M9T678 Injector Problems – Symptoms, Causes & Fixes

Engine: M9T678 2 compatible injectors From £150

Common Injector Failures on the M9T678

The M9T678 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 2 tested replacement injectors for this engine from Bosch, Siemens VDO / Continental.

Vehicles fitted with the M9T678 include models from Nissan, Renault, Vauxhall. 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 M9T678 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

M9T678 Injector Replacement Cost

Parts (per injector)

£150–£200

Labour

£150–£400

Total (per injector)

£300–£600

Full replacement cost guide

Compatible Injectors for the M9T6782 found

0445110375Bosch

£150.00

562001910Siemens VDO / Continental

£200.00

Related Cross Reference Numbers for M9T678

0445110634 0986435205 0986435234 340023 A2C3335190080 AAA9858750010

Related Engine Codes

M9R630 M9R692 M9T670 M9T672 M9T676 M9T680

Frequently Asked Questions

What are common injector problems on the M9T678 engine?

The M9T678 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 M9T678 engine?

A remanufactured injector for the M9T678 engine typically costs £150–£200 per injector. Labour adds £150–£400 depending on accessibility. We found 2 compatible injectors for this engine.

Which vehicles use the M9T678 engine?

The M9T678 engine is found in vehicles from Nissan, Renault, Vauxhall. Common models include Nissan Interstar, Nissan NV400, Nissan Primastar, Renault Master, Renault Master III.

How do I test the injectors on a M9T678 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

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Need a Replacement M9T678 Injector?

We stock 2 tested replacement injectors for the M9T678 engine. All remanufactured, bench-tested, and supplied with a 12-month warranty.

View All Injectors Replacement Cost Guide Call 020 3355 6581

Diesel Injector Knowledge Centre

Remanufactured, Reconditioned or Refurbished Diesel Injectors — What We Supply

Whether you searched for remanufactured, reconditioned or refurbished diesel injectors, the product here is the same: a professionally remanufactured injector, not a cleaned-up used part. Each unit is dismantled, inspected against the manufacturer's test plan, worn components such as nozzles and control valves are replaced where the bench results call for it, then it is calibrated, tested and supplied ready to fit with its coding data. We remanufacture in-house in the UK and deliver nationwide.

Is a reconditioned injector the same as a remanufactured one?

In UK trade language the terms are used interchangeably. What matters is the process: our injectors are fully remanufactured — dismantled, worn parts replaced where required, recalibrated on the test bench and covered by a 12-month warranty — rather than simply cleaned and resold.