MajorCommonEngine

Holden Colorado: RG 2.8 LWH exhaust brake VNT actuator failure

RG 2.8 LWH exhaust brake VNT actuator failure is a common engine fault on the Holden Colorado on the 2012 onward cars, and we rate it major. Putting it right costs $600 to $2,200 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 11 documented faults on the Holden Colorado.

Vehicle: Holden Colorado
Engine: 2.8L
Years: 2012 onward
Fuel: diesel
System: Engine

This page covers the Holden Colorado as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Holden Colorado faults11 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph of the Turbocharger yet. We would rather show none than show a picture of a different part.

What goes wrong

The 2.8L Duramax LWH diesel in the RG Colorado uses a variable nozzle turbine (VNT) turbocharger whose movable vanes also function as an exhaust brake by restricting exhaust flow on overrun. The electric or vacuum actuator that moves the vane ring sticks due to carbon deposit accumulation on the vane pivot pins inside the turbine housing. Once stuck, exhaust braking is lost entirely. In some cases the vanes seize open, causing over-boost or limp mode. Actuator diaphragm failure in vacuum-type units is an additional failure mode. Repair may involve turbo removal and cleaning or actuator replacement.

What you would notice

No or greatly reduced engine braking on downhill driving with exhaust brake switch on
Check engine light with turbo-related DTC codes P0046, P0047, or P132B
Limp mode with reduced power
Black smoke on acceleration if vanes stick open
Exhaust brake dashboard light active but no braking felt

How to check it

Where to look. VNT actuator mounted on the turbocharger, located on the left side of the engine in the engine bay

Enable the exhaust brake function and drive down a moderate hill at 60 kph in 3rd gear with foot off the accelerator - there should be strong, noticeable retardation.
Scan the ECU for VNT or exhaust brake actuator fault codes.
Inspect the actuator rod movement while an assistant blips the exhaust brake switch; it should move freely through its full range.

Parts involved: Turbocharger.

What it costs to put right

$600 to $2,200 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

“Does the exhaust brake work correctly when descending hills?”
“Has a check engine light appeared related to turbo or exhaust brake faults?”
“Has the turbocharger been cleaned, rebuilt, or replaced?”

Now check the Holden Colorado you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.

Holden Colorado buyer questions

Is rg 2.8 lwh exhaust brake vnt actuator failure serious on a Holden Colorado?

We rate it major and common on the Holden Colorado. The 2.8L Duramax LWH diesel in the RG Colorado uses a variable nozzle turbine (VNT) turbocharger whose movable vanes also function as an exhaust brake by restricting exhaust flow on overrun. The electric or vacuum actuator that moves the vane ring sticks due to carbon deposit accumulation on the vane pivot pins inside the turbine housing. Once stuck, exhaust braking is lost entirely. In some cases the vanes seize open, causing over-boost or limp mode. Actuator diaphragm failure in vacuum-type units is an additional failure mode. Repair may involve turbo removal and cleaning or actuator replacement.

How much does it cost to fix on a Holden Colorado?

$600 to $2,200 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Holden Colorado years are affected?

Our research records this fault on the 2012 onward Holden Colorado. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.

How do I check for it before I buy?

Enable the exhaust brake function and drive down a moderate hill at 60 kph in 3rd gear with foot off the accelerator - there should be strong, noticeable retardation. Scan the ECU for VNT or exhaust brake actuator fault codes. Inspect the actuator rod movement while an assistant blips the exhaust brake switch; it should move freely through its full range. Look here: VNT actuator mounted on the turbocharger, located on the left side of the engine in the engine bay