulated (O530G), Euro 3/4/5/6
- Citaro LE / Citaro K – low floor, OM926LA and OM936 engines
- Conecto O345 – OM926LA low-floor buses
- Tourismo RHD / SHD – OM457LA, OM470 tourist coaches
- Travego O580 – long-distance coaches OM457LA, OM471
- Intouro / Integro – regional coaches OM926, OM470
- Sprinter City / Transfer – OM651 and OM642 CR minibuses
Service for companies and carriers - bus fleets
A-Core Diesel The website serves municipal transport companies (MZK, ZTM, MPK), employee transport companies, tour operators and private carriers. For regular customers with bus fleets, we offer:
- Priority delivery time (express within 3 business days)
- Shipping service - disassembly on your side, shipping by courier to Knurów
- Pre/post test report for each injector with serial number
- Possibility of regeneration in batches (e.g. 30 pieces from fleet inspection)
- 12-month warranty for each regeneration
Frequently asked questions - FAQ
Are OM457 injectors from Euro 3 and Euro 5 identical?
No. OM457LA Euro 3 uses CRI2-16 injectors (0 445 120 078) and Euro 5 uses CRI2-18 (0 445 120 123). They differ in the structure of the solenoid valve and calibration codes. Before ordering, we always check the catalog number from the engine plate or VIN number of the bus.
How often should you regenerate injectors in Citaro?
In intensive urban use (150-250 thousand km/year), we recommend injectors inspection every 400,000-600,000 km or when the first symptoms appear. Regular replacement of fuel filters every 60,000 km significantly extends the life of the injectors.
Is programming in STAR/XENTRY necessary after regeneration?
CRI2 injectors do not have individual calibration codes - after mechanical regeneration, they do not require reprogramming the controller. CRI3 injectors (Euro 6, OM936/OM470/OM471) may require new correction values to be entered by XENTRY - we inform the customer about this when ordering.
Do you accept injectors from electric-diesel buses (hybrid)?
Yes - hybrid Citaros with the BlueTec Hybrid drive system use the same CRI injectors as conventional versions. Part of the diesel system is identical.
Contact us
A-Core Diesel Serwis, Knurów (Silesia)
Tel.: +48 504 511 170 – Mon–Fri 8:00–16:00
Free quote after initial diagnostics. Shipping service – all over Poland.
Having a problem with your injection pump?
Contact us – we respond during working hours (Mon–Fri 8:00–16:00).